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A Forum of Green Home Building Experts and Members

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Much of the value of this site is the pooled experience of members and their willingness to share it. One way is by using the comment boxes that follow every post. This page offers a Community area formatted for Questions & Answers. Please notice on the right that we've divided the Q&A forum into topics to make it easier to find your area of interest.

Anyone may ask a question--about anything within the realm of residential green building--and anyone may answer. Sometimes one of our 15 Advisors may chime in; in other cases, you'll get the wisdom of some of our members who have experience with the detail, material, code, etc. that prompted the question. We encourage everyone to give us the benefit of both their questions and answers. The usual rules of courtesy apply.

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27 Answers
AFFORDABLE Low Energy

Forget about Spray Foam
Forget about Conditioned Attics
Forget about Vaulted Ceilings

Provide a Simple(and rigid) Air Control Layer
Add Ventilation
Add a Thermal Control Layer
Add Cladding Structure and Roof Structure
Add Replaceable windows and doors and Sacrificial Claddings

Cladding structure can be as simple as furring strips

In Energy efficiency and durability | Asked By John Brooks | Feb 5 10
3 Answers
How to make my 1966 home more thermally efficient?

I am retired and faced with very large heating bills. The weather in NJ has been quite cold and snowy for us. Our home was contractor built
in 1966. 2x4 walls with 3" on insulation. The windows are wood but not as tight as today, but the stroms windows leak to a point that we get snow
between them and the window. The house is a colonial salt box, The front is one storey, two stories in the rear. There was no insulation in the frount. I have tried to put some over the years but not sure how much good it really does.

With limited funds what is your guess as to the place to start.

In Energy efficiency and durability | Asked By Tom Spang | Feb 8 10
9 Answers
Drying to interior and paint

Hello all,
I've been learning all the Building science I can lately, and of course, that leads to questions! Hope folks here can entertain a few.
Here is one question I'd love some feedback on.
Consider a New England home that is to get outsulation, or exterior foam insulation in retrofit, or new construction. Almost all outsulation details create a vapor impermeable surface, and thus the wall is then expected to be able to dry to the interior.
How many coats of paint can a gypsum board wall take before the perm rating gets so low as to be risky?

In General questions | Asked By Nathaniel | Feb 3 10
5 Answers
Software for Builders

When I was getting out of building and remodeling, I had a website with password-protected places for customers to log in and view documents/photos related to their jobs. I was too cheap to buy estimating software, so I made spreadsheets to estimate things like lumber and drywall. There was no SketchUp, so I drew everything by hand. One builder I know used to set up a fax machine on the job site so the design team could fax detail drawings over.

What kinds of software do you GBA members use to design/build/remodel homes?

Estimating?
Project management?
CAD?
Accounting?

In General questions | Asked By Daniel Morrison | Feb 6 10
3 Answers
Combination DHW and Space Heating

I'm interested in learning regarding the feasibility and advisability of using a hybrid "small tank" condensing or tankless condensing hot water heater to provide both DHW and space heating for new construction in a heating climate. Examples include Navien America 180/210/240 (EF .98-.95), Eternal GU195 (EF .96), Takagi TH2 (EF .93), Rinnai RC98HP (EF .93), Quietside ODW199 (EF .92), or Noritz NCC199 (EF .92).

In Mechanicals | Asked By Jan Juran | Feb 8 10
7 Answers
Cost effective exterior wall construction.

In exploring options for a cost effective R-40 exterior wall in a cold climate (Western Massachusetts), I am left scratching my head. As a residential designer, I have researched Building Science's website and their High R wall systems, where multiple layers of rigid insulation and a thermal break is their obvious choice. However, when clients want shingled siding and decorative trim, I want the sheathing on the exterior face of the rigid for consistent nailing. In addition, my structural engineer wants the sheathing directly nailed to the studs for shear (100 mph wind speed).

In Green building techniques | Asked By Jon Wyman | Feb 1 10
6 Answers
Contrast plywood window RO extensions with other method?

Hello folks,
I wonder if I could get some discussion on the pros and cons of two window methods with outsulation.
I've seen the plywood RO extenders used.
Contrast that with:
(for a 2 in exterior detail) 1 layer of foam right to window RO, with the RO then surrounded with 1x 3+/- as an attachment surface for the window flange. Second inch of foam buts up to the wood around the RO.
Similar situation for thicker foam I suppose.
Thanks!
Nathaniel

In Green building techniques | Asked By Nathaniel | Feb 3 10
17 Answers
Did an add-a-level, insulation options are of concern with solar panels

I have just completed an add-a-level on a New Jersey cape cod home and am at the point where I need to decide how to treat the insulation issue up there. I might add that there is a furnace up there in the attic with lots of ductwork which the installer wrapped. The south facing roof will be completely covered with solar panels. The existing insulation on the first floor is admittedly not the best, but short of ripping out all the walls there wasn't much I could do that I was aware of.

In Energy efficiency and durability | Asked By Monica | Feb 6 10
15 Answers
Hybrid Insulation Techniques

Many insulation companies in our area have begun to sell hybrid insulation systems. In a standard 2x6 wall, they will spray 1" of closed foam inside the wall cavity and then fill the rest with cellulose. The idea is to get all the benefit of the air sealing, but then to get the rest of the R-value from the much less expensive cellulose. I can foresee many potential building science issues with this, but it's hard to compare to anything out there.

Does anyone have experience with these systems? How do they perform? How is their durability?

Thanks.

In Energy efficiency and durability | Asked By Adam Stenftenagel | Mar 2 09
5 Answers
Green Permits

I learned today that a couple of builders I work with "volunteered" me to meet with one of our local Codes Departments next week to explain, and possibly help develop the process for, a streamlined Green Permitting Process. While there is good information here in the Code Green Blog, I am curious if anyone else has been through this process with their Codes Department? If so, I would appreciate any comments or suggestions related to your experience.

In Building Code Questions | Asked By Grant Dorris | Feb 4 10

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