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Let Me Take You Down: Crawl Space Horrors Pt 3

By Steven L. Smith

Home Inspector with King of the House Home Inspection, Inc. Home Inspector Lic #207

July 01, 2007 05:59 PM

Yesterday, when I posted part two of Crawl Space Horrors, a realtor mentioned that she could not understand how people could be so oblivious to what is happening under their home. With a few exceptions, I find that people have no clue. Now, if the toilet drain was never hooked up they might figure that out -- then again don't count on it. I have the photos to prove that point but will not be sharing them. This inspection below is from more than a year ago. I saw clues that something was going on, but I do not think the people knew what was going on even though they were working around a problem. Virtually every room had a dehumidifier running. There was one in each bedroom, the living room and the den. They were fancy devices that actually vent outdoors with a vacuum cleaner type hose that routes to the window. Most of the windows were open to accomodate these devices. I asked the son of the seller why they had so many units. He said they just liked to condition the air.

When I got in the crawl space, I realized what was going on. The people caught on that the house was too damp inside, but they had no idea why. So, instead of doing some detective work, they tried to dehumidify the air. The first picture was my first view. When I opened the door of the crawl space, I saw a sheen to the insulation. I touched it and it was like a wet bath towel. As I looked deeper inside, it was like viewing something from a haunted house. The insulation had collapsed. The crawl space vents were blocked or below grade so all of the moisture present was going up into the insulation and finally up into the house. You ask: Why was there moisture? Well, there was a plumbing leak -- I believe a tub -- and it was completely filling one half of the crawl space with about 3" of water every morning. It would have filled the other half too, but there was a low concrete wall down the center that acted as a barrier. The wood joists and beams had turned a black fungal color and it was rotten in many areas.

I changed my procedures a bit after this one. When I see a house, anymore, that has blocked crawl space vents and other conducive conditions, I take a reading inside with a relative humidity gauge. I have found that, usually, I know from that reading just how wet and icky the crawl space might be. This real estate deal, by the way, did not close. Too bad really. The sellers were nice people and had no idea, despite the clues they missed along the way, that the house had this leak. The problem was, the longterm leak was no longer the problem -- the whole crawl space had become the issue. Most people just do not go under there, period!

First view, wet, collapsed insulation

3" of water

The state of the lumber

Thanks for boating with me,

Steven L. Smith,

Bellingham WA home inspector

www.kingofthehouse.com

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James Quarello

JRV Home Inspection Services, LLC - Wallingford, CT

Connecticut Home Inspector

Steven,

Nasty looking crawl! I want to comment on what you called a conducive condition. Vents that are blocked. Actually not venting a crawl space has been discovered to be better than venting. The building codes do require venting, but there is a push to change the code.

Crawl space vents in fact do not cross ventilate and dry the space. Air moves by convection, warm to cold. In the warm months, when the air holds more moisture, the warm air is drawn to the cool air in the crawl space. When warm moisture laden air comes in contact with cool air what occurs? Condensation.

What you discovered in your example had nothing or little to do with venting. When you have a pool in your crawl space no amount of venting is going to help. They need a plumber and a pump!

Other conditions will also contribute to moisture such as a dirt floor. I can tell you from my experience that unvented crawl spaces are not generally wet or damp. If they are there is a cause for the moisture such as a foundation or plumbing leak. I believe in the future we will see new homes built without crawl space vents.

Jul 01, 2007 11:46 PM

Paul Moye

Benchmark Realty - Franklin, TN

Broker, GRI, SRES

Cross ventilation only works if the homeowner actually does it correctly and if the floor has a vapor barrier and rock.

Older dirt crawl spaces are always going to be wet and a place to avaoid like in Silence of the Lambs

"It rubs the lotion on its skin and puts it in the bucket again"

Jul 02, 2007 12:45 AM

James Quarello

JRV Home Inspection Services, LLC - Wallingford, CT

Connecticut Home Inspector

Paul,

What? You must not of read what I wrote. Cross ventilation does not occur due to convection. If the floor has a vapor barrier, which it should, or rock the amount of moisture from the ground is greatly reduced. The vents have nothing to do with the floor composition and moisture emanating from that source.

Jul 02, 2007 12:53 AM

Steven L. Smith

King of the House Home Inspection, Inc. - Bellingham, WA

Bellingham WA Home Inspector

James,

That is certainly true that, with this quantity of water, nothing would get rid of it other than fixing the leak. That is fixing the cause, as I referred to, and not treating the symptoms. As far as conducive conditions, like blocked vents, these are mandated by the state of Washington Dept of Agriculture and, by state law, we have to call blocked vents or lack of ventilation as conducive conditions. It is not bldg codes, it is the state law. The only exceptions: Seen in maybe 1 of every 200 houses, is crawl spaces that are by design heated and not vented. That is, they are on a slab, vapor barrier under that and they are insulated on the interior and have a slight heat source, like a duct from a furnace. If they are not done right, the rim joist is often soaking with water behind the insulation.

I can tell you from experience in this region that, when I see crawl spaces with no vents in older homes, almost every single time they have serious anobiid beetle infestations. I do not know if you have that pest where you live. It tends to be in maritime climates, by the coast. It is probably the worst insect WDO around here and infests damp crawl spaces with poor ventilation. I could post photo after photo of unvented crawl spaces, some with no other visible conducive conditions, and they have been destroyed by anobiiid beetles. They have the vapor barrier which helps. But in unvented crawl spaces in this climate, even if other conducive conditions are eliminated (gutters drained away from house, no wood to earth, no water leaks) anobiids are found time and time again. Despite any personal views, in this state, if a home has foundation vents, and they are blocked, to not call that as a conducive condition, and to also recommend a correction, violates state law and would put the inspector at risk of a fine or losing his license. Homes with crawl spaces must be ventilated!

