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6 Answers

Horizontal roof strapping for ventilation?

I am building a 16'x24' house in Alaska, 12/12 gable roof using 2X12 rafters, with a cathedral ceiling. A friend has recommended venting the roof by strapping the rafters horizontally with 2x4's at 16" o.c., thereby allowing cross ventilation from gable to gable. The roof would be sheathed on top of the 2x4's. I haven't been able to find any information on this technique on the web.

Asked By Justin Smith | Jul 15 13
3 Answers

Roofing question: Do I NEED 5/8" plywood decking under a 50-year steel roof?


House 6:12 pitch, garage 3.5:12 pitch

Trusses 24" OC, 2X6 top cord (solar ready). Climate zone 6A, mid to low snow load.

Asked By Mai Tai | Jun 10 18
3 Answers

How crazy is my plan to circulate air in 350 sq. ft. of space with closed doors and no windows?

I'm working on a 650 sq ft office suite located in Los Angeles. The space is split roughly in half: two therapists offices (windowed) take up one half. A waiting room, hallway, bathroom and kitchenette (none windowed) take up the other half.

The therapists offices currently have in wall ACs that are too loud for therapy. We're looking at Ductless ACs as an alternative but the budget only allows for a Dual Zone system. The indoor units would have to go in the therapists office, there is really no alternative here.

Asked By TB93 | Jun 8 18
13 Answers

Using one minisplit head (wall unit) for two small rooms

Currently I have a ducted HVAC in my urban rowhouse condo (495 sq. ft total, living room is about 220 and bedroom 180), I have long wanted to install ductless A/C & heat to remove the large duct hanging from my living room and kitchen ceiling and give me an extra closet (worth about $100-$150 month to me). That old system finally died.

Installing ductless in the bedroom is not as easy as I thought - there is limited space above the ceiling &it's a historic facade; condensate will have to go through the entire wall of my apartment to the back.

Asked By haiku_r | Jun 6 18
3 Answers

Partial basement?

Lost our home to a fire in January. Finalizing plans for our forever home. Plan on ICF. Wife and I were flirting with idea of putting in a partial basement (full basements are very rare around here). I was talking to one of the icf reps and he told me I couldn't. It had to be a full basement or none. I ask him why and he said it had to do with the weight of the walls. I planned on putting the partial basement under the center of the home. I thought as long as the basement walls and the house walls both had their own foundations it would be ok but he said no. Is this correct?

Asked By Mcoxrn | Jun 4 18
8 Answers

Vapor barrier over/ under scribed sleepers on concrete slab

We have an out of level slab by over 1-1/2". We plan on gluing and screwing scribed sleepers to the concrete, applying a 6 mil poly vapor barrier over the sleepers and then screwing plywood to the sleepers and installing engineered flooring material. There is foam and a vapor barrier under the slab. My question is if I put another vapor barrier over the sleepers... will this trap moisture since there is one already under the slab?

Asked By marc rubin | Jun 1 18
1 Answer

How do we hire a green building advisor on an hourly basis?

Does greenbuildingadvisor maintain a directory of recommended consultants?

Asked By Joe Martin | May 24 18
7 Answers

32'x42' concrete slab, 4"-5" thick, on foam and stable sand base: Do I need saw cuts?

Just poured the garage and had it sealed with a cure and seal compound. Slab ended up 5" in places (nominal 4"). I sits on 1 inch of foam and Ampex radiant panels (3 inch foam equivalent total). It's a floating slab, with 2 inches of foam separating it from the frost walls. The whole thing is on 4' of compacted sand, that sat for a year before the pour. Slab is 32 Mpa concrete with microfiber, no steel reinforcement.

My question is, do I really need the saw cuts? I would be willing to deal with the odd crack. I figure it would be a lot easier to keep the floor clean without the saw cuts.

Asked By Mai Tai | May 17 18
3 Answers


I've just found beetles (see picture). I know the signs, little holes in the wood all over.
This is on a 1925 stucco home in the San Francisco Bay Area fog belt. The evidence was found on a open foundation vent that's not protected from weather (apparently never painted since 1925).

Similar beetle damage appears on a decades old stored wood pile on the other side of the house, which cannot be moved because of the owner.

Asked By Bryce Nesbitt | May 16 18
1 Answer

Effloresence on concrete ceiling

Hello. I have a client with a basement that has a concrete ceiling section about 10'x35'. There is a brick walkway above it and it has leaked into the basement cieling causing efflorescence and that drops all over what they have stored in the basement.
Though someone sprayed Moxie on the exterior surface of the bricks, client reports they still have leaks in basement cieling that cause lines of efflorescence, which, again, falls on their pocessions stored below.

Asked By RSBme | May 14 18
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