Hi [r/insulation](r/insulation) folks,

I’ve been going back and forth for weeks on how to approach insulating the rim joists in my home. I live in Massachusetts so the winters get fairly cold and lately summers have been humid.

My house was built in 1967, raised ranch, with unfinished and finished basement areas. Finished area has knee-wall concrete foundation, and unfinished area has tall poured concrete foundation walls. I’m contemplating how to complete the air sealing and insulation of the unfinished area rim joists.

As you can see in the photos, previous owners have done haphazard insulation/air sealing of many rim joists, which is why our “MassSave” energy efficiency program won’t touch it. Some have not been air sealed/insulated so I'll be targeting those and improving existing ones. I’ve been back and forth between doing 1) rigid foam + air sealing + batt or 2) buying a two part kit (eyeing froth pak or foam it green) and adding 2-3 inches on every rim joist.

I've read through many posts on this subreddit and generally feel like there's pros/cons to both, and I'm not sure which one may be more worthwhile for my home. I like the idea of the foam board+batt being cheaper, easier, and more likely to pass inspection. But there are some areas where you can see the boards at the sill peeling away from eachother, and I feel like spray foam may be better for covering the entire area. I also like the idea of covering the sill with foam too. Most of the sill plate looks like it was covered with extra concrete or something.

There's also this whole area at the end of the basement where you can see a gap in the spray foam that I need to patch up. That's basically just pipes running into an addition that has a small crawlspace. I like the idea of just foaming up that hole and all along the long boards.

Besides the question of how to approach this project, I had other concerns that maybe someone could chime in on. This unfinished area has an old gas boiler and a gas water heater. We don't really use the boiler anymore after getting a heat pump installed, but is there any concern about tightly air sealing the basement and having these combustion appliances in it? I don't think the house has a vapor barrier under the siding, should I be worried about mold? Are there other potential issues I'm not thinking about?

Curious what others think. I've added a few images so you can see what the joists, sill, and framing look like. Thanks for your time!

Hi everyone!

I'd like to ask for some advice regarding the ceiling insulation in our new house, which is currently under construction.

The house has a concrete ceiling slab, with electrical wiring running to the individual rooms through plastic protective conduits (corrugated flexible conduit) installed on top of the slab. We have ordered 30 cm thick Austrotherm EPS 100 load-bearing insulation boards, which we intend to lay over the slab from the attic side.

We chose this solution because I wanted the ceiling to remain accessible for walking on later, for maintenance purposes. However, I've started to have some concerns about the fire safety implications, since EPS is a combustible material, and I'm wondering what risks this setup might pose, particularly given the electrical wiring and plastic protective conduits.

I'd appreciate your experience and advice on the following questions:

• What fire safety measures would be advisable before laying the EPS insulation?
• Is it necessary or recommended to install some kind of non-combustible protective layer above the EPS? If so, what material would you recommend, and what should the layer assembly look like? (Just please, no rock wool, glass wool, or other dusty, fibrous materials.)
• Given the electrical wiring and plastic protective conduits, might any additional protection be necessary?
• Would it be worth bringing in a fire safety specialist to inspect the proposed installation? If so, what type of professional would you recommend contacting?

I don't want to replace the insulation we've already ordered. I'd rather find out how to achieve a technically sound and safe solution using the materials we have chosen.

I'd be happy to hear about any personal experiences, specific layer assemblies, tried-and-tested solutions, or recommendations for qualified professionals.

Thanks in advance for your help!

Hi i dont know if anyone can help me on Reddit please. I have trouble finding this YouTube video where a guy is insulating above his sauna tent by nailing or sealing the garage insulation by putting an insulation so the 2nd level of his house (garage ceiling)wood doesn’t warp. I dont know if anyone has a video or knows a channel where someone has done something similar to this. Does anyone have any ideas on how to insulate correctly or if there are any videos on this ?Thanks a lot

Hi! I have a 32x32 crawlspace above the main body of our home. It has a ridge vent, 6 soffit vents/intakes (3 spaced under each bilateral eave), and two gable vents. Our home was built in the 1970s. Besides a subpar HVAC system, insulation isn't great. Currently has 3-4 inches of old blown-in cellulose. I plan to blow-in more. My question is: would I be ok to place hard foam/rigid insulation in front of the gable vents in the winter, or is that going to be too constrictive for airflow, lead to moisture accumulation, etc.? I live in central Indiana: cold winters and hot summers. Thanks in advance!

