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10 Answers

Thoughts on adding rigid insulation over existing siding.

We have a historic house that is undergoing a deep energy retrofit with rigid insulation being applied to the outside and then strapping and new siding. The contractor has ripped off a few layers of asphalt siding and is now down to the original siding. He would like to keep it on and simply put the new rigid insulation over the siding. It seems this will create some nice air pockets which be good insulators, and be a cavity for drying if needed. Does anyone have experience doing this and any input on pros and cons versus taking that original siding off and going down to sheathing?

In Green building techniques | Asked By Phil Kaplan | Oct 19 11
1 Answer

Condensation on uninsulated ceiling

I have a ceiling above my root cellar which is below ground, attached to my basement via an external grade steel door, outside my homes thermal envelope, and passively ventilated with intake exhaust piping.

In GBA Pro help | Asked By Andrew Katz | Feb 11 18
8 Answers

Another flat roof question

We have several hundred sq. ft. of unvented flat EPDM roof above a single story addition. The rafters are 2x8. We recently cut access and found 2-3" of very old fiberglass batts in the rafter bays - a total roof insulation of R11. When the roof needs to be replaced in >10 years, we will install external foam sheathing.

In the interim, what is the best way to increase R value without creating a moisture problem? And if every approach has risks, what are they?

Thank you.

In General questions | Asked By Emerson | Feb 6 18
1 Answer

Understanding water heater specs

I have some questions about tank type water heaters:

How do you compare the sizing needed for a gas tank vs. electric heat pump type tank. I read (perhaps on this site?) that heat pump type tank water heaters have much slower recovery and thus, for the same hot water demand, a house would need a larger tank with the heat pump type.
1. Is there a chart to compare needed tank sizes between gas & heat pump type tanks, including how the recovery rates of a specific tank impact this?

In Energy efficiency and durability | Asked By C L | Feb 11 18
9 Answers

Relatively non-toxic concrete joint filler/sealing material that will last?

I have a failed cove joint in my below-grade level, and need to replace part of the fiber board joint material that exists between the slab and foundation wall. I need it to be a permanent type repair, as it will be difficult to get at the joint after my remodel, and I have radon present in my soil.

Does anyone know of a product that both works well (i.e may have a 20+ year life on concrete, remaining attached and flexible) and isn't highly toxic or classified as a carcinogen?

In Green products and materials | Asked By Rossn1 | Feb 8 18
10 Answers

House next to deep rock quarry: How can I tap water below 12-16" of ice for heat?

We have 50' deep water 50' behind our house.Water is very clean with 20' visibility at least-comes from limestone rock --no creeks or rivers--it is a hole in the water table. 8 acres. we have only 48" of earth above flat limestone shelf that is entire area around us. It was a Quarry for limestone way back. the water is at top of shelf--about 48" below the yard.

My minisplit is outside in 20 degree winter air while its 32 degree's or above a short distance away?

In Mechanicals | Asked By Scout159 | Feb 10 18
2 Answers

Too many wall insulation options?

Building a new home in Kansas City (DOE Zone 4A; mixed-humid {not too far from cold}). Summers are too hot and winters are too cold. Looking for the most cost effective and efficient method to insulate the exterior walls. Reading different books and forums, I'm having a hard time coming up with a comprehensive plan. My in initial thoughts were, starting from the inside:

2x6 studs, 24 OC. Uses less wood than 2x4 studs, 16 OC and reduces thermal bridging.

In Energy efficiency and durability | Asked By BIC2 | Feb 11 18
7 Answers

Minisplit temperature difference between floor and ceiling

We live outside Philadelphia and have had a very cold winter. We had a mini split uint installed in a newly expanded room and blocked the two forced air ducts from the old portion of the room. The floor temperature is vastly different than that coming out of the unit.
A few details. Home was built in 1954. Half of the room (old section) is over an inaccessible crawl space. I has a flat ceiling and a ceiling fan. It has one outside wall.

In General questions | Asked By Bob Whitemarsh | Feb 10 18
5 Answers

Cathedral roof, unvented, rigid foam

Hey GBA,

I've been reading several articles on the merits of Vented/Unvented cathedral ceilings. I'm about to build an energy efficient home in a mountainous zone 6 with lots of potential snow load. I'm trying to get R-30 on the walls and R-60 on the roof. Our climate is quite dry and I assume most of the vapor pressure will be from inside to outside in winter.

In Green building techniques | Asked By Steve Mackay | Feb 9 18
2 Answers

Air-sealing a Solatube on new construction

I am planning a house, with cathedral ceilings, and my client needs some daylight from the east. The only way to get it is with a skylight, on the east slope of a cathedral ceiling (or a dormer, but let's not go there).

We are planning a "pretty good" house with an air barrier at the ceiling (drywall or MemBrain). It seems like a solatube (or competitor) would be better than a full skylight. But I cannot figure out how to run the air seal (and no response from solatube . . . 0.

Does anyone have experience with tying a solatube into a ceiling air barrier?

In Green building techniques | Asked By Mark Harrison | Feb 10 18
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