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5 Answers

If I have a 5 1/2 in. square framing bay and the exact same 5 1/2 inch square batt, does it matter which way I install it?

Does fiberglass work directionally? Or does it matter?

In Energy efficiency and durability | Asked By rich graves | Sep 13 14
2 Answers

So. Calif. — Adding insulation to existing walls that have fiberglass batts

I have a solidly built building - wood frame stucco walls. Built in 1960, (I helped) with rolls of pink fiberglass in the walls and attic. It is no longer effective against the heat.
What can we do to add wall insulation. I have had the walls of other homes insulated with blown in cellulose with success, but there was no existing insulation in those situations. Will blown in work with the old fiberglass in the wall cavity?
Is there a better option?
Thank you.

In General questions | Asked By Kay Park | Sep 13 14
3 Answers

Insulating interior AND exterior basement walls OK?


In Energy efficiency and durability | Asked By Nikola Kolarich | Sep 12 14
4 Answers

Ventilation above foam on roof application?

Just looking for others' opinions. Zone 5. 200-year-old colonial. Skinning existing old board sheathing with 1/2" plywood. Ice and water whole thing as air barrier. Adding 3 inches polyiso, 2.75 inches EPS on top.

Was planning to vertically run 2x4 every 16 inches securing through everything with Trufast 9" screws. Then install 1/2 in. plywood as roof nailing deck.

Is it overkill to ventilate this in this manner? Is it still necessary to tape each layer of foam sheathing if I do have this ventilation in place?

Appreciate others thoughts.

In Energy efficiency and durability | Asked By terry grube | Sep 10 14
0 Answers

Beware the dual-hose portable AC / heat pump

For years I've wondered if a dual-hose portable heat pump/air conditioner could be a poor man's ductless minisplit heat pump. The advantage, as my logic went, was that I didn't have to drill any holes or charge any refrigerant.


I bought a 14kbtu portable heat pump (Edgestar AP14001HS Portable Air Conditioner) ($400-$700)

I did some primitive temperature and airflow measurements.

I was impressed by the overall quality and the 11.2 EER, but what I found was very disturbing.

In Mechanicals | Asked By Kevin Dickson, MSME | Sep 12 14
11 Answers

I need help choosing the correct minisplit and heat pump for my studio

I have two proposals to install a single unit mini-split with an outdoor condenser for my studio building. The building has a 24 x 32' foot print. The walls are 10' high, with a cathedral ceiling that is 16' high at the ridge. Walls are 2 x 6 (at least) with fiberglass batts. Roof rafters are 2 x10" (I think) with fiberglass batts between, and then either 1 or 2" rigid foam insulation skimming it (under the sheetrock). Building is tight. Floor also has fiberglass and rigid foam board between the 2 x 12" joists.

In Mechanicals | Asked By DANIEL GOTTSEGEN | Sep 10 14
30 Answers

When roofs do rot, which side does the rot start on? worth using copper-borate treatment as preventative?

When roofs do rot with closed cell foam underneath, which side does the rot start on?

Is it worth using a copper-borate treatment as preventative?

Zone 6. There will be 4" 2lb closed cell foam on the underside of the sheathing. tar-paper on top. Attic space will be living space. not expecting to have any rot issues but....I'm thinking a belt-suspenders approach here. considering spraying whichever side is prone to rot in this situation with a copper borate solution as a preventative.

thank you.

In General questions | Asked By eric Mikkelsen | Sep 8 14
2 Answers

Improved air sealing brings other challenges

In Kansas 9 Jurisdictions allow an Energy Rating Index analysis as an alternative compliance path for meeting the 2012 IRC chapter 11. Other builders use the HERS index for marketing purposes. Use of air sealing recommendations and increased quality of installation have seen air change rates move down from 5-6 ACH pre-implementation to 3 ACH or less in a growing number of audited homes. Early antidotal results are showing problems with supply only strategies. The 6" pipe to the return is causing summer humidity problems in some cases.

In GBA Pro help | Asked By Bruce Chyka | Sep 10 14
4 Answers

Necessary layers for a wood-framed insulated metal building

I have recently framed up my new wood shop. Initially, I was going to do cedar siding and metal roof, but now have decided to wrap the whole building in metal (black metal at that) for ease of install and durability...and black metal just looks darn good. The building is now covered in tyvek on sides (on 1/2" osb) and underlayment on the roof (on 5/8" plywood). Should I take down the tyvek (which was intended to go with wood siding) and use some other material before i put on the metal siding? Should i install horizontal batten strips to help the building "breath"?

In Energy efficiency and durability | Asked By Zane Morgan | Sep 11 14
3 Answers

Double insulated rim joist?

Is spray foam on the rim joist beneficial/necessary if there is already an inch of xps on the exterior of the sheathing? The plan is to use dense packed cellulose in the walls above and below. The framing is 2x6 and this is a doubled 2x10 rim joist. (Zone 4).

In General questions | Asked By mike mcguirk | Sep 11 14
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