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7 Answers

Deep blown in cellulose for attic - questions

I have a few questions regarding deep (beyond R60) blown in cellulose for an attic. Cellulose is relatively cheap and I'd like to maximise my attic insulation without causing any other issues:

1. Several manufacturers of cellulose insulation have depth/R-value charts that stop at R60. Is there any practical reason for this, or is it just because most people don't bother going above R60?

2. Does compression above a certain depth negatively affect the performance of the insulation in any way? I.E. does your R-value/$ go down appreciably beyond a certain depth?

Asked By Lance Peters | Apr 24 17
16 Answers

All-electric vs. natural gas in Zone 2

I'm building a house in Houston, Texas. It will probably be a 'pretty good' house - dense pack cellulose and exterior rigid foam installation with an encapsulated attic and targeting an ACH50 of <3 with an ERV system for ventilation. I will have a sizeable solar PV array on the roof - 6-8 kw so I have been debating whether to use natural gas as in my current house for multiple appliances or go all electric. Pros and Cons as I see them are:

Benefits all electric:
No standing monthly charge of $25 for gas since consumption is below threshold 9 months of year

Asked By user-6822325 | Apr 22 17
15 Answers

Raycore - is it the product for me?

I was pretty much on board with buying Raycore for the 4500 s.f. home I am building in downstate NY, which is steel framed, so I actually don't need any structural value out of the exterior walls other than for supporting the windows and doors (and supporting the walls themselves). I am also going with a wire lathe and stucco on the exterior - Raycore told me I could direct apply the wire lathe and did not have to use any sheathing if I did not need the shear strength, but I am hesitant to do so.

Asked By Joe McCarthy | Jul 14 14
1 Answer

Can rigid foam insulation be used on brick and mortar walls?

Hello, I am looking to finish my basement. I live in Chicago. 2/3 of the wall is poured concrete foundation. The top 1/ 3( which is mostly above grade) is brick and mortar. The brick and mortar section is also recessed from the face of the poured foundation by about 2in. I was orginally thinking of using ridgid foam but now after research I feel unsure about which type would best in my application. Any help would be greatly appreciated. Thank you , Steve

Asked By sburban | Apr 25 17
1 Answer

Should I place a vapor barrier on an inside wall?

I have built a wine room and have been advised that I should create a vapor barrier on the walls outside the wine room since I do not want water vapor to seep through the walls when the cooling is running. Is that correct.advisable? I live in New Mexico and have had a smaller wine room for eight years with no discernible problems and am wondering if I should do that. Also, I have been advised to place a vapor barrier on the outside stucco walls as well. Any comments and advice would be welcomed

Asked By Sabawa | Apr 26 17
6 Answers

Hip roof in Zone 6A

My client is a builder who has already completed the exterior siding and roofing of a new house in coastal Maine (zone 6A). The hipped roof and 2x6 walls have no exterior rigid insulation and no air space between cedar shingles and Typar. Walls: 2x6 with R-21 batt (John Mansfield), 1/2" CDX, Typar, cedar shingles. He plans to install shiplap hemlock paneling to the interior. Roof: Hip, 6 in 12 pitch, 2x10 rafters into (2) 11 7/8" hip rafters. Also has two dormers.

Assuming we go with an unvented assembly, how do we best achieve a vapor seal?

Asked By user-6825743 | Apr 22 17
22 Answers

Need sizing advice on a minisplit unit

I installed a Mitsubishi FH12NA in summer of 2014 when they first came out. I live in inland San Diego, and it can get hot, like 10-15 degrees hotter than the coast.

My condo is a studio and is only 420 sq ft. I'm on the upper unit of 2 stories. I face East and South. I have a skylight and dual-pane windows. Building is 1978 construction.

My Mitsubishi is weak. I set the temp and it will barely do anything. I have to set the temp to 61 and manually put the fan on high for it to do anything. Even "powerful" mode is weak.

Asked By aypues | Mar 16 17
4 Answers

Housewrap under rigid foam AND taped rigid foam at windows

the set up: Climate Zone 3. I'm using a standard house wrap between the OSB sheathing and the 1" rigid foam. The rigid foam will have all seams taped and will act as the primary WRB behind 3/4" vertical furring and lap siding. The Question : How do I terminate the house wrap at windows? just bring all the way into the "outtie" window bucks (caulk to buck), install rigid foam, then install window peel and stick flashing on bottom/part way up the sides. Install window. Would you recommend a 2nd layer of house wrap around the windows? Attached to the rigid foam?

Asked By Inger Peters | Apr 17 17
1 Answer

Insulating a corrugated metal floor deck

Hi -

I have a garage on a sloped waterfront lot in zone 6a (lots of moisture). The cement garage floor was poured on top of a corrugated metal floor deck held up with steel I beams. Under the main garage floor is a decent space that I'd like to finish and heat (unsure if I'll ever heat the rest of the garage). Spray foaming the underside is one option I would assume but its costly. Would polyiso foil faced boards be an option if the seams were well taped or foamed?

Very much appreciate this forum and any feedback!

Asked By P Stone | Apr 25 17
1 Answer

Will pocket door gaps at jamb allow avoiding a transfer duct?

Hi there: I'm trying to calculate undercuts necessary for balancing an HVAC system in a couple new residences. But then it occurred to me, that since all the doors are pocket doors, and since the Johnson Hardware we're using specifies a 3/16" gap between the jambs and the door panel on either side of the door, that this gap could be considered a "transfer grille" of sorts... The smallest 30x80" door would therefore have the equivalent of 20in2, not including any undercut.

Am I thinking about this in the right way? Do these 3/16" gaps give me what I'm assuming they do, in terms of airflow?

Asked By jonathan nagar | Apr 25 17
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