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7 Answers

Basement finish - existing exterior R-5 - questions on interior insulation

I am finishing my basement in Minnesota. It is a walkout design. The walkout portion of the wall is a 2x6 wall with typical fiberglass bats and poly on the interior. All rim joists have 2" of foam spray.

My exterior concrete walls are covered with R-5 foam board protected with a thin layer of sand/rock pebbles.

I have been told and read so many ways to finish my interior insulation that I am dizzy. I have been told:
- No insulation, R-5 on exterior good enough.
- Put poly on concrete and get R-15 Kraft faced insulation between studs
- No poly at all, R-15 between studs

Asked By ZDude | Feb 28 17
1 Answer

Vented Attic Vapor Retarder

Getting confused in my research today, looking for feedback.

Climate Zone 5, Vented Attic with Blown-In Fiberglass.

Is it correct, vapor retarders are not required in climate zones other than climate zones 6 or higher for vented attic assemblies?

Asked By Birdie L | Feb 28 17
4 Answers

Pink sill foam vs. green treated lumber

On interior walls sitting on a concrete slab. Which would be better? Green treated lumber or standard lumber sitting on top of the pink foam sill sealer membrane?

The treated lumber has borate/chemicals in it while the foam sill sealer doesn't put off VOCs.

Which works better, is longer lasting and healthier?

Asked By Peter L | Feb 22 17
8 Answers

New home build in Iowa (Climate Zone 5)

Is it possible for a new home build in Iowa, climate zone 5, to not have under slab insulation? What's the min code requirement for a poured concrete basement with walkout basement?

Is it normal to also have external foundation just sprayed with waterproof membrane and tiles?


Asked By user-6759891 | Feb 20 17
4 Answers

How to vent a crawl space — "Musings" article of May 13, 2011

I'm going to take the advise in the "Building an Unvented Crawl Space" by Martin Holiday that was posted on May 13, 2011.

It suggests putting a floor register in so air can move between conditioned space and the crawl space. It is then recommended that an exhaust fan to meet code requirements for conditioning the crawl space.

Is this fan exhausting to the outside? Or is it exhausting into the conditioned space. I think it is the latter but want to make sure. It is an 800 sf space 4' high with volume of 3200 cubic feet, What cfm fan do I need? Where is best place to put floor registers?

Asked By Walter Gayeski | Feb 3 17
5 Answers

Designing wiring with SIPs and keeping building tight

I am in the process of designing a Timber Frame to be enclosed by SIPs. I have a solid design for my plumbing fully enclosed within an internal service cavity and I am now turning my attention to the electrical. I always thought the electrical would be a bit easier to wrangle but I am stuck… My goal is to avoid hacking up the SIPs because I want to keep the building envelope as tight as possible to keep my heat load down. It also seems counterintuitive to me to spend all the money on SIPs and then cut them up. From what I understand these are the basic design approaches:

Asked By John Brown | Feb 1 17
3 Answers

Leaving rockwool exposed in basement ceiling

Hi. A few places in my basement ceiling cannot be finished with sheetrock: above the electrical panel, the concrete block wall behind the boiler, etc, due to too many pipes or electrical conduits converging. Yet I still need to maintain a fire-rated ceiling in those locations. The building inspector suggested I pack those locations with rock wool.

How can I do this and not have an eternal sprinkle of rockwool fibers raining down on me under these locations? Just curious what other people have done.

Asked By Theodore Theodore | Jan 24 17
2 Answers

Are polyisocyanurate materials considered vapor barriers and to be avoided for insulating basements?

I live in Central Minnesota. Our home was newly built roughly 3 years ago. It was not insulated on the exterior, but foil-faced DOW Thermax Sheathing was installed on the entire basement interior. This has a permeability rating of 0.03. This is basically an impermeable material. If we want to avoid moisture problems when finishing our basement, do we need to take this down and put up something with more permeability like EPS? We do try keep the humidity below 50 or 55 degrees in the basement.

Asked By Andrea Zimpelmann | Jan 15 17
7 Answers

Need 2 foot square of vapor barrier

I'm planning to take out the 50s era milk chute in our house tomorrow. This will leave me with a whole between 12-20 inches square. I'll put plywood of the same thickness and vinyl siding.

I'm fine on the vinyl siding and sheathing, plus a piece of fiberglass and then drywall. For all I have pieces of leftovers or can buy in small quantities.

I'm stuck on what goes between vinyl and sheathing. I don't want to buy a huge roll of tyvek for such a small area. I need this for tomorrow, day after at the latest.

Ideas? Suggestions? Thanks!

Asked By Jeremy M | Jan 20 17
2 Answers

Continuous back-up?

I am trying to understand the fire code here:

I want to put up some hardboard to cover ridig foam in my basement walls. What does the code mean by "3 mm thickness over continuous back-up?"

9.29.7. Hardboard Finish Material Standard

1) Hardboard shall conform to CAN/CGSB11.3-M, Hardboard. Thickness

1) Hardboard shall be not less than

a) 3 mm thick when applied over continuous back-up,
b) 6 mm thick when applied over supports spaced not more than 400 mm o.c., and

Asked By Marc Delisle | Jan 12 17
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