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monzamadman 06-10-2013 12:20 PM

Insulating from the outside
Hi everybody, I am wondering what,how I should go about this. I will be tearing off the old siding,and the boards under it and replacing it, I want to insulate the walls while I have everything off. What type of insulation should I use? What about vapor barrier?

nealtw 06-10-2013 01:41 PM

WElcome the site. Depending on where you live, some zones want the vapour barrier on the inside some on the outside and some don't use any. I hope you planning on doing this a piece at a time the sheeting is structual.

monzamadman 06-11-2013 03:46 AM

We live in minnesota,i am planning on doing a section at a time.As for insulation should i use faced or unfaced?If it is supposed to be on the inside shouldn't it be between the sheetrock and the studs?

WindowsonWashington 06-11-2013 05:36 AM

In theory, your vapor retarder levels should be to the warm side.

In your application, you would want it to be unfaced in a perfect application but if you get enough R-Value to the exterior, it is less imperative.

What is the wall construction?

Plan on spending some money on spray foam and getting it done right. If you take your time, you can detail and build a really fantastic wall system.

Vapor Retarder Levels

nealtw 06-11-2013 09:39 AM

There are a few ways to go, doing it wrong is as bad as not doing it. The idea is to stop air flow from inside from getting into the wall. Paper faced would go against the interior but there is no way to seal all the gaps. So if that's what you use you would have to seal all swtch and outlet boxes to stop airflow and then paint inside with a retarder paint. I would use poly 6 mill and wrap the stud and tuck it into the gavities. tape the joints and seal it to top and bottom plate with acoustic sealer and use batts. In a wet zone some gaps want to be left in the sheeting so moisture can escape to the outside, every bay.

monzamadman 06-11-2013 01:05 PM

As far as I can tell the walls a regular 2x4 framed walls,I was told it could be balloon construction, don't know if that would make a difference. Unfortunately I have to do this myself to keep costs down,but it still needs to be right so I don't have any issues later. What I need is the best way to do it this way,as the siding and the boards under need replacing. This is why I am doing it this way.

WindowsonWashington 06-11-2013 04:17 PM

Balloon framing does make for some more leakage but if you are stripping the walls on the exterior, you can cut and install blockers between the floors. This should be done from a fire standpoint anyway.

Get some putty pads to go around all the outlets and penetrations in the walls.

Check with code or engineer as to what the requirement is for either let in bracing or plywood sheathing.

monzamadman 06-11-2013 04:46 PM

Thanks for the info, I will check what code is,and figure out if it is balloon framed.

bud16415 06-12-2013 05:29 AM

With your location and talking about balloon framing and the type of siding and sheathing you have it sounds like you have a century old structure. I have seen them with sheathing on the outside then siding and lath and plaster on the inside. I have also seen them with the sheathing on the inside then the lath and just clapboard siding on the outside. The third method is what I have found in the house I’m renovating now and that is sheathing on both the inside and outside (1” rough saw) lath and plaster on the inside and clapboards on the outside. In my case there is also hard siding circa 1950 over that and then foam and vinyl siding over that circa 2000.

My concern in your situation is all that material really gone bad and needing replaced. You are really talking about a big job and chances are the original sheathing is still solid. In my case the sheathing is hemlock by the looks of it and it has darkened over the 100 plus years it’s been up there but is still 100% tough as nails. Without photos and until you open it up you won’t know for sure and is only a guess on my part. Quite often the lower one or two boards around overgrown landscaping might have rot and the south side the sun takes a toll on the clapboards. As Neal mentioned in these old places that sheathing was somewhat structural and many times run on the diagonal. They had it on there when they put the windows in and stuff is nailed to everything. Prying all that off may also cause problems with the interior walls if lath and plaster as you will be twisting the studs around getting the sheathing off.

I’m no insulating expert but I wouldn’t rule out just removing the old siding replacing any bad sheathing and boring holes and adding blown in insulation from the outside and then whatever the pros would recommend as wrap and foam then new siding.

Just a thought and you may have already figured out you need it all gone.

WindowsonWashington 06-12-2013 06:37 AM

Being able to get to the backside of the interior wall (plaster and lath or drywall) is a great benefit but will require the additional expense of pulling the sheathing.

If you are going for high performance envelope, that is what you are going to have to do.

Dense packing the walls, while not requiring the tear down of the sheathing, is going to be near impossible if you don't know what is in the walls or if it is balloon framed.

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