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8 Answers

Has anyone been successful in fighting their city on not putting insulation on interior brick walls?

We live in MN. We have an 1891 clay brick home. The bricks are dual layer about 13 inches thick and made of clay. The brick is the load bearing walls and the floor joists are in the brick walls. We were originally thinking of spray foam, but after reading the article, we are very scared that if we put any insulation our brick will have freezing & thawing and deteriorate. We have gutted all of the walls of the lath and plaster, so we have access to insulate, but do not want to ruin the brick. We would like to appeal to our local building officials so not be required to insulate.

In Energy efficiency and durability | Asked By Kristina Beedle | Feb 24 12
4 Answers

Our house was built using salt water

Does the salt water make any bad effect on walls and iron rods used in concrete ?
if so how to control it?

In General questions | Asked By madhura mohanraj | Feb 24 12
6 Answers

Retrofit rigid foam outside CMU walls

I'm looking for resources to plan a retrofit of rigid foam insulation outside our walls. The vast majority of resources are about wood framed walls, but we have walls built from concrete masonry units (CMUs).

In Green building techniques | Asked By James Howison | Feb 21 12
29 Answers

Am thinking of the following wall and roof assembly in BC as a cost effective way to achieve a high R-value and tight envelope.

2x6 structural wall with roxul in the cavities and gaps in sheathing (drill holes as well) to promote drying to exterior. The inside of this wall is sheathed with 1 inch of polysio (air and moisture barrier). A 2x4 wall inside this provides chase services, a cavity for fiberglass batts, and protection of air barrier.
The 2x6 walls are straightforward construction, with most of the building wrap and rainscreen installed before lifting wall. Foam insulation is also easy to install with no penetrations.

In General questions | Asked By Reggie DuBois | Feb 14 12
6 Answers

Unvented attic with open-cell spray foam

Newbie here with a design question. Planning a retirement home about one hour west of Ft. Worth, TX, (Gordon,TX) climate 3B I believe. Having trouble with the proper unvented roof design using, as I'm told by most of the approved builders in my development, open cell sf (spot leaks if any develop). What are my most practicable, cost efficient methods of :

1) achieving my required R code value in the roof (R38 roof/R15 walls per USDOE website)
2) eliminating thermal bridging (if that is a concern in climate 3B?)
3) Use ADA air sealing of sheetrock

In Energy efficiency and durability | Asked By John Grutta | Feb 21 12
15 Answers

Assistance with Attic Mold on my clients' home

Let me start by saying that I am sorry this is going to be such a long post. But I have spent countless hours over several winters now trying to assess this problem. And I guess I feel that for any of you to be able to give me an informed opinion as to the cause(s) of my problem and any subsequent suggestions/solutions, I have to give a thorough explanation of the project background and site conditions. I’ve also attached a few photos to help visualize the situation. And so I come to you GBA experts, on bended knee, in the hope that you can generously impart some of your wisdom.

In Green building techniques | Asked By Christopher Fuller | Feb 17 12
3 Answers

Dual fuel heating system - thermostat?

We recently built an addition onto our house and instead of extending our existing AC-only system, we installed a second AC/heat pump system. The house also has an oil-fired boiler with baseboards.

We added two heating zones to the addition onto the existing hydronic heating system, so the addition has two heat sources - oil and heat pump.

In Energy efficiency and durability | Asked By Eric Yancey | Feb 21 12
6 Answers

Solving thermal bridging.

I am building a wood frame home in southern Maine. I am using a combination of 2" spray foam and unfaced fiberglass batt in the exterior 2x6 walls for a total of R25. Would installing 3/4" rigid foam board insulation between the exterior 1/2" sheathing and the cement board siding create any moisture issues in the sheating, given there is spray foam on one side and rigid foam on the other? I am concerened about thermal bridging.

In Energy efficiency and durability | Asked By Dana St.Ours | Feb 21 12
4 Answers

Planned communities

At a social event last night, a friend who owns a 25-acre parcel asked me about resources for developers (or groups of friends) thinking about building a cluster of houses where like-minded people can live near each other. My friend is wary of the endless meetings associated with co-housing, and is also aware of the issues that arise when a group of friends build adjacent houses, only to have situations change due to divorce, deaths, and inheritance.

So who can recommend Web resources discussing these issues -- questions about:

1. Subdividing land

2. Intentional communities

In General questions | Asked By Martin Holladay | Feb 20 12
1 Answer

Thermal mass volume

Another related question: When measuring square area of the floor that may receive sunlight, do we include all of the uncovered floor area next to the south facing windows, even though some of the floor, like that abutting the south wall, will never get direct sunlight?


In Green building techniques | Asked By Christa Campbell | Feb 21 12
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