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!


0 Answers

HVAC question

Hello!

We are building an energy efficient 2700 sq foot ranch, open concept. We live in Wisconsin and leave the windows closed year round due to allergies. So, the AC or Heat is normally running.

It has been suggested that I get an HRV. It has also been suggested that I get a whole house air purifier. Do I need both? Or maybe just and HRV and 4' media filter?

For the HRV, I have seen Lifebreath or Zehnder? Either one better, or other brands to consider?

My builder is not familiar with these specific types of products.

Thanks in advance for any help!

Jenny

In General questions | Asked By jabehling | Jul 21 17
2 Answers

What Mil vapor barrier will stop radon too?

I am going to install new plastic over the gravel in my crawl space. My primary goal is to reduce humidity. I was reading about radon and I might as well put down a plastic that will block both.

How thick of plastic do I need to stop humidity and radon?

In General questions | Asked By 99IdoDIY | Jul 21 17
3 Answers

Venting for multiple appliances

Hey GBA,

I wanted to reach out to the community for a thought experiment.

The home I am building will have the following :

High efficiency Gas furnace
High efficiency Gas water heater
ERV
Central vacuum

All of these require exterior intakes and exhausts.

The house is a row house, so the majority of the side walls are attached to another house. Thus, this only leaves one spot where I can place the multitude of vent pipes. (which is pretty much a small alcove at the rear between the two houses) see attached image.

In Mechanicals | Asked By Jamie B | Jul 21 17
6 Answers

Insulating floor before subfloor goes in.

I need to insulate the floor of Dear Old Mom's house in zone 4c to r-38 to earn enough green "credits." Conditioned crawl is not an option because of our hot radon potential. 22" crawl space makes working down there very difficult.
Would this work:
Cut 3" poly iso (R-19.6) to fit between the webs of the 9 ½" TJIs (19.2 o.c.) and rest them on the bottom flanges before the subfloor is installed (or stage the cut pieces in the crawl before the subfloor goes in). Later, cut access holes and blow cellulose to fill the remainder of joist bay.

In General questions | Asked By Mark Walker | Jul 21 17
6 Answers

Insulating balloon walls

High I am renovating a 1927 Dutch colonial with balloon wall construction. Th attic is finished but will be taken down to exposed walls and rafters. The exterior will be resided on the second level with Hardy board fibercement clapboards. The ground level is one layer of brick over wood sheathing. The roof will be replaced with an imitation slate product (DaVinci roof scrapes). All the windows were already replaced (Trim line) Aluminum clad wood thermopane windows. My question is about insulation. I will be cutting a ridge vent.

In Energy efficiency and durability | Asked By eh413 | Jul 20 17
6 Answers

EPS under siding

Hi all, I have a weekend cottage on a lake here in middle GA that was built in the mid-80’s that is in need of some serious TLC. One of the projects I’m planning on doing is to re-side the house with Hardiplank lap siding. The current siding is cedar lap on top of 1” foil faced Expanded Polystyrene (EPS). The corners are set with ½” plywood and ½” GP particle board for shear strength. Currently, there is no felt or house wrap between the sheathing and cedar siding. Due to 10 years of lack of maintenance and woodpeckers; the current cedar siding is in really bad shape.

In Energy efficiency and durability | Asked By Rudi Schmoll | Jul 21 17
6 Answers

Will R-70 cellulose sag ceiling drywall 24" o.c.?

My plans call for an R-70 ceiling of loose-pack cellulose in double-netted bays between trusses 24" o.c., with 5/8" Type X drywall holding it up as my air barrier. My installer says this will weigh about 2.55 lbs/sq/ft. Is this too much? Will it sag over time or pop screws? Do I need to use some special (expensive) low-sag drywall? I don't want to go to the expense and lost clearance of, e.g., an OSB layer above the drywall.

Anyone have experience with this?

Thanks.

Randy

In GBA Pro help | Asked By Randy Jorgen | Jul 16 17
1 Answer

Sand is becoming a scarce resource

Good Day,

There are a number of recent stories about the growing scarcity of sand and how this can impact construction, industrial and electronics industries (for example, see http://pulitzercenter.org/projects/deadly-global-war-sand). One example cited how China has used more sand for construction projects in the last few years than the US used on all of the 20th century.

In Green building techniques | Asked By Douglas Epperly | Jul 21 17
2 Answers

Build my own SIPs, or just frame it?

I am in the planning phase of building a second home and a shop on my property. I have access to as much insulation material as I need in 22" wide and various length (from 36" to 64") rigid foam insulation (door cut outs with the skins still on r 6.25 and 1 3/4" thick) for free!

In Green building techniques | Asked By Mathew Bean | Jul 20 17
4 Answers

Cost-effective option for improving cathedral roof insulation?

Hello all, Hello Martin.

I've read a number of GBA articles and posts regarding how to insulate cathedral ceilings, but I'm hoping for suggestions on the best way to improve our specific existing condition.

I'm in coastal Maine, zone 6a. Windy spot near a coastal river, not much shelter.

The 25 x 25 main wing of my 14 year-old house has a scissor-truss roof, with basic asphalt shingles in relatively good repair.

In Energy efficiency and durability | Asked By User-6889078 | Jul 21 17
Register for a free account and join the conversation


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