Author Topic: Where does moisture barrier go in floor and do I need one?  (Read 13892 times)

CmFtns

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Where does moisture barrier go in floor and do I need one?
« on: January 24, 2016, 07:31:16 PM »
I am doing a kitchen remodel and I ripped out:
The old tile flooring...
and then a layer of plywood...
and then a layer of tongue and groove pine flooring...

and finally got down to a diagonal wooden sub floor slats that are installed over the floor joists which span a dirt crawl space.

Here's a Picture to give you an idea


Now after some research i'm confused as ever on how to prep this for a new floating floor installation.

The kitchen is connected to a dining room that has a concrete slab floor which is currently 3/4" higher than the kitchen and I want them to be the same height. I was planning on installing 3/4" plywood over this sub floor so I have a nice even flat surface that is the same height as the dining room concrete slab. I would then installing a floating floor throughout both rooms.

My questions are
1) Do I need a moisture barrier somewhere in-between all these layers of flooring? if so where does it go? above subfloor and below plywood? above plywood and below floating floor?

2) Should I use plywood for this and if so what type of plywood do I use for this or is there another method to get this floor ready?
« Last Edit: January 24, 2016, 07:37:58 PM by comfyfutons »

lthenderson

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #1 on: January 25, 2016, 07:34:39 AM »
My questions are
1) Do I need a moisture barrier somewhere in-between all these layers of flooring? if so where does it go? above subfloor and below plywood? above plywood and below floating floor?

2) Should I use plywood for this and if so what type of plywood do I use for this or is there another method to get this floor ready?

1) The moisture barrier should ideally be on top of the dirt in the crawl space and sealed to the perimeter of the house and anchored with a layer of gravel. The gravel helps to hold it in place and protect it from puncturing when you are crawling around in the crawl space.

2. Since you already have supporting structure above the floor joists, you essentially are just putting down underlayment to get the height up to match your neighboring room. You can you just about whatever you want but the most cost effective will probably be 3/4" particle board or wafer board. You can certainly use plywood but it will be overkill with regards to the support and will cost quite a bit more.

CmFtns

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #2 on: January 25, 2016, 08:29:38 AM »
My questions are
1) Do I need a moisture barrier somewhere in-between all these layers of flooring? if so where does it go? above subfloor and below plywood? above plywood and below floating floor?

2) Should I use plywood for this and if so what type of plywood do I use for this or is there another method to get this floor ready?

1) The moisture barrier should ideally be on top of the dirt in the crawl space and sealed to the perimeter of the house and anchored with a layer of gravel. The gravel helps to hold it in place and protect it from puncturing when you are crawling around in the crawl space.

2. Since you already have supporting structure above the floor joists, you essentially are just putting down underlayment to get the height up to match your neighboring room. You can you just about whatever you want but the most cost effective will probably be 3/4" particle board or wafer board. You can certainly use plywood but it will be overkill with regards to the support and will cost quite a bit more.

1) Okay so I have looked into encapsulating the crawl space and I think it is unreasonably difficult to accomplish. There is less than 2 feet of space to work down there and there's pipes and obstacles that hang down even lower and it's scary and dirty. Its really not something I want to do so is there a second best option.

2) The layer of tongue and groove flooring that I ripped out and the plywood that was on top of that was very rotten in places so I am hesitant to use a cheap particleboard straight on top of the subfloor because I think it will just rot away. However the subfloor that is in the picture is in much better shape making me think it is pressure treated planks. That's why I was thinking either put down some kind of moisture barrier or use a more expensive pressure treated plywood to try to prevent rot right below my new flooring.

lthenderson

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #3 on: January 25, 2016, 11:10:49 AM »
Anything below the moisture barrier will be subjected to moisture and thus rot. If you add the moisture barrier above any wood, it will eventually rot. The reason your subfloor that you tore up was rotten in places may have been due to the lack of the moisture barrier. The wood may be pressure treated but even pressure treated wood rots in contact with moisture for long periods of time. I've replaced enough rotten sill plates and poles in pole barns to know that even if you use treated wood and subject it to moisture, you will eventually be replacing it.

It isn't pleasant sometimes dealing with crawl spaces but I think it is less pleasant doing something incorrectly and redoing it again and at considerable more expense.

Jmoody10

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #4 on: January 25, 2016, 11:21:19 AM »
What kind of insulation does your crawl space have? If you can put closed cell foam under the subfloor, that would serve as a moisture barrier between crawl space and home.

CmFtns

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #5 on: January 25, 2016, 12:44:25 PM »
Anything below the moisture barrier will be subjected to moisture and thus rot. If you add the moisture barrier above any wood, it will eventually rot. The reason your subfloor that you tore up was rotten in places may have been due to the lack of the moisture barrier. The wood may be pressure treated but even pressure treated wood rots in contact with moisture for long periods of time. I've replaced enough rotten sill plates and poles in pole barns to know that even if you use treated wood and subject it to moisture, you will eventually be replacing it.

It isn't pleasant sometimes dealing with crawl spaces but I think it is less pleasant doing something incorrectly and redoing it again and at considerable more expense.

Thanks for your comments and I get where your coming from, I really do, but just wanted to throw out some more thoughts before I decide that I may want to tackle this.

