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4 Answers

Off-label use for open cell Iso foam?

GC is proposing to use Iso open cell foam as bulk fill in lieu of compacted gravel / sand fill over existing residential interior concrete slab on grade, to provide a base for a new interior concrete slab. Requirement is to bring a 15' X 19' X 12" deep "ashtray" up to level with surrounding floors and finish with tile to match adjacent. Application is strictly structural; insulation value is not a benefit. Existing recessed slab is 4" above base flood elevation including freeboard, existing plumbing drain pipes are below the existing slab.

Asked By Leslie Divoll | Feb 12 16
6 Answers

Does anyone have experience with Zehnder ComfoFlex?

We are building a new house and in the final stages of design. The design includes an HRV and Zehnder ComfoTube looked great until I discovered that it is not UL listed. So, I'm curious if anyone can provide feedback on ComfoFlex. There isn't much on the intertubes...

Asked By Trevor Fontaine | Feb 9 16
2 Answers

Will I do more harm than good adding unfaced polyiso in my exterior walls?

I am building a two story home trying to balance efficiency and cost. Outside is Hardie board strips that look like natural wood boards. Under the hardy board is TyveK, no additional insulation outside. Could not afford zip guard so we used standard particle board looking sheathing. 2x6 walls 16" on center.

Asked By Mike Shultz | Feb 12 16
5 Answers

Duct manifold for a stand-alone ERV

I'm trying to figure out the best way to install my ERV ductwork. I don't have a forced air system, so each supply or exhaust will have it's own duct. I have seen the typical trunk/branch method, but a manifold system seems easier. Does anyone have experience with building a manifold system for mechanical ventilation? I will have three exhaust ports and four fresh air ports. I've looked at the Zehnder systems and they look pretty slick, but I cannot afford the price. I am leaning toward Thermaflex ducts, which are high quality flexible ducts usually used in commercial applications. Thank you!

Asked By Adam Emter | Feb 9 16
3 Answers

Sealing and insulating hatchway to vented attic

My attic is now insulated with 18" of cellulose. The builder left a hatchway from a closet in case we need to access the attic -- it will not be used for storage, just for access if something goes wrong. The builder suggested using a piece of plywood with a couple sheets of foam insulation on top to cover the hatchway.

Does that make sense? How can it be air sealed so that it is not a chimney sucking up warm air? Would weather stripping suffice?

Asked By David Martin | Feb 12 16
8 Answers

Raised-heel trusses can be annoying

We installed raised-heel trusses with bottom chord overhangs on our house. The top of the top chord is 20" above our top plate. According to the 2012 International Residential Code for seismic zones or zones designated for winds of 100 mph, raised heel trusses more than 15.25" have to be blocked and braced.

Asked By Jimmy Nguyen | Feb 6 16
1 Answer

German flangeless window install and flashing details

I have an upcoming job with German tilt turn windows, they don't come with flanges like US windows typically do. My install plan is to screw through the frame (unless someone has a better idea) and once installed I am not that concerned about getting them air sealed. What I am trying to figure out is what is the best way to integrate them with the WRB and make sure they are not going to allow water into the home? Anybody know of a manufacturer who publishes good instructions for this? Maybe a German site that shows the materials and steps? This particular manufacturer does not.

Asked By Bob C | Feb 12 16
5 Answers

Can unvented roof assemblies be insulated with fiberglass if I use rigid foam on the exterior of the sheathing?

I have read the Aug 21st post titled "Can Unvented Roof Assemblies Be Insulated with Fiberglass? http://www.greenbuildingadvisor.com/articles/dept/musings/can-unvented-r... I think the answer is "Yes, but...". And here is the but: You need to add the appropriate thickness of rigid foam to the exterior side of the OSB sheathing. I've read so many different roof profile scenarios...I know I ought to be able to figure this out...but I have a few questions...I'm hoping to get some confirmation of my lessons learned as a rookie here on GBA.

Asked By Inger Peters | Feb 10 16
5 Answers

"Green Building" and current (2012) code

Has current code 'caught up' to the point where "green building" today revolves around code compliance, HVAC design and choice of "green" interior materials?

Has "green building" gone mainstream with regards to the building envelope?

Asked By Chris M | Feb 12 16
16 Answers

Proper crawl space encapsulation and also radon mitigation questions

Hello, I own a 1968 cape cod style home in East Stroudsburg in the Poconos, PA (region 5). It has a full basement with 7' ceilings and concrete floor with probably little to no crushed stone underneath. At some point, there was a ditch cut out along 2 of the walls, with stone and probably a perforated pipe added, and concrete poured back except for a small channel along the block wall. This leads to a sump pit.

Adjacent to one of these 2 walls is a crawl space entrance where an addition was put in.

Asked By Ryan O'Rourke | Jan 26 16
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