Insulating spare bedroom (used to be a porch)

[LibrarIan]

I have a room above a one-car garage that used to be a porch. Years ago, someone finished the room and turned it into a bedroom. However, they did a very poor job. The room is freezing all the time.

Here is what I plan to do

• Remove super thin crappy wall paneling and tear out the minimal insulation
• Add adequate wall insulation
• The ceiling is actually drywalled, but with no insulation. I'm going to drop the ceiling down and insulate
• Drywall the whole room
• Insulate the floor in some way

All that being said, I have questions about what kind of insulation I should buy. For a general idea of the room, it's about 140 square feet and two sides are exterior. I live in northern Kentucky.

For the walls, I know I need insulation of R value 13-15 (I have 2x4 framing). What I'm not sure about is if I need it faced or unfaced. I've seen other people use faced insulation along exterior walls, but when I was checking out some videos online I saw a lot of people using unfaced. What's better?

For the ceiling, the R value recommendation seems more difficult to find. I'm finding a lot of stuff about attics (already did that project), but not for just the ceiling of a room, like in an addition. Also, I have a limitation - Instead of ripping out the existing ceiling, someone recommended I simply drop it down by adding some 2x4s across the ceiling, insulating that area, then drywalling over it. However, in order to maximize the height of the room, it was also recommended to turn the 2x4s so that they're flat instead of on their sides. Given that there is a smaller depth to work with, how much does this change the type of insulation I can put it? And also - faced or unfaced?

For the floor, I see recommendations online for R values of 25-30 for floors. I don't know what kind of material that would go under your floor would achieve that R rating. This is a room above a garage, so I don't have a lot of depth to work with. What would be best to do for the floor to stave off the cold from the garage below?

[Endo1030]

polyiso foam would give you the most r-value that I can think of among DIY options.  It is 5.6 per inch.  That still isn't going to give you very much if you use 2X4s on the ceiling.  But you have to consider the ceiling height for code as well as r-value.  You didn't mention the current height of the ceiling.  Is there any attic space above the ceiling? If so, maybe you could cut an opening in the drywall and blow in insulation.  They don't make batts for a 1.5" space, if you were to install 2X4's on their side on the ceiling. 

Your plan with the walls sounds fine.  I would just use unfaced batts to avoid complication.  I would actually use rockwool batts if it were me.

You can put down polyiso on the floor and add a suitable flooring material on top.  but you'll lose a lot of room height, and might make an awkward step up from the next room.  Are you parking a car in the garage or using it for anything other than storage?  if not maybe you could replace the garage door with something more airtight and insulate that space, then you can leave the floor as it is.

My impression without having a lot of information is that this is going to end up an awkward space if you go through with your plan, so you might want to weigh the cost with the end result.  Are you planning to get a permit?  Did they add HVAC ducts and electrical to the room already when they did the first renovation? 

[LibrarIan]

@Endo1030

The current height of the ceiling is 100.5 inches. The idea to put the ceiling 2x4s flat doesn't sound good to me. If we put them up normally, the height of the ceiling with drywall would be about 96.5 inches or so, or still over 8 feet. This is adequate for building codes. There is no attic space above the room.

So with the 2x4s affixed normally, faced or unfaced for the ceiling?

Regarding the floor, I suspect there is more room to grow downwards. Most times with a porch, you walk out and step down at least a step or so. I have a feeling there is space I can use. I'm just not sure yet because I haven't removed to the floor. If I'm right, I think I'll be good on not messing with room height here.

We do not use the garage for a car, but we do use it as a shed, keeping things like the mower or other tools. I intend to keep the garage door that's there, but to address its floor and side seals, as well as adding insulation to the door itself and the ceiling of the garage.

There is no ductwork in this room, but there is electric already run. I am not getting a permit.

[Telecaster]

The facing goes towards the side that is normally warm.   The idea is that you don't want warm, moisture laden air traveling through the batt and getting trapped. 

Although I have carpenter friend who is really, really knowledgeable who thinks unfaced performs better, so there's that. 

DOE of energy has recommendations for ceiling insulation R-value based on your location.  A bit of Google work might help.

If you don't have a lot of space in the ceiling, spray-on foam has a high R-value, but it is expensive.  Next you could go with foil-faced foam batts.  Again, more expensive than fiberglass, but more R-value per inch. 

[uniwelder]

OP, you had already asked about insulating the floor recently in another posting---https://forum.mrmoneymustache.com/do-it-yourself-forum!/insulation-for-a-room-above-a-garage-with-a-concrete-ceiling/

You ended up with a lot of recommendations, but not sure what you ended up deciding.  It also seemed from that posting there was no room to build up the level of the floor.  That the concrete floor of that room was at the level of the rest of your house.  If you do have a step down into the room, then the easy answer, which would have helped a lot in your other posting, would be to lay down some foam sheets with some 2x4's embedded between and put a subfloor over top of that.

