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9 Answers

Roofing underlayments

In a truss framed cathedral ceiling with R-60 cellulose and continuous vent channels from soffit to ridge, how important is the permeability of the roof membrane with a charcoal colored asphalt shingle roof?

Location; Western Massachusetts - Climate Zone 5, 7928 HDD

In Energy efficiency and durability | Asked By Jon Wyman | Aug 6 10
1 Answer

Recommend make-up air/heat exhaust fan

Looking for 8 foot hood with a make-up air/heat exhaust fan
Any suggestions or recommendations?


In General questions | Asked By Bet Stepney | Jan 25 12
10 Answers

I’m working on the design of a two story house in Climate Zone 5

I’m working on the design of a two story house in Climate Zone 5 for a client with a somewhat limited budget. (I’m attaching a dwg showing the schematic section)
There are a number of different conditions in the house.
The main roof over the Second Floor will be a low slope EPDM roof pitched at ¼” per foot. The ceiling of the second floor is located at the bottom of the trusses.
There is a small portion of the house that is one story and covered by a shed roof with a metal standing seam roof that meets a higher wall.

In GBA Pro help | Asked By Linda Gatter | Jan 23 12
7 Answers

Are HVAC ducts a factor in heat loss?

I am in the whole house fan business (http://www.invisco.com) and just released an R60 duct adapter. I notice that there is nothing like it for HVAC ducts. Are those ducts too small to be of concern? My design can be used to add insulation to ceiling connections to meet R38, R49 and even R60 for hvac ceiling interfaces if that would be of value.

In Energy efficiency and durability | Asked By Kurt Shafer | Jan 23 12
4 Answers

Insulation for Vented Cathedral Ceiling

Hi all. I know the issue of insulation for cathedral ceilings has been addressed before, but I am still confused by what the best approach is for a vented cathedral. I live in Westchester, NY. We currently have 3 large skylights in our great room. One has developed a bad leak, so we have taken down much of the ceiling and are now considering the choice of fixing them or eliminating them. The beams are 2x10s, which currenly have about 10 inches of fiberglass batts. there is no vent channel against the roof, so I assume the air just moves through the fiberglas.

In Energy efficiency and durability | Asked By Richard Cohn | Jan 24 12
0 Answers

A great new introduction to air sealing

Credit where credit is due: the U.S Department of Energy's Building American program has done a great job with their new introduction to air sealing:
Air Sealing: A Guide for Contractors to Share with Homeowners

Check it out -- it's good.

In Energy efficiency and durability | Asked By Martin Holladay | Jan 24 12
23 Answers

Insulation- rim joist area?

Keeping with the theme of the week-- not-so foamy homes-- I am trying to come up with a solution for insulating a rim joist area with open web floor trusses that does not include foam.

Has anyone tried to wet spray cellulose onto the rim joist between/around the floor trusses? I would imagine that wet sprayed cavities need to be incapsulated on all six sides to avoid settling, but I could wrong about this.

Dense packing the area with insulweb and cellulose would a nightmare-- it would be dang near impossible to fasten the insulweb around the webbing of the floor trusses.

In Energy efficiency and durability | Asked By Brett Moyer | Jan 13 11
4 Answers

Basement rigid insulation

Im installing 2”xps against concrete basement walls using insulation adhesive and foaming gaps. However, bracing the rigid panels while the adhesive sets up is proving time consuming. Can I use a concrete screw and washer to brace the panel? Best practices appreciated.

In Green building techniques | Asked By Frank O | Jan 23 12
7 Answers

Newbie questions


This may be a little odd question for you experts here but I'm making house vs condo considerations and the major factor is the heating costs which are included in the condo maintenance

In General questions | Asked By sam dhak | Jan 20 12
59 Answers

Heat Bridge or 3-Dimensional Pressure Boundary?

I stumbled on this interesting image a while back.
I noticed that the caption refers to "heat bridges from structure and roof fasteners"....
The fastener locations are obvious....
But the linear pattern does not look like a structural pattern(series of wood or steel rafters or joists).
It looks more like a pattern of rigid insulation and the voids between the insulation.

I think the pattern is more likely related to 3-dimensional Air flow as mentioned in this Insight

In Energy efficiency and durability | Asked By John Brooks | Dec 23 11
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