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54 Answers

Another crawl space in the Northwest

Hello all, I have a 1150 sq ft rambler house in Fall City, Washington (near Seattle), zone marine 4c. I am currently in the process of redoing the crawl space. I have pulled the damaged and rodent infested insulation down, and removed the town vapor barrier. It seems I had some rodents that were digging past the foundation and getting into the crawlspace, ruining everything.

In Energy efficiency and durability | Asked By David Meyer | Nov 28 16
10 Answers

Foundation waterproofing retrofit

Howdy. I know questions come up like this all the time but I've been reading a thousand pages on the subject and would appreciate some sanity-checking on my plan.

We bought a house last year that's roughly two years old. I'm no expert, but I think it would be considered a mid-level build; it certainly isn't a green/leed-level design.

We have a poured concrete foundation with a crawlspace. Heavy clay backfill. I've noticed some water intrusion into the crawlspace around some of the pipe penetrations; not a ton of water, but some.

In General questions | Asked By Maurice A | May 13 17
2 Answers

Rheem heat pump water heater ducting

I'm in climate zone 4C, 22°F design temp, 4500 HDD, high radon potential (conditioned crawl not allowed). My heating season is basically mid-Nov through end of April. Cooling from mid-June to mid-September.
Energy Star is rewarding the use of an HPWH and the local utility is offering a $500 rebate for such (free money).
Does it make more sense to
1) Install the WH in the garage, which gives up the cooling in the summer and the COP in the winter (it will use more resistance heat in the winter);
2) Duct it to the attic or crawl space all the time;

In Energy efficiency and durability | Asked By Mark Walker | May 13 17
8 Answers

Would a rainscreen be required?


I would like to install 1.5" of mineral wool on the exterior before finishing with vinyl. I am pretty sure vinyl siding can be installed on foam insulation up to 2" without a rainscreen suggested but the mineral wool is less dense and I worry it wont hold the vinyl the same.
Are there any best practices when installing vinyl over mineral wool?
Thanks in advance

In General questions | Asked By Jeremy Archer | May 3 17
18 Answers

Is a single head minisplit practical?

This is a mostly accurate plan of dear, old Mom's house.
2265 ft²; zone 4 marine; target ACH50 = 1.5; 5000 HDD; 22°F design temp;
2x6 walls w/2 stud corners, 24" o.c., 1½" horizontal cross-hatched walls (similar to "Mooney"), 7" of dense pack cellulose; front wall faces north; awesome PV potential on south facing roof.

In Mechanicals | Asked By Mark Walker | Apr 27 17
2 Answers

Furnace cold air return requirement with HRV

New build in Ontario with Zehnder ComfoAir 550 HRV (home run system - not tied into furnace)

Does the furnace need traditional cold air returns in various rooms or can we just draw air back into the furnace directly from the basement (where the furnace is located)

The HRV is already moving air so not sure of the purpose of the cold air returns in this setup


In Building Code Questions | Asked By Steve Babcock | May 12 17
5 Answers

Bringing down the cost of PERSIST construction

I really like the idea of PERSIST houses. Keeping insulation on the exterior makes a lot of sense, and there are few more foolproof methods to build a strong air barrier. But the undeniable drawback to PERSIST construction is cost. Peel and stick membranes are significantly more expensive than standard housewrap, and there is a lot of OSB sheathing involved. REMOTE constructions address some of these concerns, though really only work with unconditioned attic spaces. I was trying to think of ways to bring down cost and reduce material use, and I had an idea I wanted feedback on.

In Green building techniques | Asked By Aedi | May 12 17
9 Answers

HVAC system for a tiny house

Hello all.

I have posted a few times in the GBA Q&A and have gotten some excellent advice for my tiny house on wheels. I have read a few other tiny house posts by others on here, but there are not many.

In Energy efficiency and durability | Asked By Grey Wolf | May 8 17
28 Answers

Sell me on rigid foam exterior in climate zone 3A

Starting building on our dream house in a few months. Plan to live in for 30+ years. House will have Zip Sytem sheathing and will be well insulated on the inside, I will just leave it at that. Not interested in installing rigid foam on outside of roof sheathing (I have my reasons, so please don't try to convince me otherwise).

So.... House fully exposed to sunlight. 1" rigid foam with foil face. Strapped with cement fiber siding.

Sell me on all the reasons why this is worth the time/cost.


In Energy efficiency and durability | Asked By Farm House | May 9 17
13 Answers

Retrofit single ductless minisplit to cool entire upstairs

Hello, I'm a huge fan of this website, but I finally joined so that I could ask this specific question:

My wife and I own a 2000 sq-ft colonial built in 1962 in the Metro Detroit area (climate zone 5), with only baseboard heating--no central air. The first floor can be kept comfortable with a single wall-mounted AC unit and some fans to help circulate, but the upstairs is a bigger challenge. We've had several options quoted to provide some form of AC, but we're leaning strongly towards a ductless minisplit system.

In Green products and materials | Asked By Nathan Efrusy | May 9 17
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