Almost no houses down here have encapsulated crawlspaces and the sub floor you see has been exposed to the crawlspace 'elements' for 58 years which includes awful exterior grading that causes water pool against the foundation wall and to pour under the house every time it rains (I am going to deal with drainage issue soon so this will significantly improve)

With that being said, the floor still seems structurally sound when I jump around on it even after all that time. So I'm wondering if i'm going to get a real return on investment with a crawl space encapsulation. When it comes time to sell I believe no one will care about the encapsulated crawl space. I honestly just need the installation to last till I no longer own the home which will more than likely be less than 15 years.

I really wanted to encapsulate the crawl space but after considering it and looking into what went into it, I had pretty much decided that if the house has stood for this long... it will probably last another 20 years.

What benefit will I see over the next 20 years if I encapsulate the crawl space and if I was not going to encapsulate it is there a second best option to protect at least some of the flooring layers in the kitchen?

What kind of insulation does your crawl space have? If you can put closed cell foam under the subfloor, that would serve as a moisture barrier between crawl space and home.

There is nothing down there just floor joists ==> subfloor ==> floors
« Last Edit: January 25, 2016, 12:47:58 PM by comfyfutons »

Papa bear

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Where does moisture barrier go in floor and do I need one?
« Reply #6 on: January 25, 2016, 12:54:42 PM »
Anything below the moisture barrier will be subjected to moisture and thus rot. If you add the moisture barrier above any wood, it will eventually rot. The reason your subfloor that you tore up was rotten in places may have been due to the lack of the moisture barrier. The wood may be pressure treated but even pressure treated wood rots in contact with moisture for long periods of time. I've replaced enough rotten sill plates and poles in pole barns to know that even if you use treated wood and subject it to moisture, you will eventually be replacing it.

It isn't pleasant sometimes dealing with crawl spaces but I think it is less pleasant doing something incorrectly and redoing it again and at considerable more expense.

Thanks for your comments and I get where your coming from, I really do, but just wanted to throw out some more thoughts before I decide that I may want to tackle this.

Almost no houses down here have encapsulated crawlspaces and the sub floor you see has been exposed to the crawlspace 'elements' for 58 years which includes awful exterior grading that causes water pool against the foundation wall and to pour under the house every time it rains (I am going to deal with drainage issue soon so this will significantly improve)

With that being said, the floor still seems structurally sound when I jump around on it even after all that time. So I'm wondering if i'm going to get a real return on investment with a crawl space encapsulation. When it comes time to sell I believe no one will care about the encapsulated crawl space. I honestly just need the installation to last till I no longer own the home which will more than likely be less than 15 years.

I really wanted to encapsulate the crawl space but after considering it and looking into what went into it, I had pretty much decided that if the house has stood for this long... it will probably last another 20 years.

What benefit will I see over the next 20 years if I encapsulate the crawl space and if I was not going to encapsulate it is there a second best option to protect at least some of the flooring layers in the kitchen?

What kind of insulation does your crawl space have? If you can put closed cell foam under the subfloor, that would serve as a moisture barrier between crawl space and home.

There is nothing down there just floor joists ==> subfloor ==> floors

Be it job great or small, do it right or not at all.  I'd be curious where else you'll cut corners in this remodel if I was a buyer.  Are you permitting this?

ETA: you have good answers here above.  You know what you have to do to make it right, correct, and safe.  Vapor barrier over the floor in the crawl, or closed cell foam underneath.

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« Last Edit: January 25, 2016, 12:59:15 PM by Papa bear »

nereo

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #7 on: January 25, 2016, 01:35:12 PM »

Be it job great or small, do it right or not at all.  I'd be curious where else you'll cut corners in this remodel if I was a buyer.  Are you permitting this?

ETA: you have good answers here above.  You know what you have to do to make it right, correct, and safe.  Vapor barrier over the floor in the crawl, or closed cell foam underneath.
+1.  The job you speak of is annoying, uncomfortable and dirty, but it will be just a few hours of your life and very little additional cost to do it correctly.  It may save you personally by preventing moisture from causing your new flooring to warp or cup, and should certainly help the future owners.  In the long term, taking short cuts hurts all of us.

CmFtns

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #8 on: January 25, 2016, 01:49:00 PM »
Anything below the moisture barrier will be subjected to moisture and thus rot. If you add the moisture barrier above any wood, it will eventually rot. The reason your subfloor that you tore up was rotten in places may have been due to the lack of the moisture barrier. The wood may be pressure treated but even pressure treated wood rots in contact with moisture for long periods of time. I've replaced enough rotten sill plates and poles in pole barns to know that even if you use treated wood and subject it to moisture, you will eventually be replacing it.

It isn't pleasant sometimes dealing with crawl spaces but I think it is less pleasant doing something incorrectly and redoing it again and at considerable more expense.

Thanks for your comments and I get where your coming from, I really do, but just wanted to throw out some more thoughts before I decide that I may want to tackle this.

Almost no houses down here have encapsulated crawlspaces and the sub floor you see has been exposed to the crawlspace 'elements' for 58 years which includes awful exterior grading that causes water pool against the foundation wall and to pour under the house every time it rains (I am going to deal with drainage issue soon so this will significantly improve)

With that being said, the floor still seems structurally sound when I jump around on it even after all that time. So I'm wondering if i'm going to get a real return on investment with a crawl space encapsulation. When it comes time to sell I believe no one will care about the encapsulated crawl space. I honestly just need the installation to last till I no longer own the home which will more than likely be less than 15 years.

