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5 Answers

Double wythe CMU vs. Thermomass

After living in Europe for several years I have become a fan of concrete. I build in the Southeast and have mainly used concrete commercially and as stem/foundation/retaining walls and for slabs in residential.

Asked By leo kloop | Oct 22 14
12 Answers

Thermal energy storage

~3900 square foot house.

I am thinking of building a water based TES tank using ICF in a crawl space.

The plan would be to use RV antifreeze in an active (pump) circulating heat exchanger that sits at the bottom of a tank of water. Domestic water supply would pass through another heat exchanger that sits at the top (for stratified water column effects) inside this tank and preheat water for radiant hydronic boiler and domestic hot water.

I was thinking 12'x12' @ 6' tall for a 864 cubic foot / 6463 gallon tank.

Asked By Jim Pancanke | Oct 21 14
4 Answers

PERSIST vs REMOTE vs SIP ?

We are building a new house in MN (6b), considering various wall systems, and trying to get a handle on the pros and cons of each. Thus far we have:

SIP Pros
- Better known construction method, easier to find carpenters, ...
- Well documented construction details

PERSIST Pros
- Seems like it would be easier construction than SIP.
- Easier to get all details correct.
- Provides significant interior space in attic for ducting, extra room, storage areas, etc.
- Chemical elements (foam, osb, etc) on outside of air/vapor barrier

REMOTE Pros

Asked By Walker Angell | Oct 21 14
34 Answers

Options for high R-value above-grade walls (R-80)?

To make a long story short, my above grade exterior walls need to be at an R value of 80. This is to meet Passive House standards for a new residential house in a very demanding climate.

I am currently planning on using SIP's of some sort. But even the best of those only get me up to around R-50 though. Any thoughts on ways to get to R-80 while still being cost effective and keeping the size of the wall to a minimum?

I have found a number of options myself, but was curious if anyone else had thoughts or suggestions to meet such a high R value for a wall.

Asked By Tom Schmidt | Sep 19 14
1 Answer

Vented roof insulation

For a vacation home in a 5b zone, does it make sense to put exterior rigid insulation (1" xps) under a standing seam metal roof? This will have a vented attic with no mechanicals up there. I anticipate blow-in on the ceiling deck.

Asked By Robert Holland | Oct 16 14
10 Answers

Roxul Comfortboard - disadvantages?

I'm intending on insulating my 1950's Cape style house with exterior insulation. I've been planning on following the CCHRC's REMOTE wall assembly with an air tight membrane over the sheathing and 6" of EPS foam (2, 3" layers) then furring strips and siding.

Asked By Mark Fredericks | Oct 14 14
9 Answers

Building science options

looking for advice on options on getting into building science & green renovation ---- it seems there is still a disconnect between the building science research and the builders in the field.

Quick background on me --- I have a Chemistry degree and taught the subject for 8 years before leaving the field to be a remodeling contractor --- so I am very interested in the science behind renovating from an energy standpoint.

Asked By Jason Schatz | Oct 5 14
21 Answers

Interior vapour barrier with exterior XPS

I am in the initial stages of house design.

I am thinking of a double 2X4 wall construction with 2": of XPS on the outside to minimize thermal bridging.

My concern here is that building code here in Ontario requires a vapour barrier on the warm side wall

I suspect that the combination of XPS on the outside and 6 ml plastic on the inside will cause any water that might get into the wall cavity to stay there and not have any where to go .

Question : How do I get my wall to dissipate water in this design ?

Steve

Asked By Steve Babcock | Oct 3 14
12 Answers

Is external polyiso worth the cost?

First, let me say, that this community is fantastic. It is good to see so many people invloved and really dedicated to making building more efficient, and thus, playing a part in saving our planet and environment. I am always pleasantly surprised at how helpful everyone is, most of all, you Advisors. Thanks for the time and effort.

Asked By Kurt Samson | May 19 10
4 Answers

Sealing gap between garage floor & drywall?

Hi:

I am trying to figure out whether & how to air seal the gap between my garage floor and drywall in my 12-year old three-story townhouse in zone 2a. The gap is generally 1/2" wide, however in many places it's less. The door shown in the photos leads to the first-floor of the house.

I think caulk (any particular kind?) is the answer, but wanted to check first.

Also curious - without performing a blower door test, how "bad" do you think this gap is from an air-sealing perspective?

Thanks,
Rob

Asked By Robert Hallenbeck | Sep 20 14
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