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4 Answers

Laminate floor underlayment in basement

I built up a basement floor with 3/4" OSB on 1.5" rigid foam over 6 mil poly on concrete slab (per this previous inquiry .http://www.greenbuildingadvisor.com/community/forum/energy-efficiency-and-durability/99205/insulation-basement-slab-question-polyethylene) .The difference this past winter was quite evident. Current question is what to use as underlay for laminate flooring. Some questions:
Should I use a permeable underlay so that the OSB is not encapsulated between the poly/foam layer below and an impervious "3 in 1" underlay above?
Or is conventional "3 in 1" underlay okay?

In Energy efficiency and durability | Asked By Grant Robinson | Mar 28 17
10 Answers

Dual-fuel high-efficiency natural gas / heat pump systems?

Does anyone have any experience with or thoughts on the hybrid "dual fuel" natural gas furnace systems that are combined with an air-sourced heat pump (instead of an AC only unit)?

The intent is for the heat pump to provide heat when its most efficient, but then switch to gas when the outside temperature drops to the point where the heat pump is no longer efficient or effective.

In Mechanicals | Asked By Jonathan Rich | Apr 21 13
6 Answers

Taping seams in plywood for health reasons?

Climate 4C. I am debating the cost and effort of taping our plywood sheathing.

Due to a few circumstances, we changed our building wrap to doubled-up 60-minute paper, attached to furring strips (closed rainscreen). Alternatively we are considering a hybrid product called Hydro-Tex, which is tar paper that has a drainage plane on the backside.

In Green building techniques | Asked By Mike Dominic | Mar 27 17
2 Answers

To housewrap or not to housewrap?

Is housewrap plain and simple overkill?

Wall construction is 2x6 with dense-pack cellulose, OSB sheathing with joints taped (3M all purpose weatherstripping tape), covered by 2-1/2" of insulfoam Neopor EPS which is faced and joints taped (3M 8087).

The original plan was to housewrap at this point, add furring strips, then siding.

I'm wondering if there is any necessity for the housewrap over what is already a water resistive barrier.

In General questions | Asked By Dave De C | Mar 28 17
7 Answers

ERV selection

I've been reading, reading and reading about the various ERV options. Once I think I've narrowed it down, I read a new article or a new model has be released. What is the latest thoughts on the ERV market ranking them from best and also value?

In Mechanicals | Asked By Seth Holmen | Mar 26 17
8 Answers

To vapor barrier or not to vapor barrier?

Hi all,

Pardon my ignorance or lack of proper nomenclature, but have a question regarding vapor barrier/retarder (I know they are not one and the same) and insulation.

In General questions | Asked By jibba1 | Mar 28 17
2 Answers

Dense packing cavities within cathedral vault

I'm preparing to have my attic spray foamed and decided to dense pack the cathedral vault cavities with cellulose. The existing cavities contain batts. Two questions:

1. Is it ok to blow in cellulose on top of the batts or should I fish them out?

2. Should I seal off all the soffit vents (with spray foam) under the eves of the cathedral vault since I'm dense packing the cavities to further prevent any airflow into the cathedral cavities?

3. Should I also spray foam all the soffit vents around the entire house to further promote sealing off any airflow from entering?


In Green building techniques | Asked By uberaustin | Mar 27 17
12 Answers

Building a new house, looking for opinion on insulation/exterior foam combinations

I am currently in the process of designing a new home. I built one four years ago that we have decided is too big and inefficient for what we need. This time around I am looking to build small, simple and efficient. The house will most likely be framed with 2x6 walls, however I would like to maximize R value of that wall.

In Energy efficiency and durability | Asked By user-6801629 | Mar 23 17
8 Answers

EPS foam density for use under concrete slabs and around stem wall

Hi everyone,

I'm right at the point where I need to purchase some EPS foam for our slab foundation / stem wall on a residential net zero project. I've read and posted on the project in the past and there seems to be a consensus that Type II EPS foam should be fine from a compressive strength perspective in both applications.

In Green products and materials | Asked By Joshua Greisen | Mar 27 17
2 Answers

How to vent an attic that has no eave?

In an older building. The problem is ice dams more so than energy cost reduction. The roof design is more complicated than I can explain easily here.

I am considering using these vents. however they look designed for new not retrofit construction. Any experience with this type of vent.


thanks in advance

In Energy efficiency and durability | Asked By Walt Ott | Mar 27 17
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