I really wanted to encapsulate the crawl space but after considering it and looking into what went into it, I had pretty much decided that if the house has stood for this long... it will probably last another 20 years.

What benefit will I see over the next 20 years if I encapsulate the crawl space and if I was not going to encapsulate it is there a second best option to protect at least some of the flooring layers in the kitchen?

What kind of insulation does your crawl space have? If you can put closed cell foam under the subfloor, that would serve as a moisture barrier between crawl space and home.

There is nothing down there just floor joists ==> subfloor ==> floors

Be it job great or small, do it right or not at all.  I'd be curious where else you'll cut corners in this remodel if I was a buyer.  Are you permitting this?

ETA: you have good answers here above.  You know what you have to do to make it right, correct, and safe.  Vapor barrier over the floor in the crawl, or closed cell foam underneath.

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You guys are kinda harsh... let's just calm down for a second... I am not trying to cut corners and I fully intend to do everything the 'right' way to the fullest of my abilities. I will live in this house for many years and am treating it like my own... I'm not just trying to flip it or trick buyers.

I have read about permits and I do not believe anything I am doing or will do requires a permit be pulled (correct me if i'm wrong)
-I am not moving any walls
-I am not adding or moving any electrical sockets
-I am not adding or moving any plumbing (rather just hooking up a new sink in the same spot)

I didn't know this whole forum was full of stringent city building inspectors... A lot of times we who call ourselves mustacians might do things a little differently than the norm and since I am not an expert contractor I thought we could have some discussions about why these methods are necessary and possible other solutions.

I guess what i'm saying is that I can not rebuild my entire house every time there is a breakthrough in the 'right' way to do things and the standard for crawl space encapsulation obviously wasn't always a thing when 99% of the houses down here were built. If it was as important as you all are making it out to be then there wouldn't be so many old houses still standing.

I think some of you are thinking i'm just scared of the tiniest bit of dirt... This is not the case. I am telling you that there is no room to sit up there is no room to work my face would be 2 inches from the dirt with my head bumping up against the floor joists. This is a HUGE undertaking because of space constraints under the house.

I also thought that there might be regional differences in standards and that might be a reason there aren't very many encapsulated crawl spaces in Florida. I've read that the natural air is so humid that even an encapsulated place will have super high humidity and with no airflow because of the encapsulation it can be worse than a vented space.
« Last Edit: January 25, 2016, 02:02:21 PM by comfyfutons »

Papa bear

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #9 on: January 25, 2016, 02:42:16 PM »
Every time you open up a wall, you're supposed to bring the project up to code. It's open and available, so you should fix it.  I don't know your local jurisdiction, but from the work in the picture, my municipality would require a permit.

I was harsh because it sounds like you are making excuses for not doing the work.  You made some arguments that you jumped on the floor to test for strength (not really the best test), you only need it to last until you move out,  "that's the way they used to do it" and "no one else has it that way" sounds like you could care less about this project and you're looking for someone to justify your own thoughts so you can slap on your new floor. That mindset causes countless other problems down the road to unsuspecting buyers. 

As someone who has remodeled multiple properties, it's atrocious what I find hiding under the floor and behind walls.  Sure it "worked" but that doesn't mean it was safe, always going to work, or not cause damages well beyond what it would have cost to do it right in the first place. 




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nereo

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #10 on: January 25, 2016, 02:56:57 PM »
speaking for myself only, my comment was meant to be encouraging and aimed at getting you over that hump of "but this is really going to suck".  I've encountered my fair share of projects where there was one step that I really wanted to skip.  In the spirit of MMM ("badassity" and all that) I'm saying that you can do this, and that it really will be a small amount of time and cost.

Also, I think there's a very real possiblity that **you** will directly benefit.  Before you had tile flooring; if you put in wood or composite or engineered floor it easily warp or cup with too much moisture. 

zolotiyeruki

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #11 on: January 25, 2016, 03:10:02 PM »
In my understanding, rotting wood and mold come from too much moisture.  That can be either a leak in the building envelope, flooding from inside or outside, or condensation, or moisture wicking up from the ground.  Since there's a crawlspace, the flooding and wicking aren't an issue (barring hurricanes), and as long as you keep the exterior walls maintained, those leaks aren't an issue either, which leaves you with condensation.

With condensation, you want the vapor barrier close to the warm, humid side.  Since you're in FL, that would mean the vapor barrier goes close to the ground, or at least attached to the under side of the joists.  If you put it on top of your subfloor, then the humidity will end up condensing on the vapor barrier which is right next to your air-conditioned space.  Right on your subfloor.

If it were me, I'd stuff batt insulation between the joists from underneath, then run a vapor barrier across the bottom of the joists.  Alternatively, spray foam the under side of the whole floor.

AlanStache

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #12 on: January 25, 2016, 03:14:56 PM »
A lack of moisture barrier was flagged by the home inspector when I bought recently, I chose to push on other things but I could have asked for this before closing.  Yes it is a negotiation but materials for the barrier are very cheap.

robartsd

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #13 on: January 25, 2016, 03:17:21 PM »
I agree that crawlspace encapsulation would be a difficult retrofit and you've given good reasons it might not be appropriate in your region. Crawl spaces generally only require 18" below joists and 12" below griders; so your "less than 2 feet" sounds pretty typical to me. I'd at least consider doing a closed cell insulation spray under your floor from the crawlspace as that would provide some energy savings as well as protect the floor from mositure below (I also envision it as being easier than laying a vapor barrier and gravel over the dirt - especially if you would have to escavate to maintain the required crawlspace depth when complete).