For your current posting, if you can't get insulation in the attic space for some reason, perhaps you can sandwich 2" of foam between the current drywall and new drywall sheets.  Glue the foam up, glue the new drywall to the foam, secure with some 4" long screws.  You'd probably have trouble aiming into wood with all that thickness, but the glue will do most of the attachment for you, so the screws aren't as critical.

edited to add--- what exactly is above this room?  I looked at the photo you have from your other posting and it looks like a roof overhang in one pic.  Just a little glimpse, so not quite sure.

[Endo1030]

I'm not great with understanding building codes, but assuming you're climate zone 4, the 2012 building code requires R-38 for ceilings, R-19 for floors, and R-15 for walls.  You're not getting a permit, but you could still take those recommendations as a minimum guide for what will be comfortable/efficient.  You won't be able to hit R-38 at the ceiling with just 2X4's. 

And it would also be a good idea to understand how the roof/ceiling is built. What slope is the roof? I assume the ceiling is not sloped based on your description.  there must be some space between them.  How is that vented?  if you have moist air reaching that space from the house and it is not vented properly you may be setting yourself up for condensation/mold problems by insulating that ceiling.  In other words heat transfer from inside may be keeping it warm enough to avoid condensation, and if you take that away...

[nereo]

Before you ever get to insulation, I’d carefully examine if the space has been properly air sealed. If the work was as shoddily done as you indicate there’s likely a great deal of air leakage, and no amount of batts is going to make a leaky room warm.

Pictures would go a great deal here.  From what you describe you have very little space to work with - if so your best bet is likely closed cell (2llb) spray foam for the walls and possibly the ceiling as well.  Get quotes.  If you are willing you can do the job yourself with froth-packs, but it may or may not be cheaper than hiring out (depends on the total square footage - you mentioned 140sqft but only 2 walls are exterior.

As for the floor - you said the room is above a garage?  If possible I’d insulate from the garage side (as in, from the garage ceiling).  Cheapest option will be to use rigid foam across the joists (dropping as necessary) and blown cellulose between.

[LibrarIan]

For those asking for pictures, here is an Imgur collection: https://imgur.com/a/Sl0DNiW

A few things to note about the pictures:

Hopefully it's apparent from the picture of the rear of the house (room in question is all the way on the right) that there is no attic space above this room. I haven't dismantled the existing ceiling and don't plan to, but based on the roof line outside I'd say it goes interior ceiling > framing/structure > roof (which is a rubber roof). Seems kind of just like a regular wall but on top of the room instead of on the side.

Also, the room is a disaster zone right now. There used to be carpet on the floor, but the prior owner's dog used it as a potty mat and we had to tear it all up. What you're seeing is a plastic sheet that is resting on top of masonite, plus junk that has accumulated in there while we figure out what to do with the room.

Also a shot of the panel board used on the walls. I have torn back a spot where there was a seam and this stuff is like 2 mm thick. There is insulation behind it, but it's very thin and doesn't even fill in the 2x4 framing (there are gaps all around the sides, etc.).

The two side windows are currently single-pane aluminum and are being replaced with double pane. The window AC unit is going and we are installing a small floor unit. As for room heat, the guy who is going to do our drywall suggested this: https://www.radiantsystemsinc.com/. Not sure if I'm into it though.

At the threshold of the room, I tore up some of the masonite and it looks like there is plywood beneath that. Under the plywood? I don't know yet. Hopefully a bit more space to work with.

@Telecaster @Endo1030 - DOE guides don't seem to call out just a plain old ceiling specifically, instead referring to what needs to go in an attic (R38 in my case). I don't have attic space here. What you see is what I get.

@uniwelder - I did ask a question about this before. In that post, I was trying to learn more about someone's recommendation to me to insulate the roof of the garage below instead of doing any insulation to the floor of the room. I got a lot of conflicting info. In the end, I decided I'd try to put some foam insulation on the ceiling of the garage, but additionally try to add floor insulation. It seems like the R value desired in my region for floors (R25-30) seems potentially not attainable depending on what's beneath the plywood.

@nereo - I will look into air sealing for sure.

[Paper Chaser]

Think of the recommended R values as being for "overhead insulation" instead of "for ceilings". It doesn't matter if there's only 6 inches of depth to fit that insulation because you have a flat roof or or if there's 100 ft of empty overhead depth to fill. The recommended R value is the recommended R value so don't get hung up because it says "for ceilings". They're talking about any overhead space with a roof on the other side.

Now obviously, there are constraints to achieving that recommended R value, with space being a big factor. Really, flat roofs suck for a number of reasons, so if it were my house I'd try to add some depth to the ceiling for insulation and reframe the roof structure there at the same time to eliminate the flat rubber roof. You could do a single pitched "shed" roof pretty easily that would be higher next to the house, and lowest at the outer wall. You could also do actual pitched trusses which could give you an actual attic for extra storage and more space for insulation at the same time. Either of those options will increase the budget, but they're probably the best way to get a decent end result here. If you want the best end result, then redoing the roof structure  to eliminate the flat roof and add space for more insulation is the best route not only for comfort but also for a better performing roof and potentially more storage.

