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!


1 Answer

Does plywood flooring have to be removed before adding insulation?

My attic currently has a settled 8" of blow in insulation. I am adding more batts at an R-30 value. Previous owners installed plywood on joists for storage and nailed it every 6". Can the batts I'm addind be placed over plywood or must it be removed?

In General questions | Asked By Dan Dadario | Feb 6 16
25 Answers

Final advice on insulating a basement correctly

Hi I’ve read the great articles here on how to insulate the basement correctly - I just want to make sure I'm going to do the work right and I trust the folks at GBA

Overview

• Southern exposure home – south has 2x6 pt walls with a few windows and doors (basement level)
• North has an 8ft concrete wall that behaves like a huge cooler – it also has a 24inch 2x6 pt wall on top of that, so the basement ceiling height is 10ft.
• In the worst heat in summer 90 degrees + the basement is extremely cool with the windows closed – just like air conditioning

In GBA Pro help | Asked By Robert Metelsky | Aug 4 15
9 Answers

Roxul comfort board in basement?

I spoke to someone at the Roxul company the other day who recommended the following basement insulation. First, tyvek or similar against the concrete basement wall, then 1 1/4 " roxul comfort board for a thermal break, then a stud wall filled with roxul batts--- sheetrock. Do you see a real problem with water condensing on the concrete with the comfort board and tyvek there? Still seems like too much work but I am curious performance wise.

In Energy efficiency and durability | Asked By Nyle Phillips | Sep 27 12
6 Answers

Reducing noise transfer between rooms through ducts

In our current house which has all rigid metal ducts, noise transfers easily between rooms through the ductwork. For our new house, I want to make sure that the HRV ductwork does not have the same problem.

Flex is often maligned but it seems as though it could be useful in limited quantities. Based on what I read here, it seems that running a short section from the metal trunk to each room, while making sure the section is straight, pulled tight, and sized for the proper airflow (which probably makes this section upsized from the metal diameter), should not cause a problem.

In General questions | Asked By Nick Hall | Feb 2 16
32 Answers

Water heater decisions

In the process of building a new house and trying to decide on the best strategy for hot water heating.

We tried to be efficient with our floor plan design, and were able to clump the bathrooms and laundry room in one corner of the 2nd floor of our house. The guest bath is downstairs, almost directly underneath the baths upstairs. The only outlier is the kitchen and a half bath, which is on the other side of the house.

The house is all electric, and there are a couple of things I'm concerned about...

First

In Green building techniques | Asked By Clay Whitenack | Feb 1 16
1 Answer

Minisplit Location Feasibility

Hello,
I'm looking at possibly installing minisplits in my home to replace the hydronic floor heat and forced air system without having to remove my slab to insulate the current floor heat system. The current forced air is the R4 (I believe) pre-insulated flexible ducts in a vented attic. I figure the minisplits could greatly increase my heating and cooling efficiency.

In Mechanicals | Asked By Mike M | Feb 6 16
1 Answer

Hydronic Radiant Floor Heating Under Thick Slab

Hi All,
I have a timber framed house, the sub-floor of which was built with thick 2-in pine tongue and groove boards. This subfloor is also functioning as the main floor of the house in living room area, there is nothing on top of them. These boards have tons of character and I would like to keep them as the main floor.

I am renovating the down stairs and will be converting my hydronic base board heat to radiant floor in the kitchen and bathroom where I can run the pipes over the existing subfloor (plywood in these areas not the tongue and groove pine).

In Energy efficiency and durability | Asked By Ryan Wynne | Feb 4 16
9 Answers

Capillary Break Needed?

I am about to start installing 1” of Roxul Drainboard on the exterior of my foundation and have plans to bring it up to my siding. The siding sticks out 1” and the Roxul is 1” thick, do I need to leave a gap between the Roxul and Vinyl siding or add some sort of break between them to keep the Roxul from wicking up water to the siding with the potential to hit the sheathing?

Thanks

In General questions | Asked By Chris King | Feb 4 16
4 Answers

Heat pump sizing

Hello,

In General questions | Asked By matthias paustian | Feb 4 16
6 Answers

Radiant Barrier House Wrap- Bug Screen at base of Air Gap?

Per the manufacture specs --- going to have a 1/2 air gap between the wall sheathing wrapped in perforated radiant barrier and the finish wall.

Looking for a durable screen to install at the base of the wall between the finish wall and the sheathing to let the air and moisture escape and no bugs to enter?

It seems Cor-a-vent has a fiber based screen that sounds like it wont last?

Any advice.

In Energy efficiency and durability | Asked By Brent Shafer | Feb 5 16
Register for a free account and join the conversation


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