Insulating a 100 yr old home, no sheathing

[masraum]

We've got an old wood frame pier and beam home that was built by the original owner a hundred years ago. We're working on it and in many places/cases will have access inside the walls. I've discovered that insulation is spotty at best. I think all of it is <30 years old, but there's just not much of it.

We've got the bathroom gutted. From inside the bathroom, I can see to outside at the bottom of the walls. I was thinking that running some caulk down the cracks, but then I thought that it might be easier to run some low expansion "Great Stuff" (foam in a can) in that area. What do you guys think.

I'm also going to pull some of the shiplap, put in f/g bat insulation and then put the shiplap back unless someone has some other genius idea that is better/easier. On interior walls where there's plumbing, should I put insulation around the plumbing as an extra safety precaution? We had no frozen/broken pipes inside the house last year (mostly PVC, a little copper, new/remodel stuff is all pex).

The bathroom looks a little different now. The old plumbing has been removed and new plumbing put in place, but the important part is where you can see light at the bottom of the walls (red square), and the confusing insulation in the yellow square.
On the west wall (left side of the pic) left of the window (not in the pic) there's some insulation at the top of the wall, but it only comes part way down. But in the portion of the pic that you can see, the insulation seems to be in the middle of the wall, but does not extend to the top of the wall. I also don't see any insulation on the north facing wall, but I suppose it's possible that there's some there that I just can't see. Of course, none of the insulation made it to the bottom of the wall. (what I'd love to do is pull all of the siding, insulate, add sheathing and then put new siding on, but that's not in the cards, at least, not currently).



I'm talking about something like this (to seal the gap)


NOT this...

[ckelly78z]

One of the best things I did when completely gutting, and rebuilding both bathrooms in our house was to insulate each wall (even interior walls) along with the floors, and ceiling to have a warmer, and quieter bathroom.

Expanding foam in those cracks will cut down on drafts.

[masraum]

That's what I've been thinking. This house is old and not very efficient. My plan is to insulate as we go. I'll insulate the attic too.

Someone sprayed the bottom of the house with spray foam, but they did a horrible job. I don't think there's a 1/4" of coverage and that would be an improvement (vapor barrier) except that it's not remotely a full coverage. It may be better than nothing, but not by much.

Interesting, interior walls too. OK.

I was thinking the foam would be better and shouldn't be much of a downside.

[Bill Douglas]

Steve, I had an old house like that. If I pulled the shiplap off to insulate it properly the place would have fallen to bits. As per yours I pulled the bottom one or two shiplap boards off and stuffed pink batts (ordinary in wall insulating) in there to stop the air flow from under the house racing up the walls and into the ceiling space then out. It created a static air pocket that really did work. I put up sheets of drywall which insulated too. It was quite a warm house after that.

Not a perfect solution, but one that worked.

[masraum]

Originally Posted by Bill Douglas

Steve, I had an old house like that. If I pulled the shiplap off to insulate it properly the place would have fallen to bits. As per yours I pulled the bottom one or two shiplap boards off and stuffed pink batts (ordinary in wall insulating) in there to stop the air flow from under the house racing up the walls and into the ceiling space then out. It created a static air pocket that really did work. I put up sheets of drywall which insulated too. It was quite a warm house after that.

Not a perfect solution, but one that worked.

Yeah, our house does have drywall. I've pulled all of the drywall in this room, but will be putting it back. Having the drywall made a huge difference, so we're looking forward to putting it back (plus insulation). This is now the coldest room in the house on cold mornings.

[Instrument 41]

I have done 3 houses built before 1900. All of the same construction. One of the things we did when I hade it sprayed with Closed cell foam insulation from the bottom is not just in between the beams but also along the outer perimeter so that you don't have to stuff the voids with pink insulation. When you would look under the house it was completely covered on foam. The closed cell is almost always done under the house. They might try to sell you on open cell for the walls, in an old structure every bit helps so stay with closed cell. Is more expensive but well worth it. The next project is windows......

[masraum]

Originally Posted by Instrument 41

I have done 3 houses built before 1900. All of the same construction. One of the things we did when I hade it sprayed with Closed cell foam insulation from the bottom is not just in between the beams but also along the outer perimeter so that you don't have to stuff the voids with pink insulation. When you would look under the house it was completely covered on foam. The closed cell is almost always done under the house. They might try to sell you on open cell for the walls, in an old structure every bit helps so stay with closed cell. Is more expensive but well worth it. The next project is windows......

Right, I closed cell seems like the way to go as it should also protect from moisture and work as a better insulator.

We got fairly lucky with this house. It was built around 1920 by the first owners. The man died in 1960 and the wife in 1965. I spoke to a family that bought the place around 1990 and they said that it had been empty/derelict for a while when they bought it. I'm guessing it may have been the 25-30 years between. Anyway, they rewired with romex, plumbed with PVC, and installed central HVAC. So the various systems in the house are in pretty good shape (HVAC needs to be replaced as it's still dated 1991). I believe they replaced the windows, but I think someone else has since replaced them again. They are all vinyl framed double pane.