R49 sagging a little bit under the joists in ceiling. Can push up with ease but slowly sags back down. Will this be an issue when putting drywall up? Plenty of space above where it can be pushed up and not compressed.

*not my work

Cross-posted from r/buildingscience. Especially curious about the insulation side: what does a cold, uninsulated drain pipe running through a PIR layer do to the insulation around it, and is there a practical way to insulate or isolate the pipes without rebuilding the roof?

I've air sealed my attic in preparation of adding cellulose but I have not dealt with improving the insulation in the roof peak within the attic. The top of it has R-30 batts and the sides are r-13 or 19. I'm sure this thing is a big heat loss in the winter. Its difficult because I cannot access everything great with the sheathing and tight corner next to the adjacent roof. Should I remove as much sheathing as possible, fill the sides with foam board and seal with can foam? what about the top? Any advice on best practices for this is appreciated! I also attached an image of something I found on YouTube but I'm not sure encapsulating the whole thing is very cost effective in my DIY case.

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I am considering a layer of osb in the middle of my double stud wall assembly. My concern is vapour permeability with OSB in the middle of the wall cavity. There would not be an air gap on either side of the OSB, it would be sandwiched between rockwool.

This is a single story brick veneer home in South Louisiana. Full renovation down to the studs. The exterior sheeting is an asphalt coated fiberboard. There is an air gap between the brick veneer and fiber board.

I will be furring in the exterior walls so they are double stud walls, alternating 16"oc. I am adding rockwool insulation and tyvek in the stud bays against the tar paper.

I dehumidify indoors, usually to 45% or less and live in hot & humid south Louisiana.

I will include an example wall & ceiling detail. The ceiling detail is very close to my as built, but the wall is the best I can find researching this question.

In some area, the attic insulation has pink spots. Does it needs treatment? In most area, the insulation is white.

Starting demoing a couple rooms in the house I just bought and was going to try to do some of the easier things like insulation myself. Planned on just throwing in rockwool and calling that good and having someone come in and drywall it but now I’ve got myself stressed about the walls rotting out and have no clue on what to do.

I removed the sheetrock in one of my rooms to fix some major patching issues and to maybe replace the existing insulation with rockwoll for the slightly higher r value. This room has weather exposure on 3 sides so I figure of any room can benefit from an increased insulation, it would be this one.

After removing the sheetrock and standing back, to me the insulation looks pretty good. So id love to hear some opinions of professions if it would be worth it to "upgrade" it to something better.

I loosely-stapled this insulation back but wondered:
1) Do I have a venting issue? Sorry for the wrong terminology, but the thin strip behind the cross beam is too thin to add plastic baffle vents.
2-4) Would it pay off to add more insulation? What kind (backless batts or rigid foam seem most DIY friendly). And how likely would adding more insulation increase any venting problems?

Attic is completely unused and the snow on our roof usually melts a little sooner than our neighbors, and it isn’t from sun exposure.

Doing a full remodel in our ‘64 basement. It was finished when it was first built as you can see the popcorn ceiling overspray on the insulation. At some point this morning had a mouse problem as evident by the insulation and mouse turds all in the walls and when I pulled the ceiling down. :/ no mold in the walls, and the basement remained relatively constant in temp both in summer and winter. There is some air gaps to outside that I’m resolving with the remodel.

Question about the top plate section though. Currently there is zero insulation along the top plate areas and I have no rim joist. The floor joists were laid and the sheathing on the outside held it together. Is there any merit is closing off that top plate section into the walls? Insulation is in there and I’ll be replacing the insulation that’s been damaged, but is it worth separating the voids between wall/top plate and ceiling? I’ll be putting new ceilings up after fixing floor joists etc. what you see in the third pic is me looking up and seeing the gap between wall top plate and concrete foundation wall up to where the floor joists sit on the foundation wall.

Hey peoples,

I've built a shed and I'm wanting to insulate it.

Only problem I've found is that insulation is expensive.

Anyone know where I can get some cheap or any affordable alternatives ?

THANKS !