CmFtns

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #14 on: January 25, 2016, 03:38:46 PM »
The the average humidity in the middle of the driest months are 49% low with 89% highs
The average humidity in the summer is 62% low to 94% highs

If I put plastic in the crawl space the humidity down there will still be very high... everything I read on the internet about encapsulating crawl spaces talks about its use for cold climates. I am not against doing this... I just want to make sure the benefit will justify all the work/cost. I just have not found anything about using it in hot humid climates so I want to make sure i'm not creating an environment that is worse for mold and rot and that I am getting advice that applies to my climate zone.




speaking for myself only, my comment was meant to be encouraging and aimed at getting you over that hump of "but this is really going to suck".  I've encountered my fair share of projects where there was one step that I really wanted to skip.  In the spirit of MMM ("badassity" and all that) I'm saying that you can do this, and that it really will be a small amount of time and cost.

Also, I think there's a very real possiblity that **you** will directly benefit.  Before you had tile flooring; if you put in wood or composite or engineered floor it easily warp or cup with too much moisture. 

There is 1000sqft of hardwood throughout the other rooms in the house and there is no problems with cupping or warping... Also I am probably putting down some kind of click-lock vynil/synthetic stone/slate flooring in kitchen/dining area.
« Last Edit: January 25, 2016, 03:45:29 PM by comfyfutons »

Midwest

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #15 on: January 25, 2016, 04:00:10 PM »
Anything below the moisture barrier will be subjected to moisture and thus rot. If you add the moisture barrier above any wood, it will eventually rot. The reason your subfloor that you tore up was rotten in places may have been due to the lack of the moisture barrier. The wood may be pressure treated but even pressure treated wood rots in contact with moisture for long periods of time. I've replaced enough rotten sill plates and poles in pole barns to know that even if you use treated wood and subject it to moisture, you will eventually be replacing it.

It isn't pleasant sometimes dealing with crawl spaces but I think it is less pleasant doing something incorrectly and redoing it again and at considerable more expense.

Thanks for your comments and I get where your coming from, I really do, but just wanted to throw out some more thoughts before I decide that I may want to tackle this.

Almost no houses down here have encapsulated crawlspaces and the sub floor you see has been exposed to the crawlspace 'elements' for 58 years which includes awful exterior grading that causes water pool against the foundation wall and to pour under the house every time it rains (I am going to deal with drainage issue soon so this will significantly improve)

With that being said, the floor still seems structurally sound when I jump around on it even after all that time. So I'm wondering if i'm going to get a real return on investment with a crawl space encapsulation. When it comes time to sell I believe no one will care about the encapsulated crawl space. I honestly just need the installation to last till I no longer own the home which will more than likely be less than 15 years.

I really wanted to encapsulate the crawl space but after considering it and looking into what went into it, I had pretty much decided that if the house has stood for this long... it will probably last another 20 years.

What benefit will I see over the next 20 years if I encapsulate the crawl space and if I was not going to encapsulate it is there a second best option to protect at least some of the flooring layers in the kitchen?

What kind of insulation does your crawl space have? If you can put closed cell foam under the subfloor, that would serve as a moisture barrier between crawl space and home.

There is nothing down there just floor joists ==> subfloor ==> floors

Did you read the instructions for the floating floor?  .  We had a dirt crawl space in the midwest.  Plywood and/or osb don't fair well in that environment. 

In your situation I might consider putting tar paper down over the floor you are looking at followed by plywood or osb.  Not sure if that's the correct answer, but that's where I'd be looking if it's not feasible to take care of the problem in the crawl space.

Regarding permits, where in the world are people pulling permits for fixing a subfloor and putting a finish floor down?
« Last Edit: January 25, 2016, 04:02:57 PM by Midwest »

CmFtns

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #16 on: January 25, 2016, 04:48:25 PM »
Did you read the instructions for the floating floor?  .  We had a dirt crawl space in the midwest.  Plywood and/or osb don't fair well in that environment. 

In your situation I might consider putting tar paper down over the floor you are looking at followed by plywood or osb.  Not sure if that's the correct answer, but that's where I'd be looking if it's not feasible to take care of the problem in the crawl space.

Regarding permits, where in the world are people pulling permits for fixing a subfloor and putting a finish floor down?

Yea that's kinda what I was thinking initially except I thought thick pressure treated plywood would fare much better then the old stuff I ripped up...but I do want to do more research on how to deal with my crawlspace in this situation.

At first I figured if it's stood for 60 years while rain was allowed to flood under the house then it should last another 60 years if I deal with drainage issues and keep it mostly dry down there... I had an inspection on the house and he looked around down there as best he could and didn't see any mold or termites or serious rotting issues.

I haven't yet picked out the floor. I guess I should go look up what the brands I'm looking at recommend or ask the guys at the store to show me the boxes so i can grab a few pictures of the directions.

I totally agree with the permits... In my view the only thing I should have to pull a permit for is if i'm adding on sqft to the house or taking out a load bearing wall or something serious like that.

