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12 Answers

Bleaching mold on sheathing?

I'm building our house in Wisconsin, where we had a very wet June with 10 inches of rain while framing. The interior side of our 1/2" plywood sheathing has dried but has developed spots of mold. I'm considering misting it with a bleach mixture and letting dry well before insulating, rocking etc. The finished wall system will dry to the exterior, with 3" of Roxul Comfortboard IS on the exterior and Roxul comfort batts in stud cavities.

Any opinions on whether this is necessary? If yes, how strong should my bleach solution be?

Asked By Edward Krause | Oct 4 14
33 Answers

Why is there condensation on the return ducts and mold in the attic as well 60% humidity throughout the home?

This home has since been remodeled, including all new metal duct work and insulation. The issue that we need to resolve is the high humidity in the house at about 60-65% even though the unit is running efficiently. There is quite a bit of condensation on the return ducts in the attic as well. We have had two reputable Heating and Cooling Contractors come to assess the situation to no avail. The owner attempted to contact the original Mechanical contractor, but has not been able to speak to anyone yet.

Asked By Jimmy Miller | Sep 1 15
10 Answers

Exterior siding layers?

Hello all, I have a quick siding question.

When we spray foamed my shop with close cell spray foam we sprayed against the tyvek(housewrap). It was only one layer. It seemed like the best option we had at the time as I knew I would down the road drop the T-111 osb finished siding and replace it with plywood siding and housewrap and then a cement overlay (making faux stone work out of the cement)

Asked By Max Anthony | Sep 27 15
12 Answers

Thermal Break In Stud Walls


Just found this site 2 months into a renovation of one part of our 45 year old home. We have taken the main floor of the house back to stud/rafters and are now at the insulation stage. The original plan was Roxul with a vapour barrier in the walls with blown in ceiling, but we decided to go with 2lb closed cell foam in the walls to try and close the gaps and make the space more airtight and comfortable.

Asked By Richard Heatley | Sep 30 15
1 Answer

insulation type, etc.

hi all,

i have a semi-detached brick 2-family home in brooklyn. 20' x 65'. tenants are on the top floor and we occupy the first 2 floors. our ground floor is about 3 feet in ground on 3 sides and at grade in the rear. we are renovating and intend to put 2 full bathrooms and 3 bedrooms there, in addition to the laundry and utility room. we recently install a navian ncb240 which currently serves our dhw and baseboard radiators for both floors (tenants have separate boiler).

Asked By josh millis | Oct 1 15
1 Answer

polyiso along ceiling under truss chords

New build in climate zone 5. My plan is to establish my air barrier on the outside with zip sheathing and liquid flashing, and want to continue the air barrier across my ceiling (below a vented attic with blown cellulose). I thought about continuing the zip panels across the ceiling attached under the truss chords and tape them from the inside. I want to have options for drywall and tongue and groove wood for different rooms. I also thought about running polyiso boards in the same manner, maybe in two layers with staggered and taped seams. Any thoughts on this option?

Asked By Brian W | Oct 1 15
3 Answers

crawlspace foundation with wing insulation as well as vertical exterior insulation?

Hi. In northern New York state, climate zone 6. Preparing to build a 20 x 30 second home for a client that will be insulated but not heated for the foreseeable future. Some day it might be used year round.

Crawlspace foundation with footings to frost depth. We are planning to insulate the stem walls on the exterior with 2" XPS. A slab is planned at level of footing. We are contemplating skipping the sub-slab insulation of 2" XPS and adding wing horizontal wing insulation instead--in addition to the vertical stem wall insulation.

Asked By Jon Brown | Oct 1 15
1 Answer

Sub-slab condensate drain

This article mentions running a condensate drain for a mini-split to a leaching system under the slab, or tying it to the radon pipes. Is this a common/recommended technique? If tying to a DWV system risks leaking sewer gas through a dry trap, doesn't this system have the same risk for radon?


Asked By John Ranson | Sep 30 15
2 Answers

Insulating a pole barn

Hi. I am interested in building a small (20'x20') eco friendly pole building as a "tiny house". I like the idea of a pole building because it avoids the use of concrete for the foundation. I plan on using perlite bags beneath an earthen floor as the "sub-slab" insulation. For the walls and ceilings, I would like to use cellulose. I have not been able to find any details online for appropriately insulating and air sealing pole buildings. What resources I have found generally ignore thermal bridging entirely, for instance.

I would like to achieve R-40 walls and an R-60 roof.

Asked By Steven Gubkin | Sep 30 15
0 Answers

If you install a Dedicated Recirculation Line, can you have it run on demand? Or does it have to run continuously?


I'm trying to figure out the benefits/drawbacks of installing a Dedicated Recirculation Line versus an Demand- Initiated Recirculating System. I've already read Martin Holladay's great article in Fine Home Building.

Clearly, the demand-initiated systems are better suited for retrofits since they use the existing cold water line (at least the D'mand one I'm familiar with). And the Dedicated Recirculation Line is better for new construction due to the cost of installing additional plumbing back to the water heater.

Asked By Whitney Larsen | Sep 30 15
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