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Does green building seem to be at odds with the code?

Please encourage your building inspector to come here and participate in this Code Q&A; in the meantime, jump in with your experiences -- both positive and negative.

5 Answers

Zone 4B - 2012 IBC and SHGC

The new 2012 IBC adoption in my future building area will mandate that windows can only have a maximum of 0.40 SHGC, including the south facing windows. I am trying to achieve a Passive House design but the low SHGC mandate makes it more difficult. I am going with Intus uPVC triple pane windows. Originally I was going to go with the 0.49 SHGC for the south elevation but now I have to go with the 0.37 SHGC. The building department will NOT budge on this factor and will not allow any windows > 0.40 SHGC.

Asked By Peter L | Sep 13 14
4 Answers

Vapor retarders for double stud cellulose-filled wall assemblies

Following up on last month's blog about building codes, am I correct that the code allows interior vapor retarding with latex paint on sheet rock? Also, does the vapor permeability of ZIP sheathing prevent inner wall condensation without the use of exterior foam?

Asked By Michael Roland | Aug 7 14
1 Answer

Combustion air requirements

Without getting into the other air intake possibilities...code requires that the outside air intake ducts be covered with no less than a 1/4" screen. My concern is that there are a lot of bugs, mold spores, etc. that are much smaller. There's no way to fit this with a filter?

More details:

Asked By Jim Johnston | Aug 1 14
4 Answers

Can you run the gas line against the flue pipe on a heater?

I had a new central air installed, and the gas line is against the flue on the heater.

Asked By MARK ALATORRE | Jul 23 14
3 Answers

In an unsinsulated service cavity (created by running horizontal 2x lumber) is fire blocking required? Or is it a good idea?

My proposed wall assembly from outside to inside:

1. Ribbed steel siding
2. 3/6" fanfold battens to create air space
3. 1/2" cdx
4. 2x8 stud cavity filled with wet spray cellulose
5. 2" eps nailed to studs (interior uninterrupted rigid foam)
6. 1.5" uninsulated service cavity (created with horizontal 2x4s)
7. 3/8" acx plywood (interior wall finish)

The building is a heated workshop with some pretty high electrical needs for the machinery. Since it's not a residence, I could probably forgo the fire blocking.

Asked By Rick Van Handel | Jul 14 14
19 Answers

Insulating between studs with polyiso scrap?

Wasn't sure what category to put this in, but my situation is that I had most of the exterior of my house covered with foil-faced polyiso insulation (Rmax Thermasheath-3). The walls between the living space (bathroom, laundry, pantry, hallway) and garage did not get this treatment, but they still need insulation. I ended up with some scrap due to normal wastage, as well as some extra sheets (since we had to buy some of it by the pallet). My plan has been to cut it to fit in the stud bays and foam around to hold it in place/air-seal.

Asked By Scott Heeschen | Dec 30 10
4 Answers

HVAC HRV sized correctly for my home?

A HVAC contractor installed a Venmar HEPA 3100 HRV in my new construction home. I was wondering if it is sized correctly for my house and meets the international building code and international mechanical code requirements. HVAC Work began in 2011 but venmar was installed late 2013.

My house is:

4846 square feet with a 486 square foot attached 2 car garage. Total sq ft: 5332.
Bedrooms: 5, Bathrooms: 6..

I was ordering a new filter and noticed it was discontinued and said:

for homes up to 3100 square feet ***
*** for new construction refer to building codes.

Asked By Sam Miller | Jul 4 14
2 Answers

Cedar poles for verandas

We live in New Zealand. We want to use our home-grown cedar poles for the veranda but cannot get council approval.

We have some cedar whole tree poles. They include soft outer wood but are 25+ years old and have a minimum of 80 mm heart. They are protected from the weather by the verandas, but because I grew them on my property and they don't carry a durability and strength certification, the building inspector will not sign them off.


Asked By Pete Davies | Jul 1 14
4 Answers

Spray foam ignition barrier

When one applies spray foam on the rim joist of above an unfinished basement is an "ignition barrier required? Will a 3 1/2" bat of mineral wool meet the requirement?

Asked By Jerry Liebler | Jun 11 14
12 Answers

Sheathing under metal roof

I Goggled this question, what lead me to this website. I read about this same topic here, I believe it was from 2012, however, the same question but for a house not a shed.

Asked By Philip Taylor | May 29 14
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