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6 Answers

Insulating interior basement walls with rigid foam board

My house was built in the 40s. The basement walls are not smooth. There's approx. 6 horizontal lines from the basement floor to floor joists that stick out about 1/4inch. The rigid foam board will not be sitting perfectly flush on the wall, is this a problem?

The joists were set in the concrete. How do i insulate the space between the bottom of the joist and the top of the joist? With scraps of rigid foam or with spray foam?

In General questions | Asked By user-7114034 | Jul 11 18
17 Answers

Wall assembly help


I wanted to get some advice on two wall assemblies I am considering. I am in Iowa- climate zone 5. Cost is a factor but would like to have an efficient assembly as we are going to live in this house for a long time.

Option 1 from outside in
LP Smart side
1/2” furring strips/rain screen
1 1/2” XPs rigid foam
TyVek commercial D drain wrap
2x6 standard framing with BIBS and my insulation contractors basic air sealing package
1/2 Sheetrock latex paint

Option 2
LP smartside
Homeslicker drain mat
ZIP R sheathing 1.5” r vale 6.6
2x6 wall BIBs and air sealing

In Energy efficiency and durability | Asked By jrpritchard | Jul 10 18
5 Answers

Insulating stud bays: Spray closed-cell foam directly on 1x6 diagonal sheathing or use asphalt felt with air gap?

Hi All,

We're renovating a historic 1935 brick home. Once the interior paster was removed from the walls, we found 1x6 diagonal sheathing (in great shape). While the stud bays are open, we'd like to add insulation to the house.

The house is framed with 2x4 (1.75x3.75 actual) studs.

My original plan was to line the stud bays with asphalt felt, leaving 1/2 to 3/4 air gap to allow the stud bay to dry out, and seal it up with 1" of closed cell foam, and fill the rest of the bay out with open cell foam.

In Energy efficiency and durability | Asked By Getco | Jul 12 18
4 Answers

Fastener length for strapping

I finished installing a plywood ceiling air barrier directly onto the bottom of 24"oc trusses (ring shanked nailed) and I'm going to be installing 1x4 strapping at 16" oc to hang the drywall. What length of screw would be long enough to secure the strapping thru the plywood (1/2") and into the truss? I'll be installing 1/2" drywall. I'm thinking 3" screws but not certain.

What about the 3/4" gap the strapping creates, is it best to just leave that air gap empty between the plywood and the drywall? I don't really need the gap for wiring as the ceiling lights will be surface mount.

In General questions | Asked By Smokey059 | Jul 12 18
1 Answer

Intello and acoustic sealant?

Does anyone know if regular acoustic sealant (like PL Acousti-Seal) will work with Intello without damaging it or causing some sort of negative side effects? I'm finishing up my air sealing strategy which will include some Contega HF in the usual places, but I have a larger area to handle with acoustic sealant (for cost reasons) which will be in contact with the Intello.

I just want to be sure it won't hurt my premium vapor retarder.

In Green products and materials | Asked By Lance Peters | Jul 12 18
3 Answers

Insulating kneewall with no soffits

The articles I've read talk about air flow coming from the soffits. My house doesn't have soffits. The only air flow is from the roof vents. Do i insulate the roof and make the space conditioned space or insulate the knee wall and floor leaving the space as unconditioned?

In General questions | Asked By User-7114034 | Jul 11 18
1 Answer

Not a question, just an FYI

Solar pv rebates are finally coming to Canada!


In Green products and materials | Asked By Calum Wilde | Jul 12 18
5 Answers

Is sheathing necessary on a chimney chase?

I have framed a chimney chase of considerable height over my garage.

I was planning on nailing board and batten siding (1x12 Eastern White Pine with 3" battens) directly to the frame.

The structure is extremely stout, so I don't need sheathing for racking resistance; can you think of any compelling reason for me to add it?

The flashing will naturally run up behind the siding. Should I refrain from nailing through the flashing?

In General questions | Asked By Ben C. | Jul 12 18
2 Answers

Can you flash and batt with the spray foam on the inside?


In Energy efficiency and durability | Asked By Fallwanderer | Jul 11 18
2 Answers

Insulating interior basement walls if exterior has waterproof membrane and rigid board

The exterior basement walls have waterproof membrane and two inch foam board installed. To insulate the interior basement walls, can i use the old school method of studs, fibreglass and poly?

In General questions | Asked By user-7114034 | Jul 11 18
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