Midwest

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #17 on: January 25, 2016, 04:58:40 PM »
What is the condition of the subfloor in your pics?  With our dirt subfloor, joists were fine, but 40 year old plywood was junk in places (our dryer was vented directly into the crawl space for quite a while until I fixed).  I suspect that subfloor will dry pretty well and hold up better than plywood or osb.

You might check how much of a moisture barrier the plywood will be in and of itself.

FYI, those floating floors require the floor to be ridiculously level.  Buy a six or eight foot level and use it.  If I had it to do again, I think putting down a real hardwood floor would have been simpler than leveling to the extent required.  That assumes of course that the moisture wouldn't destroy a real hardwood floor.

Also, you might look at building science.  They have a ton of information. 
« Last Edit: January 25, 2016, 05:02:08 PM by Midwest »

CmFtns

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #18 on: January 25, 2016, 05:07:38 PM »
What is the condition of the subfloor in your pics?  With our dirt subfloor, joists were fine, but 40 year old plywood was junk in places (our dryer was vented directly into the crawl space for quite a while until I fixed).  I suspect that subfloor will dry pretty well and hold up better than plywood or osb.

You might check how much of a moisture barrier the plywood will be in and of itself.

FYI, those floating floors require the floor to be ridiculously level.  Buy a six or eight foot level and use it.  If I had it to do again, I think putting down a real hardwood floor would have been simpler than leveling to the extent required.  That assumes of course that the moisture wouldn't destroy a real hardwood floor.

What you see in the picture is basically long planks that go diagonally span across floor joists which are held around 1-1.5 feet above dirt by the foundation wall and cinderblock footers. The wood is really dirty and it's obvious that there's been some water damage and a little bit of rot but they are dry now and seem to be in decent condition. They don't have any 'give' when you walk over them or anything.

I plan to use vynil tiles that click-lock together that are 12" x 24" so maybe it doesn't have to be exactly flat but it's already pretty flat.
« Last Edit: January 25, 2016, 05:10:34 PM by comfyfutons »

lakemom

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #19 on: January 25, 2016, 05:28:42 PM »
The house we purchased a little over 1 year ago as a rental has a dirt crawl.  In the crawl attached to the floor joists via staples is Tyvek (or store brand).  It was like this when we purchased it and was built that way when new (early '80's modular).  So we have dirt floor, 3' of space, Tyvek (stapled down and taped at seams) above the Tyvek is fiberglass insulation between the joists, all the wiring and all the plumbing.  This is in northern Indiana.  The crawl is vented with the little vents in the foundation that you open in summer and close in winter.

Fishindude

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #20 on: January 26, 2016, 05:30:23 AM »
I have an old house like yours and understand the frustration.
Although it may not be built 100% correctly, it is doing the job and has provided a place for people to live for a real long time.   It is impractical to fix all of these issues.  You start digging into stuff and it's like ...... Where do I quit?  It's all screwed up, clear down to the rock foundation.

In your case, I'd just screw down a sub-floor over that plank decking and install your new finished floor.   I'd use either OSB sheathing or a cement board material, whatever the manufacturer of your new flooring recommends.

Midwest

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #21 on: January 26, 2016, 07:45:04 AM »
What is the condition of the subfloor in your pics?  With our dirt subfloor, joists were fine, but 40 year old plywood was junk in places (our dryer was vented directly into the crawl space for quite a while until I fixed).  I suspect that subfloor will dry pretty well and hold up better than plywood or osb.

You might check how much of a moisture barrier the plywood will be in and of itself.

FYI, those floating floors require the floor to be ridiculously level.  Buy a six or eight foot level and use it.  If I had it to do again, I think putting down a real hardwood floor would have been simpler than leveling to the extent required.  That assumes of course that the moisture wouldn't destroy a real hardwood floor.

What you see in the picture is basically long planks that go diagonally span across floor joists which are held around 1-1.5 feet above dirt by the foundation wall and cinderblock footers. The wood is really dirty and it's obvious that there's been some water damage and a little bit of rot but they are dry now and seem to be in decent condition. They don't have any 'give' when you walk over them or anything.

I plan to use vynil tiles that click-lock together that are 12" x 24" so maybe it doesn't have to be exactly flat but it's already pretty flat.

I thought my floor was pretty flat too (my house was built in 1990).  The first room I layed has some bounce because it wasn't as level as I thought.

In the 2nd room, I shimmed with vinyl tile as needed (you could also use leveling compound) and put 1/4" underlayment down.  No movement much better install.

FYI, you could always decide to install a moisture barrier in the crawl space at a later date.  When I'm in the midst of a project and problems keep coming up it becomes difficult to look objectively at additional problems.

Also, you might want to ask manufacturer before putting cabinets on a floating floor.  My cabinets are floating slightly above the floor so it can float as per manufacturers recommendation.

CmFtns

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #22 on: January 26, 2016, 08:25:00 AM »
What is the condition of the subfloor in your pics?  With our dirt subfloor, joists were fine, but 40 year old plywood was junk in places (our dryer was vented directly into the crawl space for quite a while until I fixed).  I suspect that subfloor will dry pretty well and hold up better than plywood or osb.

You might check how much of a moisture barrier the plywood will be in and of itself.

