I’m looking for a good quality, static foundation vent screen and cover for new construction. I’m not real excited about the standard one that’s predominant on construction sites here in Southern CA- the 16 X 8 drawn steel louvers with screen welded behind.
The climate is mild, so we don’t need the kind that can be closed in the winter.
The exterior finish will be stucco in some places and veneer stone in others. Anyone have leads on a decent vent? Maybe aluminum? No wood though!
Thanks!
Jim
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Would you consider spending the money on a good quality vapor barrier over the soil and placing the insulation on the perimeter instead of in the floor? The results will surprise you. Improved indoor air quality, lower humidity levels in the home, warmer floors in winter, and lower utility bills are among the benefits. Learn more at http://www.buildingscience.com.
Ray, I think you also meant to say don't vent the crawlspace. As in, would you vent your basement?
It is rare for me to be to brief in my reply. Thank you for the clarification.
What works in one climate and set of conditions might not in another.Also, many building officials still require that vents be installed for crawls- at least they do in my area. Then we go ahead and condition them, loosely sealing the vents. (We don't want to presurize the crawl so that air from the crawl enters the living area.)
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Sojourners: Christians for Justice and Peace
I which climate is a vented crawl space a better idea than a sealed and conditioned "mini basement"?
>>In which climate is a vented crawl space a better idea than a sealed and conditioned "mini basement"?I don't know. Do you have expertise in all climates?One of the lessions one learns from the BS site is that a solution in one climate may be a problem in another.In my opinion, in my climate (NW Ohio) a year round conditioned crawlspace is better than vents; it's tough to say whether a vented crawl space is better when there is no central A/C, but I am inclined to say vented is better with no central A/C.
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Sojourners: Christians for Justice and Peace
I'm sorry if my tone was seemed rude. It didn't sound very nice on re-reading it.
It is never better to ventilate a crawlspace. BSC recommends conditioned crawlspaces in every climate from very cold to hot humid.
>>It is never better to ventilate a crawlspace. BSC recommends conditioned crawlspaces in every climate from very cold to hot humid.Conditioned, yes, but what about houses with no centrral A/C (northern climates)? The crawl won't be conditioned in the summer months, and those are the months that they tend to be more moist.There aren't many without central A/c, but they number isn't insignificant, either. I'd say maybe 10% of the houses I inspect don't have it or don't have ductwork in the crawl.
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Sojourners: Christians for Justice and Peace
If the floor is covered properly, moisture introduced from the soil will be miniscule. A small dehumidifier will take care of any moisture problems and the energy used will be a fraction of the savings in winter.
From the BSC website. "Venting crawl spaces made sense only when you had no air conditioning and no insulation and no crawl space walls."
I would agree that if there are no walls in the crawl space then venting is OK.
Here is a link for using this in a very cold climate. Aspen Colorado is the subject location. Air conditioning is not included in this design.
http://www.buildingscience.com/housesthatwork/verycold/aspen.htm
>>If the floor is covered properly, moisture introduced from the soil will be miniscule.<P>Usually, but but not always, at leats in my area. A lot of mositure can come in through the walls, but if you run the vapor barrier up the wall, you increase the chances of rising damp getting into the stuicture.I crawl through a couple of hundred crawl spaces a year. My comments are based on what I see.<P>From the BSC website. "Venting crawl spaces made sense only when you <B>had no air conditioning</B> and no insulation and no crawl space walls."<P>Exactly. Not all houses are conditioned year round.<P>When questions are posed here, we have to be careful not to assume too much.
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Sojourners: Christians for Justice and Peace
Lstiburek also said,"and no crawlspace walls". That means if you have crawlspace walls, don't vent the crawlspace. I sent the link to explain the use of this method in climates with long periods without air conditioning or none at all.
You are correct that encasing a foundation in a vapor barrier will increase the moisture content of the foundation. That does not mean that the frame will come in contact with this moisture. Rising damp is controlled by a vapor barrier, not ventilation. If there is no vapor barrier between the soil and the wood frame, the wood will collect moisture and potentially rot regardless of crawlspace ventilation. A vapor barrier must be placed between the foundation and the frame. This is illustrated in the link that I provided.
It is far better to keep the moisture out of your crawlspace all together. Thank you for the chance to respond.
FWIW, I was confusing this thread, aboout new construction, with a thread about old construction - obviously we have a lot more control over what to do with new than with old, and the types of variations I see are far more prevelant with old construction.
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Sojourners: Christians for Justice and Peace
Do not use aluminum for vents, they rot quickly the closer you are to the ocean.
As for wood, that's what they use for stucco mold. The biggest mistake on wood stucco mold is not pre-painting first. The wet stucco will swell up unpainted wood and then dry out to leave a crack between the wood and stucco.