Helping my insulation contractor make the right decisions. :)
Good insulation contractors around here are hard to find. A lot of people are doing the work without understanding many of the techniques shared on this site and others. I talked to the person I am considering for my new house and I think I could use your help in educating him a little.:)
1) Radiant barrier in attic
He is touting the advantages of an RB in the attic space. However, since my attic will be vented, have no HVAC duct work, and will use foil faced roof sheathing, I see no need for an additional RB. I know that even the RB sheathing maybe questionable in my zone, If its only a few dollars more a sheet, I’ll probably do it, since it will tend to lower the temp of the attic space, which will result in a lower delta t during the summer.
2) Taping the wall sheathing
He wants to foam the OSB sheathing instead of taping it. I don’t think this is a good solution long term and want to “prime” the joints with contact cement followed by 3M 8067 tape with a j-roller. This will be followed by a HydroGap WRB,1/2″ foil-faced polyiso with taped seams that are offset to the sheathing, a rain gap, and then the exterior finish (brick, stone veneer or engineered siding).
3) Crawlspace insulation
He is proposing a 12 mil liner and 2″ of EPS held by plastic anchors to the concrete/CMU. I am wondering if the anchors are adequate long term or should some foam board adhesive be added to make sure.
4) Air sealing<.b>
He proposes caulking and foaming. I am leaning toward Knauf Ecoseal Plus, which should penetrate the gaps more deeply and provide an extra layer of protection long term. I am fine with foam on the larger gaps.
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