FYI, those floating floors require the floor to be ridiculously level.  Buy a six or eight foot level and use it.  If I had it to do again, I think putting down a real hardwood floor would have been simpler than leveling to the extent required.  That assumes of course that the moisture wouldn't destroy a real hardwood floor.

What you see in the picture is basically long planks that go diagonally span across floor joists which are held around 1-1.5 feet above dirt by the foundation wall and cinderblock footers. The wood is really dirty and it's obvious that there's been some water damage and a little bit of rot but they are dry now and seem to be in decent condition. They don't have any 'give' when you walk over them or anything.

I plan to use vynil tiles that click-lock together that are 12" x 24" so maybe it doesn't have to be exactly flat but it's already pretty flat.

I thought my floor was pretty flat too (my house was built in 1990).  The first room I layed has some bounce because it wasn't as level as I thought.

In the 2nd room, I shimmed with vinyl tile as needed (you could also use leveling compound) and put 1/4" underlayment down.  No movement much better install.

FYI, you could always decide to install a moisture barrier in the crawl space at a later date.  When I'm in the midst of a project and problems keep coming up it becomes difficult to look objectively at additional problems.

Also, you might want to ask manufacturer before putting cabinets on a floating floor.  My cabinets are floating slightly above the floor so it can float as per manufacturers recommendation.

I was thinking about putting leveling compound over whatever plywood or other underlayment I end up putting down if it is not level enough... and your right I can put crawl space encapsulation in at any time in the future which I have been debating on doing for a few months now but think other stuff is more pressing because i'm trying to move in eventually.

I am not puting cabinets on top of the floor... I am putting the cabinets in first then putting the floor just under the cabinet's kick plates.

Why does the floor have to be perfectly flat? does the floor pieces wobble and rock around on it when you walk on it otherwise?

Midwest

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #23 on: January 26, 2016, 10:16:01 AM »
What is the condition of the subfloor in your pics?  With our dirt subfloor, joists were fine, but 40 year old plywood was junk in places (our dryer was vented directly into the crawl space for quite a while until I fixed).  I suspect that subfloor will dry pretty well and hold up better than plywood or osb.

You might check how much of a moisture barrier the plywood will be in and of itself.

FYI, those floating floors require the floor to be ridiculously level.  Buy a six or eight foot level and use it.  If I had it to do again, I think putting down a real hardwood floor would have been simpler than leveling to the extent required.  That assumes of course that the moisture wouldn't destroy a real hardwood floor.

What you see in the picture is basically long planks that go diagonally span across floor joists which are held around 1-1.5 feet above dirt by the foundation wall and cinderblock footers. The wood is really dirty and it's obvious that there's been some water damage and a little bit of rot but they are dry now and seem to be in decent condition. They don't have any 'give' when you walk over them or anything.

I plan to use vynil tiles that click-lock together that are 12" x 24" so maybe it doesn't have to be exactly flat but it's already pretty flat.

I thought my floor was pretty flat too (my house was built in 1990).  The first room I layed has some bounce because it wasn't as level as I thought.

In the 2nd room, I shimmed with vinyl tile as needed (you could also use leveling compound) and put 1/4" underlayment down.  No movement much better install.

FYI, you could always decide to install a moisture barrier in the crawl space at a later date.  When I'm in the midst of a project and problems keep coming up it becomes difficult to look objectively at additional problems.

Also, you might want to ask manufacturer before putting cabinets on a floating floor.  My cabinets are floating slightly above the floor so it can float as per manufacturers recommendation.

I was thinking about putting leveling compound over whatever plywood or other underlayment I end up putting down if it is not level enough... and your right I can put crawl space encapsulation in at any time in the future which I have been debating on doing for a few months now but think other stuff is more pressing because i'm trying to move in eventually.

I am not puting cabinets on top of the floor... I am putting the cabinets in first then putting the floor just under the cabinet's kick plates.

Why does the floor have to be perfectly flat? does the floor pieces wobble and rock around on it when you walk on it otherwise?

On the cabinets, good deal.  We actually built up the floor where the cabinet was going so it would sit slightly above the finish floor, installed the finish floor and then put the base cabinets in. 

With regard to flatness, look at instructions for your particular floor and follow them. 

The floating hardwood floor I put down required no more than 1/8 or 1/16 variation over 6 or 8 feet.  On the first floor I put down, there is movement and some noise because it wasn't flat enough.  If I didn't have cabinets involved, I would pull it and level it out because its annoying and will shorten the life of the floor.

On the 2nd room I did (same product), I leveled it to at least their specs.  Much happier with that install.

Don't make the same mistake I did on the flatness.

Good luck with the house.
« Last Edit: January 26, 2016, 10:21:19 AM by Midwest »

paddedhat

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #24 on: January 28, 2016, 06:23:05 AM »
First, I'm a builder with thirty years experience and I have built new homes in many climates. Next, you're correct, a lot of posters here respond with what they know to be correct in their specific region, and it has nothing to do with yours. Finally, the whole " everybody is a building inspector" situation gets a bit old. There are plenty of jurisdictions that have rules like the ones covering your case, or like most in my area, have no interest in what you do to remodel, or repair existing structure.

