Hello:
Live in New England.
If I re-do my house with vinyl siding, which would go directly over the present T1-11 wood siding which is in poor shape, does it make sense to have installed styrofoam (or other) insulation between the T1-11 and the vinyl ?
a. Would the added insulation R value (no idea what it would be) justify the added installation cost ?
b. Does it make for a "better" or smoother job ?
c. Anything to be particularly aware of in work like this ?
Thanks, Bob
Most vinyl installers use a styrofoam fan-fold underlayment as a standard practice over sheathing. It might be usable over T1-11, since it is sheathing.
The R-values is not great, but you can specify thick stuff that conforms to the contour of the siding for more R-value.
Here is an idea of what I am talking about:
On 1/24/2005 1:07 PM US(ET), Robert11 took fingers to keys, and typed the following:
It's another level of heat and sound insulation, and offers some waterproofing. I had 3/8" foam, faced both sides with aluminum foil, installed under my vinyl siding.
I don't remember what the added cost was, but it was not another stage of construction. The installer tacked up the foam as he was installing the siding. I don't know what the R value of my foam was, but every bit counts up here in the NE.
Since vinyl siding is 'hung' rather than nailed solidly to the wall, smoother does not enter the picture.
When you get estimates, get them with and without the foam. If the contractor doesn't mention foam in his contract, ask him about it as if an afterthought. It may be only a few hundred $ difference. My foam was folded into a package that was about 2' x 3' and when it was unfolded it was about 6' or 8' wide by 3' high (three or four folded panels). It took about 10 seconds or less to tack up the 6' or 8' panel, except those that had to be cut.
Vapor barriers are better on the inside of the wall, but this rule seems to be broken very often these days. If I had a choice I at least would use perforated foam, to let some of the moisture out.
Paul
Go with the strofoam you can only go so thick as the siding will stick out beyond the windows frames .
The second go around on my install I had the strofoam installed day and night difference when the wind blows and rattles the siding.
My next install will be concrete siding.
Tom
I had vinyl siding put over the T1-11 siding. The installers put the foam insulation between the T1-11 and the vinyl siding. I don't know if it adds ay more R value. It is an enclosed carport the floor was raised and insulation in the wall and the vaulted ceiling. But it is the warmest room in the house in winter and coolest the rest of the year. That was 13 years ago.
My son installs vinyl siding and always uses the foam under the siding. But I live in Florida. Except for the last 2 days it never gets too cold. But does a great job for the AC.
Pat.
It depends on what foam board they use. White is R 3.5 inch , red-blue is 5.5 inch , Foil coated is R 7.2 inch . Get the foil coated R 7.2 inch
Patylargo, your son instals it ? A great bs endorsement
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