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6 Answers

Massachusetts three-decker: energy retrofit during re-siding


In Plans Review | Asked By Al Dhanji | Apr 8 18
13 Answers

How to insulate underside of roof deck in 1927 conditioned space

I have lived here for 18 months. First thing I did was re shingle to roof. Roofer is a pro and said decking was in great shape. Shingles are mid-dark gray in color. This is a 1.5 story home in central MN with the second story "finished" at some point with Homasote on the walls and ceilings. Homasote is a brand name associated with the product generically known as cellulose based fiber wall board, which is similar in composition to papier-mâché. It is in bad condition and needs to come down. There are two unfinished spaces behind knee walls that are accessible.

In Energy efficiency and durability | Asked By Mindy Jost | Apr 13 18
6 Answers

Too small a boiler

Can a boiler which just meets your heat loss be too small to use an indirect water heater? Indirect WH seem to rely on significant amounts of boiler to do the job. If you are at design outside temperature, do you have to make a choice between hot showers or warm house. Is there some point were a standalone water heater is necessary and what is the effect on overall energy use. Oil is my fuel of choice if that matters, no gas.

In Mechanicals | Asked By Jonathan Blaney | Apr 12 18
3 Answers

Performance of polyiso exterior foam at cold temperatures

I've been meaning to post this ever since you helped me out with this question:


One of the last comments by Dana was that in my analysis I should de-rate the foam (especially if it is reclaimed)

"But for unknown goods don't count on it for being better than mid-5s from a design point of view."

In Green products and materials | Asked By Steve Mackay | Apr 17 18
7 Answers

Does Reflectix "Big Bubble" insulation really achieve R-6?

I have seen several discussions here about bubble wrap insulation for ducts (some links below). However, they are all a couple years old, and they don't seem to directly address one of Reflectix's products. The older and smaller products were generally met with great skepticism because they claimed high R values without clarifying that the installation required an air gap between the duct and the bubble wrap.

In Energy efficiency and durability | Asked By huhnra | Apr 16 18
5 Answers

Roof ventilation

I have a low pitch (1/12) single slope shed roof on my house. (Marine Zone 4c near the coast with very little snow and ice) The framing is 2x8 filled with insulation. Drywall on bottom and skip sheathing on top- no ventilation. The existing roofing is built-up asphalt.
I plan to remove the built-up roofing and install 2" of polyiso, then 1 and 1/2 inches of EPS, 5/8" of plywood, then a standing seam metal roof with mechanically seamed joints.

In Energy efficiency and durability | Asked By EASimonsen | Apr 14 18
5 Answers

Product compatibility of wall assembly components for Climate Zone 4a

I am in the planning phases of a new home for my family outside of St. Louis, MO. I'm having a hard time pulling together all the compatibility issues that worry me when detailing my wall assembly. I am striving for a tight house that is well insulated, but not necessarily trying to achieve any recognized benchmark. I would hope that with a future PV array I could be close to net-zero with my goethermal HVAC system planned for. Here is what I am have at least planned for at this point: (from inside to out)

- 5/8" Drywall

In General questions | Asked By Nate Droste | Apr 16 18
13 Answers

EPS, XPS or Polyiso for exterior rigid foam?

Last week I got some great information from this board on my "Taping seams of roof sheathing" question. There was some thread drift there and we started talking about exterior foam and someone suggested I use Polyiso instead of XPS for my exterior foam.

In Green building techniques | Asked By Steve Mackay | Mar 28 18
1 Answer

Best/cheapest way to waterproof a concrete deck?

I have a 20X20 concrete deck above my basement, at the end of my driveway. It is made up of 4'X20 concrete slabs. When it rains, the joints leak. I am trying to turn my basement into a workshop, but haven't because of the water issue. I live in the mountains at 5000 ft. if that makes any difference. I am looking for a way to apply the waterproofing material myself, but everyone wants to do the job for me. Which makes this project prohibitively expensive. I would appreciate any suggestions.

In General questions | Asked By eggdood | Apr 16 18
2 Answers

Insulating a Non-typical Cathedral Ceiling

Insulating a normal cathedral ceiling has been covered by GBA in Martin Holladay's How To Build an Insulated Cathedral Ceiling .

In Energy efficiency and durability | Asked By Steve Robertson | Apr 13 18
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