Now, on to the situation you face. As you correctly note, there are hundreds of thousands of uninsulated, vented crawl spaces in your state, and they obviously function, as many are supporting homes that are a hundred years old. Obviously, they are not optimal, since the vast majority of new construction takes place on concrete slabs, avoiding crawls. Your board sheathing is solid enough to build up, but not treated lumber. It may be one of the older southern pines that can be pretty rot resistant. In your situation, I would first re-nail, or screw all the boards to the joists. This may be a bit of a challenge, as old wood can be amazingly hard. You may find success with 2-1/2" deck screws, or #10 common nails. It may be so hard that only a nail gun will do the job. Next, you need to find a floor sheathing product by Huber lumber, it's called Advantech. It looks like OSB (chip board) but it is about the most water resistant stuff out there. It's heavy, hard on saw blades, and about as expensive as regular plywood. It comes with a fifty year structural guarantee, and it does not swell or delaminate. You probably won't have much luck landing the edges on floor joists, since many older buildings were not framed on exact 16" centers. I would install it with an air nailer, using 8D ring shank nails designed for installing subfloors. If you want to do a really solid job, you could use a belt sander, or floor sander, with a very aggressive belt, and grind the original boards clean. You could then both nail and use subfloor adhesive to bond the Advantech to the old board subfloor.  Advantech is a single ply subfloor, you can patch the joints and nail holes, and use the tiles you mentioned. Additional vapor barriers, used with an OSB or Advantech subflooring, might lead to rot, as the material is impermeable, and in effect it's own vapor barrier. You never want multiple vapor barriers in a situation like this.
« Last Edit: January 28, 2016, 06:30:56 AM by paddedhat »

Papa bear

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #25 on: January 28, 2016, 06:46:14 AM »
http://www.floridabuilding.org/fbc/commission/fbc_0512/commission_education_poc/332/332-1-material.pdf


Read section on crawl spaces and remedy in a way you see acceptable. 


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CmFtns

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #26 on: January 28, 2016, 12:29:20 PM »
First, I'm a builder with thirty years experience and I have built new homes in many climates. Next, you're correct, a lot of posters here respond with what they know to be correct in their specific region, and it has nothing to do with yours. Finally, the whole " everybody is a building inspector" situation gets a bit old. There are plenty of jurisdictions that have rules like the ones covering your case, or like most in my area, have no interest in what you do to remodel, or repair existing structure.

Now, on to the situation you face. As you correctly note, there are hundreds of thousands of uninsulated, vented crawl spaces in your state, and they obviously function, as many are supporting homes that are a hundred years old. Obviously, they are not optimal, since the vast majority of new construction takes place on concrete slabs, avoiding crawls. Your board sheathing is solid enough to build up, but not treated lumber. It may be one of the older southern pines that can be pretty rot resistant. In your situation, I would first re-nail, or screw all the boards to the joists. This may be a bit of a challenge, as old wood can be amazingly hard. You may find success with 2-1/2" deck screws, or #10 common nails. It may be so hard that only a nail gun will do the job. Next, you need to find a floor sheathing product by Huber lumber, it's called Advantech. It looks like OSB (chip board) but it is about the most water resistant stuff out there. It's heavy, hard on saw blades, and about as expensive as regular plywood. It comes with a fifty year structural guarantee, and it does not swell or delaminate. You probably won't have much luck landing the edges on floor joists, since many older buildings were not framed on exact 16" centers. I would install it with an air nailer, using 8D ring shank nails designed for installing subfloors. If you want to do a really solid job, you could use a belt sander, or floor sander, with a very aggressive belt, and grind the original boards clean. You could then both nail and use subfloor adhesive to bond the Advantech to the old board subfloor.  Advantech is a single ply subfloor, you can patch the joints and nail holes, and use the tiles you mentioned. Additional vapor barriers, used with an OSB or Advantech subflooring, might lead to rot, as the material is impermeable, and in effect it's own vapor barrier. You never want multiple vapor barriers in a situation like this.

Thanks for the advice, I have read a lot about advantec and it seems to be an awesome sub-flooring material and is probably what I'll end up using with your advice here.

Considering that I don't have a nail gun or air compressor, I was wondering why you nail it and if it would be possible to screw down the advantec?
Also, do I try nail/screw it along the floor joists or just into the other subfloor planks below?

paddedhat

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #27 on: January 28, 2016, 02:22:55 PM »

Thanks for the advice, I have read a lot about advantec and it seems to be an awesome sub-flooring material and is probably what I'll end up using with your advice here.

Considering that I don't have a nail gun or air compressor, I was wondering why you nail it and if it would be possible to screw down the advantec?
Also, do I try nail/screw it along the floor joists or just into the other subfloor planks below?

You might find that the floor joists and subfloor are simply too hard to screw into. As wood ages it can get amazingly hard. I recently helped a buddy build a loft in a barn. The joists were old pine 2x10s, salvaged from a 100+ year old church. They then spent two decades air drying in the barn. They were simply too hard to drive a screw, or hand nail into. We ended up shooting them with an air nailer, with the compressor running as high as we could pump it up. The only way you will know is to try it yourself. You might have no issues, or you might end up snapping half the screws you try to install. As for installing on the joists, like I said, it might work, but probably not. As a minimum, offset your joints between rows, by as much as possible.

lthenderson

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #28 on: January 28, 2016, 03:16:24 PM »

Thanks for the advice, I have read a lot about advantec and it seems to be an awesome sub-flooring material and is probably what I'll end up using with your advice here.

