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6 Answers

2nd story addition heating

We're working on an addition to a 740sf 1940s home in Portland, OR - addition includes +300sf on main level and new 2nd floor (1300sf). The existing furnace is brand new high efficiency gas, but not enough capacity for the addition. The owners do not want to replace it since it is so new. We are in the process of value engineering to bring costs down, but need to evaluate how to heat the new 2nd floor. Cost is an issue, but could possibly persuade them on a good investment.
Insulation: R-49 flat ceilings/R-30 vaulted attic storage space, R-23 walls.

In Mechanicals | Asked By Miyeko Endy | Jun 26 14
2 Answers

Poly under panelling ?

I have a camp that I use mostly in the summer, but some in the fall/winter, that I have: insulated the floor, will spray foam the cathedral ceiling, rebuilt the walls with (outside – in) 19/32” T1-11 sheets (stained), 1 x 3 strapping (vented air space), Tyvek house wrap, 7/16 OSB, 2 x 6 studs, Roxul R24. And now I’m stuck. I have read many (most) of your articles, etc.

In Green building techniques | Asked By David Beals | Jul 1 14
2 Answers

Cedar poles for verandas

We live in New Zealand. We want to use our home-grown cedar poles for the veranda but cannot get council approval.

We have some cedar whole tree poles. They include soft outer wood but are 25+ years old and have a minimum of 80 mm heart. They are protected from the weather by the verandas, but because I grew them on my property and they don't carry a durability and strength certification, the building inspector will not sign them off.


In Building Code Questions | Asked By Pete Davies | Jul 1 14
12 Answers

Anyone use Glass Fiber Reinforced Polymer GFRP rebar in ICF or poured concrete walls?

I'm intrigued with the possibility of using Glass rebar instead of steel. Largely because I don't want to be surrounded by a large metal cage that could be doing various unhealthy things to us from an EMF (electro-magnetic frequencies) perspective. Also because I don't want corroding steel in my walls.

However, I can't get my head around the EMF implications. Do I actually WANT a metal cage around me - like a Faraday cage? Does it protect us from EMF's? Or does it make them a bigger problem?

Any EMF experts out there?

In Green products and materials | Asked By Zenon Tymosko | Aug 20 13
2 Answers

Difference between Climate Zone 5 and 4 Marine

We are working on a 5 story wood framing over concrete podium senior living facility in Thornton, Illinois. I am trying to understand the difference between Climate Zone 5 and Zone 4 Marine.

Looking at the Blog Post on this website, "Calculating the Minimum Thickness of Rigid Foam Sheathing", the table on the second page lists the recommendations for Foam Sheathing Thickness, and there is a considerable difference between the Climate Zone 4 Marine, and Climate Zone 5? But, each map I have looked at shows that Cook County, Illinois is both/the zones are the same?

In Energy efficiency and durability | Asked By Andrew Buck | Jul 1 14
3 Answers

WRB for a fiberboard wall assembly?

I'm building a house where the exterior walls have been sheathed with a bitumen treated structural fiberboard. I have two questions:

1. Should I tape the seams of the sheathing on the exterior side of the wall? If so, with what?

2. What is the best WRB for this type of wall assembly... building paper or Tyvek/Typar etc.?


In GBA Pro help | Asked By Daryl Ross | Jul 1 14
1 Answer

Due to aesthetics, R-20 (4 1/2 inches of rigid foam) above the roof is my limit

Due to aesthetics, R-20 (4 1/2 inches of rigid foam) above the roof is my limit. Would Roxul plus an airspace in the rafter bays be a good choice for the remainder of the needed R-value?

Jesse, 80% of home is concrete slab with remaining 20% being crawl space I closed in - conditioned basement. In a high water table area with no vapor barrier under slab or crawl. De-humidifier runs constantly.

I plan to include air space in rafter bays under sheathing along with batt insulation for remainder of needed R-value. Is an airspace necessary with R-20 foam above roof sheathing?

In Green building techniques | Asked By cameron morris | Jul 1 14
8 Answers

Another Hole(s) in the... Wall

My Northern zone 5a home can't be a Passive House (PH) because it was built in the 50's. But I'd guess that imitating PH practices where possible as projects are done will help the house be the best it can without a gut rehab.

In PassivHaus | Asked By Gordon B | Jun 23 14
1 Answer

Crawl Space

Hello, I need help! I have a small one story single family home. We removed the old/damp insulation and I need to know if I should close off the vents and put a dehumidifier in the crawl space? I do have a vapor barrier on the stone ground, but there still is moisture and some signs of mold! We did put a sump pump in there last summer. What should I do, this property is in Annapolis MD.

In General questions | Asked By Lynn McCreary | Jun 30 14
4 Answers

Insulating I-joist cathedral ceiling with Roxul

I have decided to use Roxul to insulate my cathedral ceiling constructed of I-joists on 24" centers.
The Roxul should be encapsulated on all sides.
I will be leaving a ventilation cap at the top of the I-joists, utilizing the flange as the spacer.
I was planning on using the steel stud version because it is 24.25" wide.

I first thought of using 1" XPS as the air sealing, cut to fit between the webs, caulked and taped.
I was wondering if using something like Tyvek sealed and stapled to the underside of the flange instead of the XPS?

In Green building techniques | Asked By Aaron Gatzke | Jun 28 14
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