Basement framing and insulating?
I recently framed out a large section of my basement. Half of the framing was existing 2×3s, most likely 20-30 years old or more. The framing in the very corner of the basement, which was I assume had moisture over the past many years, the wood smells pretty bad.
It’s an odd smell, like something sour or rotten. The wood appears to be strong and no mold present, it just smells bad, especially on humid days. I think what I will do is rip out the affected studs and replace with new, but I’m curious of what that smell could be?
Next - for the walls that are 2" off of the concrete walls, I plan to you the polypropylene board insulation.
I’ve read in a few different postings that some guys cut the boards to fit perfectly between the 16" on-center studs and either caulk them in or use that foam stuff spray to hold it in place.
I assume I want to use at least 3/4" between each stud. Any thoughts on this?
Also I’ve checked Lowes and I can’t seem to find what I am looking for. They only appear to have either very thin foam boards or 12" wide pre-cut sections. I guess I need to buy 4×8 sheets of this stuff somewhere and cut it down myself?
Quick note - I have no immediate moisture problems in my basement, no puddling water to be found.
I’m sure there is vapor coming thru the walls, and I’ve painted the walls with some sealer for the heck of it. But nothing too major that I’m going to worry too much over. But that’s why I plan to use the foam instead of anything else.
Thanks in advance for any advice.
The U.S. Department of Energy recommend that:
1 - Extruded (not expanded) polystyrene board be applied directly against the basement wall (no framing or studs needed) and that the gaps between boards be sealed with mastic tape. The idea here is to avoid the use of wood studs directly against the basement walls, because wood soaks moisture and favors mold growth.
The smell that you detected on those studs is mold. Mold smells before it can be seen and way before it starts to actually rot the wood. And it spreads quickly too.
That is why the Department of Energy recommends that they be kept away from the basement walls. In their approach, the insulation boards, sealed in the joints with mastic tape act as a vapor barrier.
After lining the walls with insulation, furry strips can be placed on top of the boards to attach the drywall.
I am adding here a link to two of their issued PDFs on the matter I wouls strongly suggest you look into if you want your basement finishing job to last.
Two more things to consider:
- Keep in mind that the these measures only deal with outside ground moisture that seeps through basement walls. Below grade structures are prone to moisture from more than one source, one of which being condensation. Consider installing a good, energy star rated basement dehumidifier.
- Drywall and wood studs will also not withstand a basement flood or even a plumbing accident.
An alternative to these would be using finished, cement-core, insulated basement wall panels. They are 100% waterproof, non-absorbent all-in-one solutions that won’t get ruined if your basement is under water. They also have the advantage of being removable to access wires and plumbing or inspect the walls, and the cement core gives you walls that are sturdier than drywall, where you can hang book shelves and big screen TVs without needing to look for studs.
I think you will need a vapor barrier on the outside walls and nail the foam panels like you would drywall. and you are right in replacing the 2×4 that has a oder I don’t know what it could be. Good Luck
References :
Depending on how saving the existing framing would save you in time and money….you should consider using an oil based primer (zinser / kilz) to seal them to block the odor. If they are structurally sound, then you could save yourself some work. The OIL based primers block stains AND odor. I use them for sealing sooted framing that is still structurally sound after a fire when I restore homes. Just a suggestion.
References :
Restoration Contractor
So you sealed the walls, that’s enough if they are sealed. Your studs in the corner were molded at one time and someone applied a sealer, yes replace them. Yes get 4 x 8 sheets, and use liquid nail.
Get advice on the R value, and what you are willing to pay. I would allow air movement to this space but not continuous ventilation. Negative pressure should be avoided. I think anymore advice beyond what I have offered, should be researched thoroughly.
References :
was in construction for 29 years.
The U.S. Department of Energy recommend that:
1 - Extruded (not expanded) polystyrene board be applied directly against the basement wall (no framing or studs needed) and that the gaps between boards be sealed with mastic tape. The idea here is to avoid the use of wood studs directly against the basement walls, because wood soaks moisture and favors mold growth.
The smell that you detected on those studs is mold. Mold smells before it can be seen and way before it starts to actually rot the wood. And it spreads quickly too.
That is why the Department of Energy recommends that they be kept away from the basement walls. In their approach, the insulation boards, sealed in the joints with mastic tape act as a vapor barrier.
After lining the walls with insulation, furry strips can be placed on top of the boards to attach the drywall.
I am adding here a link to two of their issued PDFs on the matter I wouls strongly suggest you look into if you want your basement finishing job to last.
Two more things to consider:
- Keep in mind that the these measures only deal with outside ground moisture that seeps through basement walls. Below grade structures are prone to moisture from more than one source, one of which being condensation. Consider installing a good, energy star rated basement dehumidifier.
- Drywall and wood studs will also not withstand a basement flood or even a plumbing accident.
An alternative to these would be using finished, cement-core, insulated basement wall panels. They are 100% waterproof, non-absorbent all-in-one solutions that won’t get ruined if your basement is under water. They also have the advantage of being removable to access wires and plumbing or inspect the walls, and the cement core gives you walls that are sturdier than drywall, where you can hang book shelves and big screen TVs without needing to look for studs.
References :
http://www.eere.energy.gov/buildings/building_america/pdfs/db/35017.pdf
http://knol.google.com/k/cynthia-freeney/basement-walls-do-it-once-do-it-right/2zysz04ujf01c/5#