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4 Answers

Ray-Core panel wall detail help

I’m building a pretty simple 24’x30’ timber frame camp on a walk out foundation in western Maine (6A). Basement - unfinished, first floor - one bedroom and bath, then rest open to above, 12’x24 loft. It will have a 12/12 roof. I’m doing as much of the work myself as I can.

I’ve purchased Ray-Core (raycore.com) polyurethane foam insulated panels, 3.5 (claimed R26 – I know, I know, but let’s not go there) in for the walls and 5.5” (claimed R42) for the ceiling.

In GBA Pro help | Asked By Michael ONeill | Jun 16 12
8 Answers

Unvented roof problem

I built a great room addition but didn't do my homework first. The outside of the roof is finished.

Due to weird angles, dormers, hips, etc., it is virtually impossible to vent this thing. Also due to all the weird features, the roof deck was completely covered with Ice & Water Shield before the metal roof was installed. So now I can't add foam to the outside, and the Ice & Water Shield will prevent any outward drying.

What do put in the 2x10 rafter bays that will work in zone 6? I was trying to avoid spray foam due to the cost, but is this my only option?

In General questions | Asked By darren williams | Dec 10 13
4 Answers

Stick-built truss on platform-framed attic?

In reading a blog on venting roofs by Joe Lstiburek from a few years ago --


-- the reader's discussion briefly turned to a method of creating an air barrier in the ceiling by sheathing the ceiling joists with OSB or plywood, then building the roof on top of that platform. In comment #6, John Brooks posted a construction diagram of one such system (see attached).

In Green building techniques | Asked By Jack Woolfe | Dec 12 13
3 Answers

DC-powered deep well pump

We have a 6" deep well - currently powered by 220V house power (that won't work with my 5KW genny - for reasons I cannot fathom).

After losing power again this weekend from the rain/ice storm - its time for an alternative.

So my question:

Would it be better to get an inverter and use the current AC powered pump - or change out the pump to a DC powered pump?

I have done a bunch of research on this and am not finding a definitive choice either way.

Appreciate any guidance.


In Green products and materials | Asked By Sean Cary | Dec 11 13
9 Answers


I just want to ask a question which I'm sure other people want to ask.

Why is this beautiful, valuable website so dysfunctional? Why is it completely off at night and on weekends, and why does it get so many gobbledy-gook spam questions late in the day?

This has been going on for years. What will it take to make this website work? Why does a first-class operation like Taunton allow this to go on?

In General questions | Asked By Gordon Taylor | Dec 11 13
4 Answers

Exterior polyiso or XPS for wall and roof assembly?

I have plans for construction of a 15 x15 foot addition to my home in climate zone 5. The walls are currently designed as 6-5/8 inch Murus OSB polyurethane SIPs with adhesive spray foam in the panel joints, All Weather Flashing tape on the inner seams and Grace Vycor adhesive on the outer seams. Tyvek Drain wrap is over the SIPs to act as a small air gap. The drain wrap is covered by 2 inches of foil faced polyiso with 1x4 furring added to support UNA-CLAD steel siding. The entire wall assembly is roughly R 53 or so.

In Green building techniques | Asked By W. Timothy Ward | Dec 11 13
1 Answer

Roof truss insulation

Hi, I am building a detached 24x24, on slab, single story, 8' walls , two gable, 4/12 pitch shingled roof, brick veneered, workshop. This will be a unheated workshop. I live in Charlotte NC. This is zone 3.
Anyway.. R15 glass batt insulation is going in the walls under drywall. Since I will NOT have an attic, and NOT be using drywall to cover the bottom cords of the trusses, the 4/12 roof trusses will be visible and are spaced at 24" apart.
Here is my plan for the upper insulation.
Visualize from the shingles down,
felt paper,
osb roof deck,

In Energy efficiency and durability | Asked By Greg Stringer | Dec 12 13
2 Answers

We built a "pretty good house" in Jefferson NH this year and are getting condensation on the interior of the windows.

We have 3 layers of 2.5" XPS with staggered and sealed seams on the walls and 4 layers on the roof. So 7.5" and 10" respectively. The interior stud cavities have been left open and empty. The windows are set as "outies" and the doors as "innies" and space between the studs/plywood boxes and the doors/windows were filled with cans of window and door spray foam. The house is heated by two mini splits and has been performing very well to date. It is a vacation home and when we come back after a week plus away there is condensation at the bottom of the glass of the window.

In General questions | Asked By james magner | Dec 12 13
4 Answers

Why are my windows wet?

4 year-old 2800 SF home in Duluth (zone 7A). Very tight construction, Well insulated etc. Using a Venmar HE1.8 HRV running full blast. We still have 1-2 inches of condensation and some ice along the bottom of our windows when the temp is <0F at night. (low-E H-windows).

Is our HRV sized too small, or am I doing something wrong?

In Mechanicals | Asked By Jeffrey Lyon | Dec 11 13
2 Answers

Minisplit blowers mounted low or high?

When your primary need for a minisplit system is heating rather than cooling, would it make sense to mount the blower low (near the floor) rather than high (at the ceiling)? I spoke to someone at Mitsubishi who explained that they were designed to go high, even for heating. But I don't totally buy it. Why design them that way if heat rises?

In Mechanicals | Asked By Daniel Herskowitz | Dec 10 13
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