Considering that I don't have a nail gun or air compressor, I was wondering why you nail it and if it would be possible to screw down the advantec?
Also, do I try nail/screw it along the floor joists or just into the other subfloor planks below?

You might find that the floor joists and subfloor are simply too hard to screw into. As wood ages it can get amazingly hard. I recently helped a buddy build a loft in a barn. The joists were old pine 2x10s, salvaged from a 100+ year old church. They then spent two decades air drying in the barn. They were simply too hard to drive a screw, or hand nail into. We ended up shooting them with an air nailer, with the compressor running as high as we could pump it up. The only way you will know is to try it yourself. You might have no issues, or you might end up snapping half the screws you try to install. As for installing on the joists, like I said, it might work, but probably not. As a minimum, offset your joints between rows, by as much as possible.

Another way to get a screw or nail into old and very hard wood without a nail gun is to pre-drill it. It takes more time but is certainly doable.

paddedhat

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #29 on: January 28, 2016, 04:17:11 PM »

Thanks for the advice, I have read a lot about advantec and it seems to be an awesome sub-flooring material and is probably what I'll end up using with your advice here.

Considering that I don't have a nail gun or air compressor, I was wondering why you nail it and if it would be possible to screw down the advantec?
Also, do I try nail/screw it along the floor joists or just into the other subfloor planks below?

You might find that the floor joists and subfloor are simply too hard to screw into. As wood ages it can get amazingly hard. I recently helped a buddy build a loft in a barn. The joists were old pine 2x10s, salvaged from a 100+ year old church. They then spent two decades air drying in the barn. They were simply too hard to drive a screw, or hand nail into. We ended up shooting them with an air nailer, with the compressor running as high as we could pump it up. The only way you will know is to try it yourself. You might have no issues, or you might end up snapping half the screws you try to install. As for installing on the joists, like I said, it might work, but probably not. As a minimum, offset your joints between rows, by as much as possible.

Another way to get a screw or nail into old and very hard wood without a nail gun is to pre-drill it. It takes more time but is certainly doable.
Absolutely, and if you keep a battery drill and battery impact driver going at the same time, it really doesn't suck too bad.

MrSal

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #30 on: January 28, 2016, 05:16:50 PM »
Anything below the moisture barrier will be subjected to moisture and thus rot. If you add the moisture barrier above any wood, it will eventually rot. The reason your subfloor that you tore up was rotten in places may have been due to the lack of the moisture barrier. The wood may be pressure treated but even pressure treated wood rots in contact with moisture for long periods of time. I've replaced enough rotten sill plates and poles in pole barns to know that even if you use treated wood and subject it to moisture, you will eventually be replacing it.

It isn't pleasant sometimes dealing with crawl spaces but I think it is less pleasant doing something incorrectly and redoing it again and at considerable more expense.

Thanks for your comments and I get where your coming from, I really do, but just wanted to throw out some more thoughts before I decide that I may want to tackle this.

Almost no houses down here have encapsulated crawlspaces and the sub floor you see has been exposed to the crawlspace 'elements' for 58 years which includes awful exterior grading that causes water pool against the foundation wall and to pour under the house every time it rains (I am going to deal with drainage issue soon so this will significantly improve)

With that being said, the floor still seems structurally sound when I jump around on it even after all that time. So I'm wondering if i'm going to get a real return on investment with a crawl space encapsulation. When it comes time to sell I believe no one will care about the encapsulated crawl space. I honestly just need the installation to last till I no longer own the home which will more than likely be less than 15 years.

I really wanted to encapsulate the crawl space but after considering it and looking into what went into it, I had pretty much decided that if the house has stood for this long... it will probably last another 20 years.

What benefit will I see over the next 20 years if I encapsulate the crawl space and if I was not going to encapsulate it is there a second best option to protect at least some of the flooring layers in the kitchen?

What kind of insulation does your crawl space have? If you can put closed cell foam under the subfloor, that would serve as a moisture barrier between crawl space and home.

There is nothing down there just floor joists ==> subfloor ==> floors

Be it job great or small, do it right or not at all.  I'd be curious where else you'll cut corners in this remodel if I was a buyer.  Are you permitting this?

ETA: you have good answers here above.  You know what you have to do to make it right, correct, and safe.  Vapor barrier over the floor in the crawl, or closed cell foam underneath.

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would a house with a basement need barrier on the floor? my house has a basement and i was thinking of redoing some floors on the living space and i wonder then if a barrier would be need? or the fact that its a basement therefore it is elemnts isolated does not require one?

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #31 on: January 28, 2016, 06:30:40 PM »
I didn't read all the replies, but if it was my house, I would not worry about the vapor barrier.  I think you are correct in your assessment that if the moisture hasn't bothered your floor in 58 years, you are fine for the next 50, especially if you fix the drainage.

I don't get all the naysayers here - there is not just one best way to do something under all conditions.  I suspect the need for such a vapor barrier is regional.

Drifterrider

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Re: Where does moisture barrier go in floor and do I need one?
« Reply #32 on: February 01, 2016, 01:01:23 PM »
1.  Put down felt paper (think about the roll felt on your roof, under your shingles).  This stops airflow between the spaces in your sub-floor (the planks).  The felt paper works as a vapor barrier between under the house and inside the house. 
2.  What type of finished flooring are you going to use?  How thick is it?  If you are going with sheet goods you want quality underlayment.  Same for tile.