Community: Building Code Questions

Q & A Instructions

[Click map to enlarge]

The GBAGreenBuildingAdvisor.com web site has a wealth of articles on a wide variety of construction topics. Before posting your question, you may want to check out the articles on this page: How To Do Everything. You just might discover an article there that provides the information you seek.

Please register for a free account or sign in to ask and answer green building questions.

If you want to post a question, the usual rules of courtesy apply:
1. Be nice.
2. If you can't be nice, be polite.
3. If you can't be nice or polite — well, please be brief.

To attach a photo or illustration: Under the box labeled “More explanation,” look for the words “File attachments.” Click that, and you should be able to attach a photo.

Thanks for joining the conversation!


3 Answers

Any experts in Title 24, Part 6 out there?

In replacing a wall and adding insulation (home was built in 1961 and currently has no wall insulation) I am also adding two small windows to this south-facing wall. Because I'm adding windows, I need to comply with either the prescriptive requirements of Title 24 or the performance requirements. Because I'm not adding conditioned space, I cannot demonstrate performance based only on the new space, but would have to demonstrate it on the whole house which is completely impossible without a gut remodel.

Asked By Domenico Perrella | Jun 11 17
5 Answers

How far apart must my HRV fresh air intake be from exhaust?

Just had an HRV installed and was expecting the fresh air intake to be on the front of my house because my furnace and water heater are vented on the corner of the side of my house. The installer used a 2 in one vent cover where the stale air and fresh air intake come out of one vent cover that is located 2 1/2 feet away from the first exhaust pipe. Is this safe or legal? How about if he adds snorkels to either the intake or the exhaust?

Asked By Lewberg | Jun 8 17
16 Answers

Shiplap in lieu of sheetrock - Questions regarding fire safety

I don't know if this is correct category to place this question in, but here's the deal:

Building a living unit in a section of a post-frame building. The exterior walls are constructed using the PERSIST method, with Grace Ice & Water shield covering the OSB, 1" foam on top of that. The stud bays will be insulated with poly-iso cut and cobbled, 3" thick.

Asked By John Peeper | Jun 2 17
13 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
2 Answers

Furnace cold air return requirement with HRV

New build in Ontario with Zehnder ComfoAir 550 HRV (home run system - not tied into furnace)

Does the furnace need traditional cold air returns in various rooms or can we just draw air back into the furnace directly from the basement (where the furnace is located)

The HRV is already moving air so not sure of the purpose of the cold air returns in this setup

Steve

Asked By Steve Babcock | May 12 17
1 Answer

I am going to put foundation drains around a detached garage. Where can I legally dump the water?

Is it legal to dump the water collected from the foundation drain into the gutters in the city streets?

Asked By Jschee | Apr 30 17
3 Answers

Permanent wood foundation (PWF) backfill height?

All the documentation I've found on PWF basements never shows insulation under the slab floor. The allowed back fill heights are always referenced to the bottom of the bottom plate of the wall which coincidentally is the bottom of the slab.

If under slab insulation is installed after the perimeter PWF walls are in place, the slab will be raised by the thickness of the insulation. With under-slab insulation is the backfill height the height above the slab bottom? or the bottom of the bottom plate?

Asked By Jerry Liebler | Apr 17 17
3 Answers

Deck footers

Good evening Everyone,

I'm attempting to build my first deck this spring. I've dug holes for footings and just passed my footing inspection.

The Deck code here in maryland dictates that holes are to be a minimum of 30" deep with an 18" wide by 10" deep concrete footing. Once you have that you can either use concrete piers to get your posts out of the ground or you can place the post right on the original footing.

Asked By Andy Pappas | Apr 17 17
1 Answer

15 minute thermal barrier

I have had 3" of Bayseal Closed cell foam sprayed into the exterior walls of my cabin. My intention was to apply 3/4" interlocking car siding over the insulation but our building inspector is suggesting it does not satisfy the 15 minute thermal barrier required. Does anyone have any information on this? I could use 1/2" drywall over the top or spray with a retardant but I'd rather not. If I use a retardant, any suggestions?

Let me know

Thanks

Asked By maggiebo | Apr 5 17
1 Answer

Exhaust vent outdoor opening size?

Okay, this is a nitpicking detail, but what does this part of the IRC mean?

R303.6 "Air exhaust and intake openings that terminate outdoors shall be protected with corrosion resistant screens, louvers, or grilles having an opening size of not less than 1/4" and a maximum opening size of 1/2", in any dimension."

Does this mean that the holes in an exhaust vent have to be smaller than an 1/2" circle? That doesn't line up with most of the vents that I've seen on the market, especially dryer vents.

--John

Asked By John Ranson | Mar 27 17
Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!