Insulation types:
Closed cell spray foam is the best. It air seals, insulates with a high R value, and provides it's own vapor barrier at the same time (when applied 3" thick or more). This could also theoretically be applied directly to the roof of the garage in whatever amount of space is there, so that the floor is insulated too. It's great for irregular spaces. The downsides are that it's not really DIY friendly and it's costly. If you've got very limited space to fit insulation, it's the best option. But it's really not cost effective when you start applying more than 3-4 inches of depth as the outer 2-3 inches do almost all of the air sealing and insulating work.

Rigid foam panels are a close second that are more DIY friendly. I'd look for the Polyiso kind since it's the same foam as closed cell spray foam. You can cut them to fit tightly between framing with super basic tools, and if you want to go the extra mile you can use cans of spray foam to seal the edges. It's great at reducing drafts and gives lots of R value per inch of thickness. You can often find these panels on local CL type sites for a fraction of what the box stores sell it for.

Batts are common and the cheapest option. Very DIY'able. They're also the least effective insulation. They do little or nothing to stop drafts, and they have lower R value/inch than the foams.

Blown in cellulose is the cheapest option per inch of thickness, but you need a lot of it so it's only really a good option if you're reframing the roof to have a bunch of attic space above. But it could give you the recommended overhead R value for the least amount of money relative to the other insulation types.

So again, if it were mine, I'd really think about redoing the roof framing over that room to add some overhead space and get rid of the flat rubber roof at the same time. That will probably give you the best end result in a number of different aspects.
If that's too much, and you're sticking with retrofitting the existing envelope then I'd tear that whole room down to the framing to see what's actually there, move any plumbing/electrical that you want to, and then add as much closed cell polyiso foam as I could fit in a given space (whether via rigid panels/DIY, or just paying to have it professionally sprayed). Batt insulation would only be a last resort for me, especially if you won't be able to get to the recommended R values for other parts of that room.

For your question about vapor barriers, the vapor barrier typically goes on the side of the wall that is warm most of the time. If it's a cold climate, that would be to the inside of the insulation, and if it's a warm climate it would be to the outside. In zone 4 where you are, it's a bit of a toss up. And if you use closed cell foam, then you don't have to worry about it.

[Endo1030]

One issue is that the top of the window looks like it is already basically at the top of the wall.  If you lower the ceiling have you thought about how that detail is going to go?  I don't see any reason why you should leave the drywall on the ceiling in place.  It won't be hard to pull it down, then you can put insulation in the framing up there.  Although it still looks like it is no more than a 2X6 cavity. 

As paper said, that flat roof isn't a very good thing.  I'd even be worried in a downpour that a lot of water could back up against the main house, so I hope there is some real good flashing at that junction.  A sloped shed roof would look a lot better and be more functional. 

[LibrarIan]

Quick update - my wife and I pulled back the plywood a bit and it is indeed an old step-down porch. We should have plenty of room to insulate the floor. Additionally, it looks like the builders of this addition did put in some kind of (yet unidentified) fluffy looking insulation beneath the plywood. It's not helping, but at least they tried.

[LibrarIan]

One issue is that the top of the window looks like it is already basically at the top of the wall.  If you lower the ceiling have you thought about how that detail is going to go?  I don't see any reason why you should leave the drywall on the ceiling in place.  It won't be hard to pull it down, then you can put insulation in the framing up there.  Although it still looks like it is no more than a 2X6 cavity. 

As paper said, that flat roof isn't a very good thing.  I'd even be worried in a downpour that a lot of water could back up against the main house, so I hope there is some real good flashing at that junction.  A sloped shed roof would look a lot better and be more functional.

One reason we were reluctant to do this is because the addition was built in/around 1970. At that point in time, drywall and drywall mud commonly contained asbestos. We could get it tested of course, but if we needed to remove it there would be a lot of drama surrounding the removal.

[Endo1030]

Getting it tested for asbestos is pretty painless.  The kits cost 20-30 dollars, you just cut out a sample and mail it in.  I'd at least verify that before I ruled it out.  Congrats on finding space in the floor.

[Telecaster]

One reason we were reluctant to do this is because the addition was built in/around 1970. At that point in time, drywall and drywall mud commonly contained asbestos. We could get it tested of course, but if we needed to remove it there would be a lot of drama surrounding the removal.

It is not that big of a deal.  Testing it is easy, just cut piece the size of thumb, put in a baggie and take to a lab near you.  Or you can ship it as well.  The issue with asbestos is that it is dangerous if it is loose and blowing around and therefore breathable.  It is pretty easy to keep the work surfaces wet with with a garden sprayer.  Put a little spirt of Elmer's glue in there too, if you like.  Not only does that keep the fibers from blowing around, water causes the asbestos fibers to curl so they are less dangerous.  Obviously, you want to use appropriate PPE.  Ideally a fitted respirator.    Try to keep negative air pressure, e.g. a fan that vents to the outside and block off the rest of the house with plastic. 

Obviously, you want to be smart, but keep in mind basically everything from the 1930s to the 1980s was loaded with asbestos.  The main victims of asbestos were shipyard workers, miners, and asbestos product manufacturers who were breathing that stuff all the time.   Smoking seems to really exacerbate the danger.  But there is little evidence that incidental contact causes serious health issues.  Again, be smart but not paranoid. 

I'm a certified asbestos inspector by the way.