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1 Answer

What is the N.C. code requirement for R-value for roof and exterior walls? How many inches of closed-cell foam is it?

What would be recommended for the R-value and inches of closed-cell foam below living space and unheated garage space ?

Asked By Daniel Mckay | Sep 17 16
5 Answers

Return air location and height

I have a vintage 1985 tract home in San Diego County, Climate Zone 3B. I am planning for a kitchen remodel, drawing plans for a permit.

The return air is located in the kitchen, the kitchen is open to the main living room, so the room volume is not a problem. The return air is located in the far corner of the kitchen. The natural gas stove is about 8 ft away from the return air inlet. By the 2012 IRC the stove should be 10 ft away. I don't/can't plan to move it to get the distance.

Asked By Tim Rudolph | Sep 7 16
11 Answers

Residential frost-protected shallow foundation in central Mass.

We are planning to provide a monolithic pour frost-protected shallow foundation (FPSF) for a single story 1300 sq ft 2 bedroom home in central MA. Air Freezing Index is 2000. I have read through many different case studies, research papers, codes, etc and there is a bit of conflicting and locale-specific info so I am looking to see whether I understand what is required here. I am a newbie owner-builder. Any constructive criticism would be appreciated, but I don't want to foment any religious wars.

Asked By Kenneth Gartner | Sep 2 16
1 Answer

Venting bathroom through a flat roof

I am interested in learning if there is guidance or code that would cover venting a bath fan straight up through a flat roof. Our state's Weatherization Field Guide indicates that vent terminations shall not be allowed on flat roofs. My interpretation is that you are not allowed to place a fan vent termination on a flat roof. It also indicates that on sloped roof the termination should be elevated 18". There seems to be a lack of what is an acceptable venting configuration for a bath fan when you are forced to go through a flat roof.

Asked By Matthew Stewart | Aug 23 16
3 Answers

Venting a combined basement bathroom / laundry room into existing 4" vent / drain stack

I've had a few quotes for installing a new 4 piece combined basement bathroom / laundry room (dryer, shower sink toilet) as apart of getting our basement finished.

Currently the main 4" stack serves as a combined vent / drain for a 3 piece washroom (2nd story), and as a drain for a (1st story water closet - 2 piece, that is separately vented with a 2" vent through the roof)

Asked By Mike Tew | Aug 16 16
9 Answers

What fireblocking is required in double stud walls filled with dense pack cellulose?

Single floor over basement (unheated) residential, about 2400 sq ft. gable roof 18" cellulose ceiling insulation. Fiberboard sheathing XPS rain screen thin brick exterior. I would like to use OSB on the outer face of the inner wall. I'm hoping this will eliminate any required vertical fire blocking within the wall. plan on "capping" the top of the 2 wall assembly with OSB, can it be 7/16" or must it be 3/4? Wall insulation is dense pack cellulose.

Asked By Jerry Liebler | May 30 12
2 Answers

Closed-cell spray foam insulation under a sunporch

We installed 2 inches of spray foam closed cell insulation on the underside of a sun porch which is open on a sides underneath. My husband wants to store his riding lawn mower underneath which means he will have to drive it under the porch and start it up under the porch. I understand that this foam is highly flammable. Please advise if this is safe or what we can do to ensure safety of the storage of the riding mower. Thank you.

Denise P

Asked By Denise Phelps | Jul 27 16
3 Answers

Notched I-joist fix

We had a plumber notch our new home's engineered i-joist when installing a tub drain. We were furious but that is besides the point at this time. We are attempting to get it repaired.

Per the building inspector's recommendations, we contacted the joist company. They suggested cutting a 13" section of the damaged part of the joist and heading it off with smaller i-joist sections attached perpendicularly onto the two adjacent i-joists.

Asked By Kara English | Jun 22 16
11 Answers

Poly and Canadian building codes

This comes up quite frequently and I thought it might be useful to lay out what is actually required by the code. My description relies on the BC Building Code, but I am fairly confident it applies to all provinces that have based their codes on the NBC.

The code requires all building assemblies to include an air barrier and a vapour barrier.

The air barrier can consist of a variety of sheet or panels materials. It can be located anywhere in the assembly. That is the inner, intermediate or outside surfaces of the assembly (

Asked By Malcolm Taylor | Apr 4 16
9 Answers

Slab insulation - do I understand the code requirements?

Question about slab insulation. The current slab has zero insulation on each side. That was no issue until now because it always an unheated garage. The slab is just that, a slab. No footing, no drainage.

Living in zone 5A and using the table Martin gave me in another thread I conclude I need:
- R-10 on the edge. --> 2.38" EPS or XPS*
- R-30 on top of the floor indoor. --> 7.14" EPS or XPS*

*= I use R4.2 for both EPS and XPS because I will use reclaimed foam. From what's I've understood XPS outgasses and it's R-value drops to that of EPS over time.

Asked By Tony Tibbar | Jun 18 16
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