Community: GBA Pro help

[Click map to enlarge]

drawing of climate zone map.gif

Advice can depend on climate -- Please specify in your question.

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

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!

Ask a Question >
2 Answers
Help deciding which Mini-Split HVAC to buy

I'm following advice from a previous question I posted here and planning to install a mini-split in my garage apartment. Various sources and calculations indicate an 18,000btu unit is optimal. I'm thinking of purchasing one online, doing some of the less technical work, and having my AC technician do the final hook ups, etc. I have a few questions inhibiting progress.

Asked By Dorothy Prowell | May 20 12
9 Answers
Waterproofing concrete slab

I have a large V-deck which four inches of concrete has been poured. On top of the concrete we are planning of pouring four inches of color concrete to finish the deck. Our concrete contractor wants us to put a waterproof barrier between the two concrete slabs and it has been recommended to use 60 mil epdm membrane. This seems like overkill and I was wondering if a membrane is really needed or if there is are any other waterproofing applications which will work. Your recommendations are appreciated.

Asked By dennis levine | May 18 12
3 Answers
Indoor air quality

Hello GBA!

We are looking for solutions to help with the indoor air quality of our home. We live in the Minneapolis, MN area and have switched our home from forced air to a hydronic system. This was done to enable us to remodel our home to better suit our needs. Due to this change and the tighter envelope of our house, we are experiencing the typical condensation on our windows during the winter. Are there any ideas out there that may help us control the air quality inside our home?

Thanks for the help!

Mark and Melani

Asked By Mark Bowser | May 12 12
7 Answers
Zone 5 - Vapor Retarder on ceiling of indoor swimming pool

I an an insulator and a little confused on the subject of vapor retarders for ceilings. Normally we do not put a vapor retarder on the ceiling for Zone 5. But we are doing a job for someone that is enclosing their swimming pool and I am concerned that with that much humidity it might be necessary. They are installing an air-exchange unit of some kind but I do not have any details on that at this time. If this question has already been answered, can you please direct me to that thread?

Thank you

Asked By Lisa Goodman | Feb 6 12
3 Answers
What is the smartest way to insulate a finished attic?

Hi. I am a newby on this site and am looking for advice on how to correctly insulate the living space in my attic.

I believe in a vented roof so I vented the rafter bays with 1" Dow Tuff R rigid insulation spaced 2" off the underside of the roof sheathing. It is sealed all the way down to the floor and it ends about 6 inches above the collar ties. I sealed all the edges with foam and I taped all the seams.

The rafters are 2x10 and the collar ties are 2x8. I live in northern New Jersey in IECC zone 4. The rigid insulation is R6.5.

Asked By Randy Aubrecht | May 7 12
4 Answers
How is that a material can be both airtight and vapor permeable?

Can anyone point me to an answer that explains the physics? Obviously to be vapor permeable a material must have penetrations that are bigger than vapor molecules; why doesn’t air, driven by an air pressure differential, flow through the same holes? I’ve heard it said that the pores are big enough for H2O molecules but too small for O2; is that it? Or is it simply that the rate of air leakage is too low to matter given the grosser methods used to measure air leakage compared to vapor diffusion?

Asked By Hayden Robinson | May 4 12
14 Answers
Airstream renovation

Hi, I'm helping someone renovate an airstream, which is to be a non moveable, room near their house. The house is in upstate NY, on the border between zone 5a and 6a. It's completely gutted, so it's just an aluminum can at this point. The plan is insulate it with closed cell foam, 1-1 1/2" on walls and ceiling, 3" in floor. That's all the insulation the frame will allow, unless some more extensive modifications are done. It's going to be heated in winter with a small propane heater, designed for boats.

Asked By Mark Zachelmayer | May 1 12
5 Answers
What works best under a foam exterior?

I've watched the videos on installing foam board on the exterior of a house but what does the foam sit on at the the sill plate? I'm leaning towards a metal drip edge but others use Azeck board.

The reason I ask is that the videos address the windows well but what about the doors. We are not planning on putting bucks at the rough openings of the doors, just the windows. Since the door frame will be hanging out over the foam I just wanted to know how to support it if I use a metal drip edge like in the videos.

I also need some advice on a bug screen, what should I use?

Asked By john bell | Apr 30 12
2 Answers
Do I need to install an underlayment?

Do I still need an underlayment on a first-floor hardwood floor if I have a conditioned crawlspace with a vapor barrier on grade?

Asked By Matt Black | Apr 26 12
4 Answers
How can I turn my pseudo vented roof into a true unvented roof, with cathedral ceilings?

We are living in a new house with a low pitch 1.5:12 metal split shed roof and cathedral ceilings. There was a misunderstanding when the house was built and no ventilation was framed in under the roof. We found out when we had condensation issues dripping on us over the winter....So now we want to go back to the architect's original intention and turn it into an unvented roof. In order to avoid the huge mess of taking the drywall ceilings out and spraying foam in from below, we want to know if we can do it effectively from above?

Asked By dena platis | Apr 24 12
Register for a free account and join the conversation


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