[cabmandone]

Pull out the batting, put the shiplap back on the bottom and blow the walls with fiberglass insulation. It's better than the cellulose paper stuff because the fiberglass doesn't settle.

[A930Rocket]

I would seal the gaps, but I don’t think foam in a can is what you want. I heard termites eat that, correct?

[masraum]

Originally Posted by A930Rocket

I would seal the gaps, but I don’t think foam in a can is what you want. I heard termites eat that, correct?

Interesting, I'd not heard that, but if it's the case, then hell no, that's not what I want!

[drcoastline]

In the red box at the floor an exterior photo would be heplful. That being said I would caulk that gap not use expanding foam. I would then use a piece of one by to close the cavity. In the yellow box I would remove the insulation and also seal off te opening. Pull a board in all cavities and rmove the insulation and close.

I would then drill a hole near the ceiling at each bay and blow in insulation to fill the cavity. Glue the plug back in the hole.

[Aurel]

Insulting a 100 year old? I would never do that.

[masraum]

Termites don't eat the foam, but they can apparently use the foam as a home and it made help them spread throughout the wood more easily. As this home is pretty much all wood, I don't want to help them in any way. I guess I'll use some caulk.

[mattdavis11]

It looks as if the framing is cedar. Mine is, and that's a good thing. Termites don't like that stuff.

Subscribing, our home has little to no insulation, pier and beam, 1950's. Even the piers are cedar stumps.

[drcoastline]

To ad to my post above, several issues with expanding foam in this application.

1. It is not UV stable so anything that makes it to the exterior will detriorate quickly.
2. The siding is likely thinner then the interior wood so will give first likely casuing bulges in the siding and possibly popping fasteners from the studs.
3. It will likely push it's way bewteen laps in th siding.

[ckelly78z]

Originally Posted by masraum

Interesting, interior walls too. OK.

.

It makes a much more private space if you can't hear what's going on inside from a different room.

It also provides more heat retention when in the shower, or shivering on the toilet.

[john70t]

I would not spray in enclosed spaces without ventilation for a week.
That stuff will make ya sick.
Even outside with a chem mask, I still got a bit sick.

[john70t]

Originally Posted by drcoastline

2. The siding is likely thinner then the interior wood so will give first likely casuing bulges in the siding and possibly popping fasteners from the studs.
3. It will likely push it's way bewteen laps in th siding.

One technique is to spray the first layer further away and faster.
It goes on like a dust coating because the chemicals mix in the air.

Second coat is closer and slower and fully expands on the surface.

[masraum]

Originally Posted by drcoastline

In the red box at the floor an exterior photo would be helpful.

I don't have a pic of that exact spot, but this is what it looks like. The gap in the previous photo would be just above the red line in the photo below.



Most of the house is wood plank siding that is tapered. In the diagram below, it's what is labeled "sawn weatherboard." At the very bottom of the wall, there's a small piece that is, I believe the thick end tucked up under the last board so that anything that runs down will float out away from the house.

That being said I would caulk that gap not use expanding foam. I would then use a piece of one by to close the cavity. In the yellow box I would remove the insulation and also seal off te opening. Pull a board in all cavities and rmove the insulation and close.

I would then drill a hole near the ceiling at each bay and blow in insulation to fill the cavity. Glue the plug back in the hole.

The bottom (10-12" can't remember exactly) will be covered with wood before we put drywall back up. The problem with the blown in insulation is that if/when we have to replace some siding, all of that insulation will come pouring out. The wall is shiplap - studs - sawn weatherboard siding. So, just like if we had to pull some shiplap off, all of the insulation would end up pouring into the room out of the wall, if (and we will) we have to pull/repair/replace any of the siding outside, that will open the cavity. That's why I'm going with fiberglass bats. If we have to pull/repair anything, they'll stay in place. They are probably more expensive and more trouble to install, but they are a better solution in the end.

Originally Posted by Aurel

Insulting a 100 year old? I would never do that.

You don't want a 100 year old house to be insulated?

Or are you talking about spray foam insulation is what you wouldn't do?

I'm just talking about a single thin bead of foam to seal the visible gaps at the bottom of the wall. I'm not talking about gluing the entire house together. I just want to seal the gaps and then use regular fiberglass insulation to help the house be more comfortable and energy efficient.

[masraum]

Originally Posted by mattdavis11

It looks as if the framing is cedar. Mine is, and that's a good thing. Termites don't like that stuff.

Subscribing, our home has little to no insulation, pier and beam, 1950's. Even the piers are cedar stumps.

I spoke to the folks that owned our home in the 90s. They said that the old piers were cedar stumps. Everything underneath now is modern, concrete, etc...