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4 Answers

Insulating a cathederal ceiling roof?

We have a home with a cathedral ceiling and fiberglass batt insulation. We are considering while we are replacing the roofing in installing spray foam insulation. The proposals are to apply 5 -6 inches of spray foam to the ceiling deck not the back of the roof deck as we would have to remove the drywall ceiling inside to apply the spray foam to the underside of the roof deck. Is this a viable/ effective application? What might be the problems or issues?

In General questions | Asked By mercierfamily | Mar 13 17
11 Answers

Heat-pump water heater for an all-electric garage apartment?

We our building a detached garage w/ 2nd story apartment (1 bedroom, ~900 sq ft conditioned space) & debating the system to heat water:
- Primary purpose for the garage apartment is for our mothers to live in as they age. Mainly for safety reasons, we're not having gas service to the apartment (could do relatively easily - main house has gas service)
- Cooling-dominated climate (Houston TX)

In Mechanicals | Asked By Robert Hallenbeck | Feb 9 17
8 Answers

Is 4.5 ACH50 too high?

Bought a new home, fairly new construction (2yrs old) 3400 sq ft. 2 levels. our area straddles zones 5b and 6b, so depends on the year, can be either pretty cold or mild winters. summers are always dry.

In Energy efficiency and durability | Asked By shammah98 | Mar 11 17
3 Answers

Finishing a basement wall that has previously been painted

I am in the process of framing up a basement that has previously been remodeled using panels that were directly glued to the solid poured foundation. As I am removing the wall covering, I am noticing that the concrete has been painted previously. My plan was to remove any adhesive, wash walls with a TSP substitute and allow area to dry. I was planning on using 1/2" EPS glued to the wall and place more EPS in the rim joists and using a fire retardant foam to seal in those areas. I was then going to leave a sight gap 1/2" at the bottom of each panel and seal all seams with tyvek tape.

In General questions | Asked By Michael Kendall | Mar 12 17
1 Answer

Vented and unvented roof combo

Is it possible to have a combination vented and unvented roof assembly? I own a house in southern Maine that has a vented roof. The house also has cathedral-style ceilings in two upstairs bathrooms, and it's the roof above these bathrooms where I've recently identified an ice dam. Because the bathrooms have skylights, where venting may by difficult, my thought was to constructed an unvented roof over those two rooms and leave the rest of the attic roof vented. I have no plans to convert this space to a livable area in the future so changing the who roof seems unnecessary.

In Building Code Questions | Asked By Todd Bridgeo | Mar 14 17
2 Answers

Retrofitting a conditioned attic where there is an attached garage (Phoenix, AZ)

A few years ago, we purchased a 20-year old, single story production home in Phoenix, AZ, where the both air handlers, induced combustion furnaces and ductwork are located in the attic. The ventilated roof is covered with low profile cement tiles and O-Hagin roof vents. We recently had an energy audit where the CFM50 = 2100 and estimated R-23 in the attic the auditor recommended more blown in insulation and upgrading our HVAC and ductwork. But we’d rather create a conditioned attic.

In GBA Pro help | Asked By Eve McFadden | Mar 14 17
6 Answers

Cathedral Ceiling Meets Hot Roof Twist (Winter 2 Update)

This past winter again found my wife and I again pondering the ceiling in our new home in North Central Minnesota. Condensation drips near where the wood burning stove chimney penetrates our great room cathedral ceiling. Drips occur while operating the wood-burning stove during double-digit sub-zero temps. We reached a low of - 31.

In Energy efficiency and durability | Asked By Randy Bunney | Mar 11 17
6 Answers

Airtight wall sheathing options

Having read on this site some questions about the airtightness of OSB, we asked our builder to price using Zip panels (uninsulated variety) instead of commodity OSB as our wall sheathing. Since we're using EPS foam exterior to the sheathing, and then housewrap, the water barrier aspect of Zip panels would essentially be wasted. But we'd be getting the air barrier.

Builder says this would increase costs by about $2500, so we're looking for alternatives, or thinking about just taking our chances with commodity OSB, since so many seem to have achieved high levels of airtightness using it.

In Energy efficiency and durability | Asked By William Costello | Mar 14 17
3 Answers

Tankless water heater - mount inside or outside?

I am in middle of a 6000 sq ft home build in Alabama. Will be using 2 tankless water heaters. I have space available to mount inside attic but could do outside. Appearance wise, it would be nice to be inside so don't see on outside of house.

Should I mount units inside or outside? Seems like being inside and not being exposed to the elements outside would be better. However, maintenance appears to involve annual or so flushing which would be a nuisance to haul the solution and equipment into attic.

In General questions | Asked By Richard Marks | Mar 13 17
8 Answers

How to duct a Whole House Dehumidifier?

I am building a 6000 sq ft house in Alabama. Downstairs is about 4000 of those sq ft. On one of the two A/C units downstairs, we are installing a whole house dehumidifier. My installer will install however I want but he typically pulls air from the return trunk, and returns into the supply trunk bypassing the air handler. Is this the best way to do it?

I've read some prefer to have a dedicated vent in the house to pull in air to WHD and then return to the supply trunk after the air hander. Thanks.

In Mechanicals | Asked By Richard Marks | Mar 13 17
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