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Have any of you heard of a 3/8″ styrofoan house wrap instead of Tyvec ? I will be having my house re-sided using seamless steel siding and the contractor suggested using a 3/8″ styrofoam wrap (called amocore ?)instead of Tyvec. They offer both products. Is one better (in a Minnesota climate ) than the other ?
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John,
My recomendation would depend on certain things. Are your walls 2 x 4 or 2 x 6? How much insulation is in your walls? Is the old siding coming off? What type or profile is the new siding? Is the window & door trim being covered with something also, such as aluminum? Does your house seem drafty or pretty comfortable the way it is?
The 3/8" foam doesn't give you much in the way of R-value and the Tyvek is a much better air infiltration barrier. Without more information, I'd go with the Tyvek or a thicker foam.
*Red Dog, how is Tyvek a better air infiltration barrier than foam? I don't know all the performance characteristics, but I think foam would be at least as good at stopping wind from getting in, or am I missing something?
*Jason,The foam products come in sheet form, creating an awful lot of seams, ideal for air leakage. The Tyvek comes in up to 9' rolls and you are able to overlap it as much as you want. While you could tape the seams of the foam, that's a lot of tape and seams and then you're relying on the adhesion of a lot of tape over the years for the air barrier. Red dog
*Red Dog,I'm not too concerned about the insulating factor of this stuff, although if the cost is OK then any R value increase would be a plus. I'm more concerned with whether or not it will perform adequately as an air infiltration barrier. If either I or the contractor did tape all the seams, is the foam a more preferable base for steel siding than Tyvec would be ?My walls are 2 x 4 with R-13 insulation in the stud cavities. Additionally I have a 1" layer of R-5 Foamular on the inside of the walls, with 5/8" sheetrock applied.Yes the old siding is coming off, the windows and doors will all have steel cladding applied, and no, the house isn't drafty......since we did all of our remodeling. We took care of all of those problems already ! Thanks.
*Go with the Tyvek. I can't see the foam being a better base unless the sheathing on the house is pretty rough, then the foam might smooth out some of the irregularities. Just curious, I don't believe I've seen steel covered trim on a house, it's all aluminum around here. Will all this trim be made on the job or fabricated in a shop somewhere and transported to the job? Why steel and not aluminum; durability, colors, cost? Will the overhangs be covered also? Gutters?Red dog
*Red Dog,The contractor I will use for the steel siding will also form the cladding for the doors and windows. My assumption is that it will be steel, although it could very well be aluminum as you suggest.I know he will form the dutch lap on the site, and same for the cladding. I decided to go with steel for the siding because I didn't care for any of the vinyl I saw, and the aluminum just seemed to be easily dented.I am also having my soffits and fascia done at the same time.My sheathing is the good old Built-Rite, commonly called Buffalo board. It is NOT my first choice in sheating, but it's already there. My house was built in 1975.I have little knowledge of what is best for under the replacement siding. I have found a few web sites that really push the foam under the steel, and the contractor seemed to feel that would be the better option. Is this just a matter of profit margin, or is there a BEST answer ?