Finishing Basment - How to be Eco-Friendly?
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We'd like to finish the basement in our new (1.5 yrs) house and would prefer using sustainable/eco-friendly materials. Does anyone know of any (online or other) references for doing so?? We are familiar with low/no VOC paint and alternative flooring (cork, etc.). What we are not familiar with are possible insulation/beams that are more environmentally friendly than conventional materials.
One of the most important issues with finishing a basement is healthy air quality. The soil under a basement usually holds a constant temperature of ~50 deg north of the Mason Dixon in the US. This can become a problem in the summer, when this temp is lower than the air temp. Most basements are uninsulated, so the cold floor of the basement will force water to condense on the concrete. If you just cover up the concrete with wood or other organic materials, you are creating a prime mold growth environment.
This can be a big environmental problem (your very local environment!). But, your location has everything to do with this issue. A dry desert climate doesn't have the same issues as a humid temperate place... Once you get the big technical issues out of the way, you can move on to sustainable material selection.
Thanks for replying, Jesse.
We're outside of Philadelphia and it certainly does get quite humid here. It's interesting...we've been calling our basement *the wine cellar* because even in the dead of summer (and this summer has been a doozy) it's very comfortable down there. There's very little light coming in - we opted for a regular door as opposed to a slider and there's also a tiny window.
Any further information you could provide would be greatly appreciated. Thanks again.
OT: I checked out your web site. Beautiful homes. We honeymooned in Maine, near Acadia...what a gorgeous state.
VeryOT - checking out your links page I noticed Pitchfork. Was that your contribution or your partner's? Pitchfork reviews are a favorite at our house.
If it's an old basement, you need to design with the assumption that it'll get wet at some point.
Of the research I've done, the preferred method for insulating a basement is from the outside. Of course, with an old house, that's not so easy.
The method I've read that seems to hold the most logic these days is to use the pink EPS insulation from floor to ceiling, fully sealed (caulk top, bottom and seal joints with tape). This will be your (slightly) permeable vapor barrier. It should prevent humid air in the summer from reaching the cold wall and condensing. Then, fur with metal studs (2*2s) and finish with paperless sheetrock. I'd also leave a good gap at the floor in case of a flood.
For flooring, you likely want indoor-outdoor carpet.
Better than the EPS, is to use spray-on-foam. That will give you a complete seal.
Now, the catch is that all of the above is pretty much NOT code in a lot of areas. Around here, code dictates that we use a complete vapor barrier from rim joist to floor, then a complete VB across the entire floor. I don't like that.
One other alternative is the new Owens Corning system. Functionally, it's fairly ingenious...it uses fabric panels as your wall and fiberglass as the insulation. The concept being any air that gets back behind the wall can easily vent its way to the inside. The catch is that it's a REALLY ugly system.
We have an old house that i've long wanted to finish the basement on. We have 8' ceilings and a full fireplace, so it's a rather ideal basement, but it's an old one, and humid, and we may just put if off until we move. ;o)
Since you can't get insulation on the outside of your foundation (which is the right place for all new construction) you will have to make any changes to the interior. Your goal is to prevent water vapor for getting to the cold concrete where it will condense. Carefully taped rigid isulation will do this, but spray poly-foam (not water-based foam like Icenyne, it's too permeable) is the absolute best choice. Water can move through any spots you miss on the taped foam and once it is back there, it's not coming back out. But, careful installation like Incubus described works.
Spray polyurethane foam (like Corbond) will adhere directly to the brick / stone / concrete found in old basements, give you a tight air and water seal, and great R / inch. It's also the most expensive of all choices, but you get what you pay for. Exposed foam will require fireproofing. Burning foam is very toxic, so a layer of drywall will be necessary. The paperless drywall Incubus recommended is so mold cannot grow on the backside paper of standard drwywall.
Dow does make a rigid that can be exposed called Thermax ( http://www.dow.com/styrofoam/na/iso/thermax-ld.htm ), but you are planning on a finished basement.
Thanks for the kind comments on our work... Phil and I are both admitted music obsessives, hence the Pitchfork link.
And, the Gold Standards these days on technical information for residential construction are here:
Building America: (Download the climate guides on the right side of the page.)
http://www.eere.energy.gov/buildings/building_america/
Energy Environmental Building Association:
http://www.eeba.org/
http://www.eeba.org/technology/publications/default.htm
And if you buy ONE technical book this year, buy one of these (the appropriate book for your climate):
http://www.eeba.org/bookstore/books.asp?CatID=1
They cost $45, and are completely worth it.
Previously Erica Zbyszewski wrote:
We'd like to finish the basement in our new (1.5 yrs) house and would prefer using sustainable/eco-friendly materials. Does anyone know of any (online or other) references for doing so?? We are familiar with low/no VOC paint and alternative flooring (cork, etc.). What we are not familiar with are possible insulation/beams that are more environmentally friendly than conventional materials.
Erica...
You're biggest decisions are going to be insulation, floor covering, heating/cooling. You should look into Laminated Beams (uses less large trees), and non-formaldehyde insulation... you can also do a blow-in recycled cellulose. You want to make sure your basement is water tight from the 'outside'. As for the floor, I think the best option is to thrown down some flexible piping and run hot water through your floor... you'll save a TON on heating and it creates way better air quality than forced air. You can apply a layer of concrete over the tubes and finish that, or float a floor on top--- marmolum, sustainable wood, cork, or maybe someone in your area does earth floors (poured mud that's finished to almost a gloss... very cool)
Hey guys,
sorry to hijack this thread a little bit but I am building a home in Atlanta GA which will have a 1/2 basement. 6' below ground 2' above which will have some windows, I wanted to leave the walls and floor bear concrete because I like the look. Most of the replies have focused on condensation during summer for the OP with his location in PA and above the Mason Dixie line but should these same practices (insulating) be used for a home in Atlanta? or because of our climate and ground temp, is it not needed as much as is an option rather than a requirement?
Hey guys,
sorry to hijack this thread a little bit but I am building a home in Atlanta GA which will have a 1/2 basement. 6' below ground 2' above which will have some windows, I wanted to leave the walls and floor bear concrete because I like the look. Most of the replies have focused on condensation during summer for the OP with his location in PA and above the Mason Dixie line but should these same practices (insulating) be used for a home in Atlanta? or because of our climate and ground temp, is it not needed as much as is an option rather than a requirement?
Mike,
Basements, and moisture issues in general, are one of those issues that are very climate specific. In Atlanta, we absolutly do NOT want a vapor barrior on the inside of the walls. There are many different ways to insulate the walls. The best would be a continuous insulation, such as a foam board. You can sud up the walls off of the foam board. The band area is notoriusly difficult to insulate and air seal; spray foam is the best product to use there. For drywall, I recommend paperless drywall in below grade applications.If you get condensation on your concrete floors, it is because you have a humidity issue in your home. Hopefully, you have a complete vapor barrier and gravel bed beneath your new basement and a properly-installed drain beside your footing, so the moisture should not be coming in through the ground.
I have noticed from your posts that you are asking lots of good, technical questions. A great resource for the Southeast, located right in Atlanta, is Southface. Check them out.
Best regards,
Sydney
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