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7 Answers

Filling cinder block with pea gravel?

I am wanting to build a house on some land I bought in Florida. I plan on using cinder block for my outside walls covered with stucco. I want a very high r value. Can I fill the cinder bock with pea size gravel to give the wall a higher r value? What would be the positive and negative implications in doing this?

Thanks, Gregg Webster

In Green building techniques | Asked By Gregg Webster | Jun 15 15
7 Answers

Air source heat pump water heater in a small mechanical room

I am building a 2-unit addition to a duplex in Portland, OR, resulting in a 4-plex. The new units will be largely separate from the old, and will be built to PH-like standards (very tight air barrier, heavily insulated). With an eye toward economy, I am thinking for the 2 new residences to share a mechanical room. In this mechanical room would be water heater(s) for both new units, along with an HRV (likely Zehnder 550) serving both units.

Relevant plans and considerations:

In Mechanicals | Asked By jonathan nagar | Jun 15 15
3 Answers

Attic ventilation

Many people where I live have installed solar roof fans to help with their existing roof ridge vents...is this OK, can this cause problems for the roof or shingles ?

In General questions | Asked By Paul Osmer | Jun 18 15
2 Answers

How to reduce summer heat highs with insulation and ventilation in a conditioned attic with 2x4 roof rafters?

Hi there,

In Energy efficiency and durability | Asked By John Lindner | Jun 19 15
1 Answer

Need help finding blog post about various construction methods

A year or more ago I read a blog post or article somewhere discussing the various types of construction methods and why high performance construction methods were better than the other methods.

It compared methods like cob houses, earthship, straw bale and basically led the reader to passive/netzero/pretty good methods as being the best from a user and owner standpoint based on construction costs, conventionality, resale value and other factors.

Can you link me to this article/website/blogpost?

In Green building techniques | Asked By Joseph Malovich | Jun 19 15
1 Answer

Adding exterior rigid insulation to Superior Walls

Martin - do you know if it is advisable to add extra exterior rigid foam to Superior Walls? I looked on their website and it only mentions adding insulation to the interior stud bays. But this doesn't resolve the thermal bridging issue through the concrete studs. Would there be any moisture issues if I'm effectively creating a sort of poor man's ICF? Any suggestions for attaching this? Superior walls high psi concrete is notoriously hard to penetrate evidently. Is it ok to just press them against the walls and have the backfill hold them in place? Thanks to anyone for any suggestions.

In Energy efficiency and durability | Asked By Brian W | Jun 18 15
15 Answers

Planning a new double-stud house — what should I change?

My wife and I are planning a 2,100-square-foot house in Massachusetts. Here's the plan: a south-facing wall with glazing equal to 13% of the 1st floor area. A 5" radiant slab on grade with 4' frost wall on footings insulated with 4" of xps underneath with a stepped foundation top to minimize thermal bridging.

We were planning a 10 1/2" cavity double-stud wall with dense-pack damp-spray cellulose and lots of air sealing. Huber Zip System exterior sheathing with strapping and vertical pine siding sealed on all sides for a rainscreen wall.

In Plans Review | Asked By noah kaput | Sep 15 11
7 Answers

I lapped cedar siding over Roxul ComfortBoard

In our area, I have seen a siding detail where they use horizontal 1x4 cedar boards with something like a quarter inch gap between the boards. They don't look like ship lap. I am assuming that they have been fastened directly to the rain screen.

However, I wanted to install 1.5 inch Roxul ComfortBoard on top of the WRB and then the rainscreen. I guess my concern is that this siding style is not a water shedding design.

Does anyone have any experience with this siding style over exterior insulation.
Or have any suggestions on how it could be done?

In Green building techniques | Asked By Aaron Gatzke | Jun 18 15
1 Answer

Is this 2012 code already enforced for TX ? - whole-house mechanical ventilation system

Is the requirement of "whole-house mechanical ventilation system" for Code 2012 already being enforced in TX ?
Is it mandatory in the state of TX now ?
If so, can you send me copy of that section for Code 2012 or which website to locate it please ?

Thank You,

Darla Kay

In Building Code Questions | Asked By DARLA KAY | Jun 18 15
1 Answer

Mini split condensate - dense pack lesson learned

I built a pretty good house last year, heated and cooled by a 12k btu Mini Split on 1st floor and 9k btu Mini Split on 2nd floor. Toward the end of summer last year our first floor unit was not draining condensate then after partially insulting our basement ceiling with dense pack cellulose, our 2nd floor unit was not draining at the start of this summer. Long story short, after investigating many ideas to the root of the problem, we just recently discovered that the flexible condensate line was pushed around when I dense packed basement ceiling.

In Mechanicals | Asked By Christopher Vernott | Jun 17 15
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