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1 Answer

Add external rigid insulation to a roof over a cathedral ceiling?

Yes, I know there are many resources on this topic. I’ve done a lot of reading on Fine Homebuilding and Green Building Advisor. I just can’t put all the pieces together.

We have a 30’x33’ 1-1/2 story cape cod with first floor living space, 2nd floor unconditioned space with knee walls and 2 doghouse dormers along the front. 25 years ago we added an extensive low-pitch shed dormer at the back vented to the ridge vent and installed drywall cathedral ceilings in order to add 2 bedrooms and a bath upstairs. No skylights, no recessed lights. We are in southwestern PA, climate zone 5.

In Energy efficiency and durability | Asked By Carolynn Friday | Aug 24 15
3 Answers

Rain screen at soffit detail

CMU house in zone 2.. Hot/humid. Unvented conditioned attic, Rigid foam around rafter tails to underside of roof decking. Cedar shingle sidewall. Verticle and horizontal furring for rainscreen.
Here's the question: There is a plate at top of the wall but due to the slope of the roof the horizontal soffit line falls below the plate line. For added support I would like to run the verticle furring up to and attach to the top wall plate. This means the top of the rain screen will terminate in the unvented soffit.
Do I need...and how do I accomplish ....the top rainscreen vent. Thanks

In GBA Pro help | Asked By Robert Brown | Aug 24 15
7 Answers

What ceiling insulation to protect against ice dams in winter time?

I have very low ceiling less than 8 ft.
I don't want to lower the ceiling. But there are not enough space for insulation.
I wan to use Hard foam to insulate the ceiling having 4 by b joist.
There are two options.
1. Using 2 inch hard Foam(r-13 ) with radiant barrier. (Therefore, there are 1.5inch airspace above the radiant barrier )
I want to install the barrier to reflect inside heat to the room so that I want to make the ceiling being cold.
2. Uisng 2inch hard foam (r-13 )and 1.5inch hardfoam(r-9) together without the radiant barrier. No air space.

In GBA Pro help | Asked By Mansig Yoon | Aug 22 15
13 Answers

How can I solve an uninsulated basement slab energy loss?

I built a supper insulated house on a foundation that was not. I currently live in climate zone 5A in central Illinois, the house itself has R30 basement walls, R40 first floor walls and R60 attic. Double stud framing, air barrier is at the house sheathing. The house itself is 4400 sq ft total of enclosed space, 2100 first floor and 2300 basement. At the moment my home is heated and cooled with a single point source ductless mini split on the main level with a Zhender ERV for mechanical ventilation. It performed pretty well this past winter and does well this summer.

In Energy efficiency and durability | Asked By Joseph Betz | Aug 19 15
2 Answers

Chainsaw retrofit / new overhang detail

Looking for opinions and pics of any added overhangs after old ones cut off. Roof is getting 6" rigid foam and will have 2x4 on top of foam with plywood on top of new 2x4. The 1.5" venting channel will be maintained soffit to peak to reduce possibility of ice dams.
I am in day 5 in my project and starting to stress over the soffit details of overhang and how to maintain the venting. I was planning on using vented drip edge. Any other suggestions?
attached pic is one of few I have found which uses a vented approach. Any links to other photos is much appreciated.

In Green building techniques | Asked By Dirk Gently | Aug 23 15
3 Answers

Freestanding kitchen sink cabinet recommendation?

Can you recommend a retail source for a free standing kitchen sink cabinet that is not MDF or pressboard? Thank you.

In Green products and materials | Asked By Mary Schwaba | Aug 23 15
22 Answers

Is it reasonable to use 3/8" PEX supply lines to all fixtures?

I am planning the plumbing system for my Net-Zero Energy home that is being built to Passive House standards. I will be using PEX tubing with a manifold system using home runs. I designed the house so that the bathrooms and laundry room are centrally located, making the supply runs pretty short. I want to minimize the amount of water and energy being used and low-flow fixtures provide plenty of water for my needs (2.2 gpm at sinks and 2.5 gpm for showers).

In Mechanicals | Asked By Gerald Blycker | Mar 11 14
3 Answers

Hardwood floor installation concerns

Hi, I hired pro installers to install Sound Sound Solution underlayment on plywood (2nd floor of an old farmhouse in Boulder, CO and put down reclaimed 2 21/4" oak hardwood strips. At the end of the installation day, (it was only 300 sq st, a long rectangular condo as 1/3 of the 2nd floor) I come to find out that the installer used Sound Solution's VAPOR BLOC (which I hadn't ordered or wanted), the installer used tubes of titebond (which had not occured to me that such a thing was going to be used), and also no expansion gap was left.

In General questions | Asked By Mary Schwaba | Aug 23 15
4 Answers

Need an insulation expert!

I'm building a new home and it's at the insulation stage. It's 2 story with a steep pitch roof.(8/12 for the main part of house, 12/12 over the garage bonus room and 2nd bonus room over the master bedroom) The attic is vented and has soffits. I'm in zone 2, hot and humid south Georgia.

I had a spray foam guy offer quote 5 inches open cell (r19) on roof line and open or closed cell @ r13.

I'm concerned about not being at code but some literature suggests r20 spray on roof is ok.

In Building Code Questions | Asked By Brock Herrin | Aug 22 15
9 Answers

WRB between panel siding/sheathing and studs in dry, mixed climate?

I'll be building a new, small house in central Arizona, the cooler part of Climate Zone 2B, where summer days go from 70 at dawn to 100 or so in the afternoon and winter nights sometimes drop to 20 with days usually reaching 50. It can get noticeably more humid in the summer "monsoon" season, but nothing remotely comparable to the Southeast. I'll be using SmartSide 4x8 panels as my siding and structural sheathing on 2x6 walls insulated with Roxul batts.

In Green building techniques | Asked By Jeff Cooper | Aug 20 15
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