A lot of boats have been taken out by wet foam. Since I posted what I did above, I talked to another guy, a GC, who said he had to remove a foam filled wall recently because of a leak. I haven't heard anything about the insurance companies not liking it, but it hasn't been a commonly used insulation in my area until the last 5 years or so, but it's still probably the least used method around here.
Wall Insulation Recommendations
- Thread starter tworley
- Start date
A lot of boats have been taken out by wet foam. Since I posted what I did above, I talked to another guy, a GC, who said he had to remove a foam filled wall recently because of a leak. I haven't heard anything about the insurance companies not liking it, but it hasn't been a commonly used insulation in my area until the last 5 years or so, but it's still probably the least used method around here.
I build one off boats as a hobby and according to USCG rules, they must have enough floatation not to sink. The recommend the two part por in foam (same stuff as spray foam). It took me quite a while to get a skiff I built certified because I created air tight chambers and said they were floatation. They asked what about an impact and penetration of the chambers. I showed them the pictures of the soda bottles and pool noodles filling the chambers. I even demonstrated to them that my floatation far exceeded their rules by mine floating right side up even when completely filled with water.
I have never seen a boat which contained expanding foam where the foam did not get water logged and was the majority reason for the destruction of the craft.
I would rather staple plastic to both sides of the 2x4's and call it good before I would put in spray foam. In 2010 we had the Chinese drywall crisis, spray foam will be the next one.
Interesting. I’ve not heard of that in Michigan yet. I’m not worried about it in my barn, since it’s not stick built (pole).
I’ve heard a bit about it sealing buildings up too tight, and then they can’t breathe. That causes an issue too. Here, i think the ideal solution is probably to spray the roof, and do blown in Cellulose for the walls. I’m not a big fan of blown in for the roof/ceiling, just because you have to build it up so far, then it settles over time….and you lose R-value
A few years ago we had a few "certified green" houses, and one whole subdivision, popup around here. They had to meet a certain air door tightness threshold as part of their "certification". I was told those houses were being built so tight that they had to have a special external air exchanger that would cycle in and out a certain amount of air on a schedule. I asked one GC what happens when the power goes out and stays out for a while, how will the air cycle. He took a few seconds and said they better open the door or a window. The generic homeowner is too stupid to figure that out.
I'm interested to see how those houses fair after 20 years.
A few years ago we had a few "certified green" houses, and one whole subdivision, popup around here. They had to meet a certain air door tightness threshold as part of their "certification". I was told those houses were being built so tight that they had to have a special external air exchanger that would cycle in and out a certain amount of air on a schedule. I asked one GC what happens when the power goes out and stays out for a while, how will the air cycle. He took a few seconds and said they better open the door or a window. The generic homeowner is too stupid to figure that out.
They are building them so tight and in order to meet the highest certification level they have to use ventless clothes dryers because a vented one uses approx 200 cfm and that will disqualify them.
I just want a house built with exceptional quality, withstand any hurricane that comes along, using whatever materials to make that happen because I do not care what my electric bill is. When you live in a big house there comes a point where certain things are of zero consequences and the electricity is on that list.
A few years ago we had a few "certified green" houses, and one whole subdivision, popup around here. They had to meet a certain air door tightness threshold as part of their "certification". I was told those houses were being built so tight that they had to have a special external air exchanger that would cycle in and out a certain amount of air on a schedule. I asked one GC what happens when the power goes out and stays out for a while, how will the air cycle. He took a few seconds and said they better open the door or a window. The generic homeowner is too stupid to figure that out.
These foam Lego blocks that are filled with concrete intrigues me. I need to do more research on them (insulated concrete form).
We looked into ICF when we built our cabin. The ~R50 walls was of interest, but the "thermal mass" was a downer for a structure only heated on weekends. It would take a couple days to get the walls up to temp, but once there, it took little energy to keep heated. We did use ICF for the basement walls, and added a small gas furnace.
Another thing that concerned me was termites. If you're in a termite prone area, it seemed the foam outer layer concealed any termite activity, and provided easy movements between floor levels.
When we built, pre-covid, we were quoted about a 10% higher cost of construction compared to regular stick built walls.
If I were building again, and planned on keeping it heated or cooled 24/7, I would consider ICF. A local Fox Blocks dealer did our basement walls.
https://www.foxblocks.com/
I'm a building contractor, FWIW. I primarily build post frames (where Rockwool really shines), but I do plenty of stick framing as well. Rockwool is a great option. Much easier to work with and fill gaps than fiberglass. It's worth the extra cost, IMO. It definitely cannot be cut or trimmed with a butter knife. Best cutting tool I've found is a long, fine tooth sawzall blade mounted in a handle for manual use. They do make knives specifically for the purpose but you're not going to be able to find those at any normal hardware store. For long cuts, a table saw works well, as long as it's either outside or has a vacuum attached to it. If you use a table saw, set the blade so that it's just barely below the surface of the insulation so it doesn't spray the dust into the air.
It's not possible to get R19 with fiberglass or Rockwool in a 2x4 wall. You'd have to have closed cell foam.
I guess to close out the thread, I bought 6 bags of the R15 rockwool at Lowes (post 19) and went to work.
I did originally use a slightly serrated butter knife and while it did cut, I ended up using a rasping saw which was faster.
I have 9 batts left. I'll cut them up and use them in the rim joists in our unfinished basement on top of the already existing fiberglass (which is poorly placed anyway).
Since completing both walls, the garage hasn't dipped below 54°, though we haven't really had a cold snap yet. Coldest outside temps have been in the high 20s.
I did originally use a slightly serrated butter knife and while it did cut, I ended up using a rasping saw which was faster.
I have 9 batts left. I'll cut them up and use them in the rim joists in our unfinished basement on top of the already existing fiberglass (which is poorly placed anyway).
Since completing both walls, the garage hasn't dipped below 54°, though we haven't really had a cold snap yet. Coldest outside temps have been in the high 20s.
Similar threads
