Crawl space ventilation on an old house.

[MidTen66]

This house has been renovated of good quality and appears to have been done right. There is one issue that stands out to me. There are no vents on the crawl space and it is a solid concrete foundation wall, no concrete blocks. The house was built in 1960. My question is: Is there a such thing as a "grandfather" clause for an older house such as this or....do I have them cut and install vents in the solid concrete foundation wall to adhere to ventilation guidelines / codes. My city codes man said for his requirements, he thinks it would be grandfathered and be okay. I just didn't know about FHA. Thanks for the feedback.

 

[Mountain Man]

FHA doesn't enforce building code, there is no way they could with so many different municipal regulations from county to county, city to city, state to state. So they pretty much leave it up to the appraiser to decide if it's a problem with safety, security, and soundness. Since you say it's been remodeled and done right, I assume you didn't notice any problems as of the day of inspection? So what's your problem?

 

[Mary Tiernan]

Just because a crawlspace has vents does not mean they are used properly.

Vents should be opened during warm weather and shut during cold weather. How many homeowners do you know that actually know this?

We had an addition built with a small crawlspace - the builder failed to install a vent. Our building inspector insisted one be installed - he told me, there's just too much worry over mold issues without vents.

But, if homeowners do not open the vents in the heat and close them in the cold, what's to prevent mold issues then?

I think I would insert a blurb about the lack of vents and what the building inspector said - leave it to the underwriter.

 

[Mr Rex]

I doubt this house has been sealed to the degree required in modern codes, but there is a movement towards "sealed crawlspaces" to eliminate some of the mold and indoor air quality problems as well as increased energy efficiency. This is allowed in most building codes:

http://apps1.eere.energy.gov/consumer/your_home/insulation_airsealing/index.cfm/mytopic=11480

 

[Mike Boyd]

"Sealed" foundation vents is a new one on me! In CA they are supposed to be functional year around. Where does the mositure go if the vents are sealed? Seems to me that especially in winter they should be open to STOP mold and dry rot.

 

[Mr Rex]

There is no moisture, it can't get into a sealed crawlspace, thats the beauty of it. Just got back from inspecting a 1912 house, they just had a sealed crawlspace system installed.

A sealed crawlspace consists of a heavy plastic material covering the ground, sealed at the seams, and turned up on the foundation walls all the way up to the top except for a small gap for termite inspection and similarly up the piers. The foundation walls are insulated on the inside, and there are usually 1 or 2 registers heating and cooling the crawlspace area creating a semi-conditioned space, so no floor insulation is required.The access door is also insulated and weatherstripped. Part of the reason ventilated crawlspaces do not work properly is that the typical house does not have true cross ventilation. With all of the typical offsets in todays "cut up" houses, along with a garage along one side, a porch on the front, perhaps a partial basementon one end etc, there often are many "dead air" areas under the house, and can lead to moisture problems. Having crawled under 100s of homes, I can say with certainty, a sealed crawlspace is superior and preferable to a conventional "ventilated" crawlspace.

 

[Mike Boyd]

There is no moisture, it can't get into a sealed crawlspace, thats the beauty of it. Just got back from inspecting a 1912 house, they just had a sealed crawlspace system installed.

A sealed crawlspace consists of a heavy plastic material covering the ground, sealed at the seams, and turned up on the foundation walls all the way up to the top except for a small gap for termite inspection and similarly up the piers. The foundation walls are insulated on the inside, and there are usually 1 or 2 registers heating and cooling the crawlspace area creating a semi-conditioned space, so no floor insulation is required.The access door is also insulated and weatherstripped. Part of the reason ventilated crawlspaces do not work properly is that the typical house does not have true cross ventilation. With all of the typical offsets in todays "cut up" houses, along with a garage along one side, a porch on the front, perhaps a partial basementon one end etc, there often are many "dead air" areas under the house, and can lead to moisture problems. Having crawled under 100s of homes, I can say with certainty, a sealed crawlspace is superior and preferable to a conventional "ventilated" crawlspace.

I see. The ground has also been sealed. I have never seen crawl space treated as such. Live and learn. Thanks, Rex.

 

[Mr Rex]

It has really come into favor with all the recent concerns about indoor air quality. I don't know about Cali, but here alot of the fan units for the heating and air conditioning are in the crawlspace. What do most crawlspaces smell like? Musty and moldy typically, and the duct work is usually leaky, sucking at least some of this crud into the house. I have done several "forensic" inspections for elderly folks complaining about breathing problems to find openings in the return ductwork, stopped up condensate drains etc in the unit under the house, creating really unhealthy air. After repairs, they have reported to me that their breathing obviously improved. One was a lady in her 80's, unit under the house, and the filter was slid in the side of the unit under the house. Obviously the little old lady wasn't crawling under the house to change the filter, and it had sucked the 2 year old filter into the unit, and was sucking the crawlspace air into the filter opening. The ladies son had a heart to heart with the HVAC installer, and offered to sue or allow him to install a filtered return inside the house. They installed a return and filter inside.

Since the sealed crawlspace is clean and dry, it eliminates these type problems as well.

 

[Daystar]

To seal or not to seal.

Done properly sealing up the vents actually makes for a much better house. For many years crawl space vents were considered to be
a good idea. Evidence now shows crawl space vents to
be a bad idea.

Vents act as a vacuum by actually sucking moisture into
our crawl space. Vents decrease our energy efficiency by
increasing our heating bills in the winter and increasing
out cooling bills in the summer.

Once the crawl space is sealed with a Seal Crawl Space
Encapsulation System the vents can be sealed. This will
stop any further moisture from entering the crawl space
through the vents.
For many years it was thought
that air would blow in a vent on one
side of a house and blow out of a
vent on the other side. We now
know this to be untrue.

It has now been proven that the air
that is sucked in through the vents
acts like a chimney.


Any air that is sucked through the crawl space vents or
from anywhere else on the lower levels rises up into the
interior of the house.

This chimney effect sucks the rising dirty air along with
everything that is airborne in the crawl space
environment with it. This dirty air is sucked right into
your interior living space. Into the very air you breathe . From......

http://www.sealcrawlspace.com/crawlspacevent.html