Q&A: A Forum for Green Building Experts and Beginners

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!


5 Answers

Rake flashing on a low slope roof.

Hello,

I am reading up on guidelines for rake/gable flashing for snaplock and most say to install the trim directly over the snaplock, with butyl tape underneath where the screws go. See here: http://www.westform.com/products.php?s1=residential&s2=prolok_12_16

Is this really the best way to install rake trim? Having exposed screws on a snaplock roof seems to defeat the purpose. With that being said, has anyone ran into any issues with this application?

I have also seen rake trim installed over z flashing, where there is no exposed screws.

Interested to hear your guys thoughts.

Asked By Tommy87 | Oct 23 17
8 Answers

Draining the Mega-Footing

I have gotten my engineering drawings on my new house(Zone 4, NC, steep slope). In places, the footing for the uphill concrete wall is over 13' wide! I have attached a representative cross section. How should I handle drainage? I plan to use a spray on membrane with a dimpled drain over that. How far down should that go past the footing/wall junction? Where should the drain-tile go, still at the edge of footing?

Asked By Kevin Spellman | Oct 19 17
2 Answers

Blown mineral wool retrofit interior walls?

I have a client who is interested in getting loose fill mineral wool blown into the attic and interior wall and ceiling cavities ('drill and fill') of her 1986 builder-grade house, primarily for insulation in the attic and sound attenuation (noise between rooms and from plumbing). Absolutely does not want to pull off crown moulding/base/trim to add another layer of gyp. board or isolation clips.

Asked By Chris B | Oct 23 17
8 Answers

Closed cell spray foam/cellulose combination

To all,

Background: 1500 Sq Ft. single level home, Northern Minnesota Zone 7, almost 10,000 HDD.

I am getting ready to insulate my double studded walls. The wall cavity including 2 2x4 24"OC studs separated by a 1" gap for a total cavity of 8". The ceiling has 2' energy heel trusses with 24+" of blown in cellulose

The original plan was to insulate the whole wall in cellulose, and at R3.9/inch the goal was 31 with no thermal bridging. Inside the cavity there was going to be a smart membrane (Intello Plus)

Asked By Steve Lenertz | Oct 21 17
3 Answers

Forced hot air control question

Hello,

I have a specific quesion on damper controls for multiple zones, but first the home background:

We are in the process of renovating our 3rd floor into a master bedroom. This is in addition to the existing 1,600 sq/ft house that has two existing zones: 1st floor (kitchen, bathroom, living room, dining room...7 vents total) and the 2nd floor (3 bedrooms and a bathroom...7 vents total).

Asked By Lostedge | Oct 23 17
4 Answers

Polyiso and loose-filled cellulose insulation in cathedral ceiling

I have a home built in the 1950s in Tennessee. The PO closed attic to make a large family room, bathroom, and full bath. No insulation has been installed in the knee walls or the slope of the ceiling. The space behind the knee walls is roughly another 800 sq. ft. of space, that I would like to turn into conditioned space.

Asked By LRSeries | Oct 19 17
7 Answers

AgePan with WRB

Our new house has AgePan on the exterior walls

It in the process of being covered with a WRB (Tyvek) prior to being strapped for siding

1. Do I require a WRB ?

2. Will the installed WRB case any problems with the AgeaAn / wall assembly.? Specifically I'm thinking about water vapor escape.

Steve

Asked By Steve Babcock | Oct 23 17
5 Answers

Vaulted ceiling, open attic

I have two vaulted ceilings that I am trying to work out how to insulate. I have read all the material here on insulating cathedrals. However these are essentially a variant on an unconditioned, vented flat attic. If the roof is 6/12, the ceiling is 3/12. Unfortunately while they are not a classic cathedral with only a stud's depth, they still have very little space between the ceiling joist and rafter, ruling out fluffy insulation. (The R-38 batts already brush the roof sheathing halfway down the slope) Dense pack, of course, I hear is a very bad idea due to moisture.

Asked By pshyvers | Oct 21 17
1 Answer

Poly or MemBrain?

In Maine, zone 6, zip code 04240. Finishing a large bonus room over a garage.
2x6 wall construction: vinyl siding, house wrap, osb, roxul; all in place.
Finishing the inside wall is the next step. T&G boards will be used, but have not yet decided if drywall will be installed first.

Need to decide on correct air barrier and/or vapor barrier. 6mil poly is the usual method, but with summertime AC in use, I am thinking this may not be the best choice. Will Certainteed MemBrain be a better choice for this application? Or should I just use the poly and not worry about it.

Asked By Tony Bouchard | Oct 22 17
5 Answers

Bonus Room Above Garage Insulation - SE Michigan

I know this has been talked about a lot but my bonus room above the garage is freezing in the winter especially the floor. The room has knee walls also. I am looking to get the room spray foamed and have had 2 guys come out with 2 different options and its a bit confusing. Options are below:

Current status - I ripped out the garage ceiling dry wall and pulled all the insulation down. There was differently a gap between insulation and the floor in spots and just not insulated good in my opinion.

Option 1

Asked By swdude12 | Oct 19 17
Register for a free account and join the conversation


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