Now I know that, in the last few years,builders, inspectors and others, debate crawl vents vs no vents. I know if you do internet research you can find arguments both ways. My thought, based on seeing many crawl spaces, is that with a properly designed modern heated crawl space, much like a low basement, that might be better. That has been done here for such a short time that the jury is still out. But to take a conventional crawl space in our climate, and to block the existing vents, is an invitation for an anobiid infestation. It takes about 7 years to see it, maybe 10 but once it is going, what a mess. The larvae stays in that wood eating if the moisture content is 13% or more. In this climate, without vents or the heated crawl space, the wood will be above 13%, usually just below 20%. When I write of wood destroying organisms, my take is slanted to this state as it is where I work and negotiate the laws. Some of the more general information is not. Based on what I have seen, I cannot imagine ever telling someone to put covers on their existing vents.

Jul 02, 2007 02:23 AM

James Quarello

JRV Home Inspection Services, LLC - Wallingford, CT

Connecticut Home Inspector

Steven,

I am from CT and did realize you are from WA and that part of your State is considered marine climate. Ct is a moderate zone climate. Much different from yours. As you said you have to follow the rules of your state and the conditions of your region. We don't have anobiidbeetles here in Ct. We do have something called powder post beetle which like moist areas. But the moisture must be excessive, 13% is not extremely moist. So I can understand how that must be a real nightmare for homeowners and inspectors.

Not venting crawl spaces here in Ct in my experience is not a problem. I would definitely side with the no venting argument. But as you pointed out this practice certainly sounds regional specific.

By the way are WA inspectors licensed or regulated? We have licensing in CT. Your answer sounded like you are held accountable similar to a building official.

Jul 02, 2007 02:49 AM

Steven L. Smith

King of the House Home Inspection, Inc. - Bellingham, WA

Bellingham WA Home Inspector

James, Good thoughtful reply. We are kind of weird birds in this state as far as licensing. Those of us who are serious, are state WDO licensed to legally inspect homes as part of a real estate transaction. That does not mean that some people do not try to get around it. The WDO rules require a test, mandatory insurance and is a well run program with some teeth. The rub is, if a person wants to be a "home inspector" he or she can get by with looking at the furnace, call height differences on the rise at steps, and that kind of thing but cannot legally mention a leaky faucet or a blocked downspout. Basically they cannot say anything about the crawl space or the roof, at least if there are problems. Some try to get around it by doing a home inspection, and then sub out the WDO. But, anyone serious about doing the job, gets the WDO license -- who wants to pay out a couple hundred bucks of every inspection to a sub? The answer -- only those dabbling at the game but not serious about it.

I think, if we did not have anobiid, the blocked vents might work here. It is one nasty pest and, as you said, it requires less moisture than PP beetle and it prefers the soft woods of the crawl spaces so it will operate down there for years, with people having no clue it is around

Jul 02, 2007 03:07 AM

David Helm

Helm Home Inspections - Bellingham, WA

Bellingham, Wa. Licensed Home Insp

Just to jump in here about crawl spaces. A conditioned crawl, which is fairly new here can and should be unvented. Any non conditioned crawl must be vented. Convection is not the method of venting here. In spite of the perception of rain all the time, the relative humidity in Washingto is considerably lower, in general, than that in Connecticut. The air coming in the vents is virtually always dryer than the crawl space air. Inadequate or closed vents, by restricting air flow, allow the humidity level in the crawl to dramatically increase, increasing the moisture level in the wood over time; hence, conducive conditions. The 13% threshhold for Anobiids, being relatively low, is easily reached. . .and since Anobiids do their dirty work on softwoods (framing lumber, primarily Douglas Fir), the damage is structural and can be devastating.

Jul 02, 2007 03:56 AM

Marlene Bridges

Village Real Estate Services, Inc. - Laguna Hills, CA

Laguna Homes|Laguna Condos|Laguna Real Estate

Steven - I always thought that green slicker was for the Washington weather. NOw I see it's for going under houses. Maybe you might want to consider a wetsuit! Seriously, how far do you go under these houses? Once you start to get wet do you just stop there? Yucko!

Jul 02, 2007 04:24 AM

James Quarello

JRV Home Inspection Services, LLC - Wallingford, CT

Connecticut Home Inspector

David,

Just to clarify, convection is not a method of venting. It is a natural physical law. Warm air moves to cold air. It is one of the three principles of thermo dynamics.

What I am saying is that when the air outside is warmer than the air in the crawl space the warm air will be naturally drawn to the cooler crawl space air. The warmer air contains moisture which will condense when it cools in the crawl space. The RH of the air in the crawl space has little to do with the RH of the outside air. The air in the crawl can only hold as much moisture as its temperature will allow. The warmer the air the more moisture it can hold. This of course does not even begin to consider air pressures and how they also affect air movement in a home.

As far as climate in CT as compared to WA you are lets say two thirds correct. The coastal area of WA, about one third of the state, is considered marine climate. The other two thirds is considered moderate and thus similar to CT.

Jul 02, 2007 06:11 AM

Steven L. Smith

King of the House Home Inspection, Inc. - Bellingham, WA

Bellingham WA Home Inspector

Regardless of the theories of ventilation and what is best, and dealing only with my region of the state, I have seen enough to know that vents had better be open. I think I can best get my point across in photos. Photo one and two shows what I see 90% of the time on a home 25-30 years or older when I find crawl space vents that are blocked.

The lower photo, a home of comparable age, that has had open vents. I think other WA inspectors, at least this side of the mountains, have similar experiences.