Insulation in an unsheathed wall?

[HerHusband]

We are remodeling the kitchen at my in-laws house and just getting ready to insulate. The house is about 100 years old, and does not have any sheathing, just siding boards nailed directly to the studs (diagonal braces built into wall).

After 100 years, many gaps have opened up between the boards, and there are signs that water has gotten behind the siding. Before we fill the bays with insulation, I want to minimize the chances of water getting in.

I caulked the larger gaps (from the inside. We already painted the outside last summer), in hopes of preventing rain from blowing in, but I'm concerned the caulking could fail in the future.

I have a roll of 15 pound roofing felt, and was thinking of cutting strips and stapling those into the stud bays before we insulate. I know felt was used under siding for many years before house wraps became common, and is still used in many areas. I realize it wouldn't be as efficient as a complete wrap of the wall, but I'm mostly just wanting to minimize the amount of rain that enters the wall.

Other than the labor of cutting the felt to fit around all the braces and blocking, does this sound like a safe idea? I don't want to cause new problems trying to solve other issues.

Thanks,

Anthony

[Steve Barker]

Just call the boys who do closed cell foam insulation and have them spray away. It'll stiffen up your structure also.

[willshak]

HerHusband wrote the following:

From what you describe, I would think that expanding foam insulation would be better. Not only would it insulate, but it would seal the cracks.

[v8z]

I'll third the spray-in expanding foam. It is available in DIY kits (google is your friend) if you want to do the labor. Just be sure to use appropriate safety gear.

[HerHusband]

Unfortunately, we already have the fiberglass batts and will be installing them tomorrow. Too late for spray foam.

Anthony

[willshak]

HerHusband wrote the following:

Well, there's always next time.

[DD_BobK]

Where is the home located? Vapor barrier & building envelop are issues that should have been considered. The suggestions of spray foam were good ones. Strips of building paper in the stud bays are a far cry from a complete wrap. :(

trying to solve other issues.

[Steve Barker]

LOL! if you're using fiberglass then why are you worried about some air leaks and what not? Never too late to do it right. You should at least put in wet sprayed cellulose.

[HerHusband]

Washington state.

If this was new construction, I would agree. However, this house is at least 100 years old. The siding was prepped and painted last year before we started remodeling the kitchen. Pulling the siding to install proper sheathing and building wrap is not an option now.

Agreed. Short of spraying foam insulation (which is not an option now), there isn't much I can do to completely wrap the space.

I was thinking of the felt as more of a splash shield and/or wind break than anything.

Me too. That's why I was asking for opinions here.

As I see it, I have three options:

1. Spray foam. Probably best, but not an option at this point.
2. Staple felt paper to the back of the siding. Reduce (not eliminate) wind and rain penetration.
3. Do nothing. Just install the batts in the stud bays and hope for the best.

While minimal, some moisture is likely to find it's way through the cracks whether I use the felt paper or not. Considering what I have to work with, it may just be best to do nothing. The house has survived 100 years that way, I see no reason it couldn't go another 20+ years.

Besides, I'm sure the rest of the house has the same gaps between siding boards too.

Thanks,

Anthony

[DD_BobK]

Anthony-

West coast or eastern desert? If you're in a dry area & keep indoor humidity low you might be fine.

But by adding the insulation & the strips of building paper you are changing the basic nature of a structure that has lasted 100 years.

I can't be sure but your current set of choices might be do more harm than good. :(

Insulation without a vapor barrier might encourage condensation within the wall, thus wetting the insulation and setting up the conditions for rot.

Vamos a ver.

cheers Bob

[Rico dJour]

I agree with everything you wrote except the use of the word 'might'.

Putting insulation in a house with compromised siding is not asking, but screaming for trouble. The house is 100 years old precisely because there is no insulation. Uninsulated houses dry to the inside as well as to the outside. Insulation will prevent the wood from drying out. Your tar paper diapers will simply prevent most water from soaking the insulation, but it will also mean the wet studs will have much less surface area exposed to allow drying.

You can't waterproof things that rot from the inside and continue to let water permeate in from the outside. It will just accelerate the rot. Spray foam would be a step up from the current plan, but it would create problems of its own.

You have tough situation on your hands. It is very difficult to stand by and not do something, but when the doing something causes more harm than not, well....

R

[HerHusband]

Rico,

Yeah, I always try to do things the right way, but this seems to be a situation without a good solution.

I have to insulate by code, but will skip the felt liner idea. Hopefully the walls will still breathe enough to dry out any moisture that does find it's way into the wall.

It's not like the house is a historic piece of architecture anyway. It was in very poor condition with lots of rot, peeling paint, cut away beams, etc. till we started fixing it up several years ago. Every little bit helps, I guess.

Thanks for your input everyone!

Anthony

[jloomis]

Go over the exterior siding with new siding. Use paper (30# felt) on top of the old siding. In the meantime finish the kitchen and caulk, tar paper anything to keep the rain out and the moisture at bay and when time permits reside over the old. Remember the old siding has more than likely lead paint on it also. jloomisconstruction.com

We are remodeling the kitchen at my in-laws house and just getting ready to insulate. The house is about 100 years old, and does not have any sheathing, just siding boards nailed directly to the studs (diagonal braces built into wall).

After 100 years, many gaps have opened up between the boards, and there are signs that water has gotten behind the siding. Before we fill the bays with insulation, I want to minimize the chances of water getting in.

I caulked the larger gaps (from the inside. We already painted the outside last summer), in hopes of preventing rain from blowing in, but I'm concerned the caulking could fail in the future.

I have a roll of 15 pound roofing felt, and was thinking of cutting strips and stapling those into the stud bays before we insulate. I know felt was used under siding for many years before house wraps became common, and is still used in many areas. I realize it wouldn't be as efficient as a complete wrap of the wall, but I'm mostly just wanting to minimize the amount of rain that enters the wall.

Other than the labor of cutting the felt to fit around all the braces and blocking, does this sound like a safe idea? I don't want to cause new problems trying to solve other issues.

Thanks,

Anthony

[bilb2765]

What if you paint, seal the interior bottom plate, and the lower foot or so of each stud. Then use the building wrap on the inside, wrapping each stud to give you the continuous barrier. Then insulate, and drywall?

My 2cents.

[HerHusband]

Probably not going to happen, at least in my lifetime. For one, we just prepped and painted the exterior last year, so we won't be touching the outside for some time (it will probably outlast my in-laws).

I caulked the larger gaps earlier, which should keep the majority of the wind and rain out. I also applied some expanding foam insulation yesterday to areas that looked like they could have issues in the future.

We skipped the felt liner, and just installed the fiberglass batts.

Anthony

[bilb2765]

Do the best you can. HerHusband might just become 'that Son-in-law'