Author Topic: Foam Board Insulation in Basements  (Read 885 times)

accolay

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Foam Board Insulation in Basements
« on: January 26, 2018, 04:51:08 PM »
Why do we glue or otherwise attach foam board to the concrete walls in basements? What's the reasoning? Is it to make sure there is no air space behind them? Doesn't the stud wall hold them in well enough?

big_owl

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Re: Foam Board Insulation in Basements
« Reply #1 on: January 27, 2018, 05:44:23 AM »
I believe it was to prevent the warm air inside your insulated basement from seeping behind the foam and coming into contact with the cold concrete...and condensing.

It's a pain in the ass to glue it on no doubt, it took me a special system to get it to dry without falling off.

ETA your stud wall isn't going to be tight up against every single wall in the basement.
« Last Edit: January 27, 2018, 05:46:47 AM by big_owl »

Fishindude

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Re: Foam Board Insulation in Basements
« Reply #2 on: January 28, 2018, 04:50:29 PM »
If you have good, dry conditions there really isn't a need for it unless your basement walls extend well above the ground level.
There are a whole lot of perfectly functional basements out there with exposed concrete or concrete block walls.

aerofreaky`

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Re: Foam Board Insulation in Basements
« Reply #3 on: February 03, 2018, 12:41:19 PM »
Here's an example of what you might be looking to do. Notice in the first photo that the wall was frozen with moisture. I used  heat gun to transpire the moisture away. I placed R10 2" thick closed cell foam with proper (like packing tape) at the seams held up with an adhesive especially made for foam board. Then, I stud the wall and placed temporary jigs to pressure the foam board equally against the wall until the glue dried. Then, I put a r13 in the 2x4 wall and covered it with 1/2 GWB.  This is a fairly expensive project material wise. The 2x8 sheets of DOW are not cheap...nor is the fiberglass bats...

aerofreaky`

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Re: Foam Board Insulation in Basements
« Reply #4 on: February 03, 2018, 12:42:29 PM »
more photos, maxed out size of files...

accolay

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Re: Foam Board Insulation in Basements
« Reply #5 on: February 05, 2018, 09:56:50 AM »
Thanks for the replies. I'm trying to finish a basement bedroom, so I think I may just do that one room, and possibly that as the only finished room. The basement is fairly small and unsure it warrants a completely finished area.

Accidental Miser

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Re: Foam Board Insulation in Basements
« Reply #6 on: February 05, 2018, 10:01:52 AM »
I used insofast insulation for my basement walls.  It worked great.  More expensive but worth the time savings to me.

www.insofast.com

I have no connection with the company, by the way, just a happy customer.

accolay

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Re: Foam Board Insulation in Basements
« Reply #7 on: February 05, 2018, 10:05:48 AM »
I used insofast insulation for my basement walls.

So then you don't have to use 2x4 studs, drywall or other such covering?

lthenderson

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Re: Foam Board Insulation in Basements
« Reply #8 on: February 05, 2018, 10:18:35 AM »
Thanks for the replies. I'm trying to finish a basement bedroom, so I think I may just do that one room, and possibly that as the only finished room. The basement is fairly small and unsure it warrants a completely finished area.

Make sure you apply any adhesive in vertical rows that don't connect on the bottom. This is a common mistake I see others make. In the future if water does fine its way between the concrete and the foam and you applied the glue in large horizontal zig zags as people tend to do, you end up with a moldy pond behind your foam and hides a problem until even more damage occurs. It is much better for it to drain down the wall and underneath the sill plate (should always use treated for this reason) so you can see there is an issue and fix it.

accolay

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Re: Foam Board Insulation in Basements
« Reply #9 on: February 05, 2018, 10:33:19 AM »
Make sure you apply any adhesive in vertical rows that don't connect on the bottom. This is a common mistake I see others make.

I have read this tip, but thanks for posting it anyway. It's fairly amazing how many how-to videos and instruction there are out there, but many fail to list these important tid bits.

big_owl

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Re: Foam Board Insulation in Basements
« Reply #10 on: February 05, 2018, 12:57:35 PM »
Make sure you apply any adhesive in vertical rows that don't connect on the bottom. This is a common mistake I see others make.

I have read this tip, but thanks for posting it anyway. It's fairly amazing how many how-to videos and instruction there are out there, but many fail to list these important tid bits.

I have a whole bunch of pics in this thread of how we installed our foam insulation and walls in our own basement finishing project:

https://forum.mrmoneymustache.com/share-your-badassity/from-zero-to-million-dollar-basement-(diy)/


accolay

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Re: Foam Board Insulation in Basements
« Reply #11 on: February 05, 2018, 09:31:41 PM »
That's cool, dude. Hopefully the finished room will look half that good when finished.

What if I build the wall on the ground prior to gluing the foam board then put it into place to hold everything together?

big_owl

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Re: Foam Board Insulation in Basements
« Reply #12 on: February 06, 2018, 08:46:55 AM »
That's cool, dude. Hopefully the finished room will look half that good when finished.

What if I build the wall on the ground prior to gluing the foam board then put it into place to hold everything together?

I guess that would work too, if you had all your walls pre-fit beforehand.  All your walls will need to be tight up against the concrete though.  In my experience that isn't possible except for maybe a small area.  Depends on the dimensions and build of your basement and how you intend to finish it.


Bradfurd

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Re: Foam Board Insulation in Basements
« Reply #13 on: February 07, 2018, 12:04:41 PM »
I used insofast insulation for my basement walls.

So then you don't have to use 2x4 studs, drywall or other such covering?

The studs are built in to the insulated panel, but you would still hang and finish drywall to those integral studs for a true finished look.

couponvan

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Re: Foam Board Insulation in Basements
« Reply #14 on: February 21, 2018, 11:58:25 AM »
I used insofast insulation for my basement walls.  It worked great.  More expensive but worth the time savings to me.

www.insofast.com

I have no connection with the company, by the way, just a happy customer.
@Accidental Miser - How long did it actually take you to do it? Which version did you use? I've been looking and looking and looking at this company. I am in the Midwest, and think I want to go this route. How was shipping/delivery?
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