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8 Answers

I have built a home in lower New Hampshire, about an hour north of Concord, using a hybrid insulation system.

The Insulating Contractor recommended 2" and 4" of closed-cell foam in the walls & ceiling respectively with the rest of the cavity filled with fiberglass batts. I defered to his "expertise" and had the system installed. After the blueboard was hung, the skimcoat of plaster applied, and allowed to dry I noticed some wet spots on the floor and lower walls that eventually dried. After checking the surface of the plaster with a moisture meter (reading was5%) and the relative humidity in the home was a very dry 35% (indoor temp.

Asked By Rick | Jan 10 10
11 Answers

Double coil air-handler / dehumidifier?

I’ve been giving a lot of thought to Joe Lstiburek’s most recent post over at Building ( and I’m especially struck by the illustration #6 showing a hotel room with a freestanding de-humidifier sitting next to a PTAC through-wall heat pump.

Asked By Michael Chandler | Jan 2 10
7 Answers

How should I insulate my roof?

I am building a log house and am at the point of insulating my roof. It is a metal roof with 2x10 rafters. The guys I am hiring to insulate said I have a couple of options. Condensed fiberglass R-30 batts are out because they are special order and I can't get them for 2wks and the guys are coming next week. I could put 2x2 furring strips to create the 12" I need for air flow and do regular R-30. I could do spray foam. They said 1". and then do the regular R-30. This woul give me about R-37. Or I could do blown in fibergalss insulation.

Asked By Amy | Dec 31 09
9 Answers

When is a continuous self-adhered membrane required on a roof?

Typical roofing details call for one course of self-adhered membrane (aka fully-adhered membrane waterproofing, ice & water shield, etc.) at roof edges and valleys. A continuous cover of self-adhered membrane, however, is often used (see BSC's Figure 9, RR-0404: Roof Design for an example) over roofs with metal roofing and spray foam in the cavity. Under what conditions is a continuous cover of self-adhered membrane required / recommended ?
- all metal roofing over unvented assemblies?
- only in cold climates?
- only in very cold climates?

Asked By Stephanie Horowitz | Dec 8 09
6 Answers

Insulation behind Shower surround

I have heard multiple ways to best insulate behind fiberglass/tub surrounds below grade. We always insulate basement remodels with 2'' of XPS = R-10 against the foundation wall (sealed with canned foam all 4 sides, seams) and then frame out for the tub/shower surround.

Asked By Matt | Dec 4 09
8 Answers

How can I prevent interior condensation?

The condition is question is a coastal structure very close to the waters in the south Texas coastline. The structure dates from the seventies, a typical stud wall, siding and pre-finished plywood exterior wall system construction which never exhibited problems encountered after a current renovation. Three years ago, the siding was replced with vinyl siding because this was perceived to be more durable than wood siding. Insulation is believed to be sandwich along the woods studs and the interior plywood finish was replaced with painted wood bead-board panels.

Asked By Mike Silvestre | Nov 25 09
3 Answers

OSB Radiant sheathing & Tyvek housewrap exterior walls

I am looking at building a new house. I am going 2 x 6 exterior walls & blown cellous insulation. I am going to put the OSB radiant sheathing on the roof. My question is should I also put it on the exterior walls with the radiant side on the outside. I am also going to have the house wrapped with Tyvek. The house is going to be brick. I live in Dallas, TX where it gets hot.
Am I wasting my money on doing both and am I going to cause any moisture & vapor problems?

Asked By Debra Markwardt | Nov 24 09
2 Answers

Can I use GBA info in company newsletter?

It happens quite often that I read things in GBA and think, "My customers would appreciate knowing this". Can I use this info in a newsletter or are there copyright issues? Thanks

Asked By David Anderson | Oct 15 09
1 Answer

Has anyone had to retrofit a building with single wythe masonry walls?

I am working on a property in Detroit that has, as a wall system, a single wythe of 6 inch brick masonry with sheetrock installed on 1 5/8ths furring strips. So, as you might imagine, air and water runs through the building. Can we build a rain screen from the inside or clad the outside? Or gently push it in the river. I heard an architect say he had seen other buildings constructed this way so I was wondering if anyone had any sources for ideas on how to approach.

Thanks for any help.

Asked By julie klump | Nov 3 09
8 Answers

Installation of Vapor Barrier

Can anyone tell me how a vapor barrier is installed? I am a 63 yr old lady who purchased a doublewide put on a concrete foundation, and the crawl space if full of dirt. The man who contracted to prepare the foundation, said your put dirt on it to hold the plastic in place. Someone dug 14" and found no plastic. I paid $1500.00 for a vapor barrier that I'm sure I don't have.

Asked By Sydney Morgan | Oct 23 09
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