The Cat House & Home Inspection Protocol

 Just walking around a home–looking at it from a distance–I can often tell what might be in store for me on the interior.  Home inspectors will usually take this “macro-view” of the home prior to getting up close and personal with the “micro-view.”  It is a very important part of the home inspection protocol to utilize both of these views of the home–and all the spaces in between.

Crawl spaces

At a recent inspection, as I headed around the back side of the home, I took the following picture.

Cats in the crawl space

I suspected the home probably had a crawl space even though I was told it did not–supposedly built on a slab.

As I saw Kitty-Kitty sticking his head out of the crawl space hatch I knew what this meant–there was indeed a crawl space as I suspected.

Well it could have also meant that this was just the access well and that there was a door behind Kitty-Kitty and he was just hanging out in the access well.

But I knew what this meant.  There was in  fact no cover at all and the crawl space was where Kitty-Kitty lived.  The best I could hope for was that Kitty-Kitty had not turned the crawl space into a latrine and that he would be amenable to my checking out his digs.

As it turned out, not only was he amendable–so was his partner.

cats in the crawl space

Neither one even minded me snapping a few pictures–in fact one never even seemed to wake up.

I was also grateful that their digs was still a crawl space–instead of a litter-box.

Crawl spaces are perfect environments for cats.  They are dark, there is a high likelihood of mobile food, and they can do what cats do.

By Charles Buell, Real Estate Inspections in Seattle

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Are you NUTS? Why would I want to vent my crawl space in the winter?

I have been around and around with clients enough to know that there are many people that seem to think that venting crawl spaces in the winter is a bad idea–especially in the wet NW where outdoor winter humidity can be close to 100% for much of the time.

floodedcrawl3Why would anyone in their right mind want to draw all that wet air into the crawl space?  Sounds like a problem waiting to happen, doesn’t it?

To get to the answer however, we have to actually look at the science of humidity and how important to our homes (as well as to our answering the question) that we understand that humidity has a critical relationship with “temperature.”

The truth, as counter-intuitive as it may seem, is that we can actually “lower” the moisture in a wet crawl space by bringing in this 100% moist air.

Some of you will be absolutely certain that I am celebrating WA State’s new Mary Jane law–but I assure you that, not only do I not inhale, but that I am not smoking anything funny at all.

Again the key is “temperature.”

Air at 40 degrees F cannot hold as much moisture as 100 degree F air.

Because of this simple fact, 40 degree air will reach saturation (100% humidity) much quicker.  So now let’s drag that 40 degree, 100% humidity air into the crawl space that is 50 degrees at 75% humidity.  Not only can it easily handle the moisture coming in, as the air is warmed to 50 degrees its humidity drops and results in the 75% air dropping to less than 75%.  There are a lot of factors, such as air flow, and how much the air flow will reduce crawl space temperature that will effect just how much the humidity will be lowered, but the point remains that the crawl space humidity, overall, will be lowered–not increased.

When you do not control crawl space moisture, bad things can happen

When you do not control crawl space moisture, bad things can happen

So now let’s keep the crawl space temperature at 50 degrees and drop the humidity to a more normal 50%.  The ability of that 50 degree air to absorb moisture in the colder air improves even more.

Interestingly enough, very few crawl spaces ever drop much below 50 degrees except perhaps near the perimeter where the cold of Mother Nature occasionally “takes-out” an outside faucet–at least in the mild Northwest.  Your Mother Nature may treat you differently where you live–it is wise to pay attention to Mother Nature and understand her idiosyncrasies in your area.

Generally speaking, wood moisture content (as measured by a moisture meter) tends to be slightly higher in summer than in winter when outside air is at higher temperature and at lower humidity and then the reverse happens.  75 degree air at 50% humidity will work to raise the humidity of the air in a crawl space with 50% humidity at 60 degrees.  The cooler air in the summer cannot hold as much moisture as the warmer outdoor air and the crawl space air reaches saturation quicker resulting in higher crawl space humidity and thus raising moisture levels in the woodwork.

But before it can become a problem, the seasons change and moisture levels naturally start to go the other way.

Different climate zones are affected by these same principles in different ways–that is why they are called “different climate zones.”  It is important for the builder to understand the climate the home is built in to understand how to allow for these principles to work in ways that don’t destroy the house or provide an environment conducive to wood destroying organisms and mold.

In the South, where humidity can be high year round, and temperatures are near saturation year round, venting crawl spaces at all is especially problematic.

Of course all of this is relative only to “vented” crawl spaces.  Since we have millions of homes with crawl spaces (and more are built every day) any conversation I might have about how they should not be allowed does nothing to deal with the ones that we do have already.

It is more important to understand how to maintain good humidity levels in crawl spaces so that problems do not arise.

By Charles Buell, Real Estate Inspections in Seattle

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The Walking and Crawling Home Inspector

Home inspectors often have to crawl over, under and inside things in the process of inspecting a home. It is not a job for the claustrophobic, or those that do not possess an irrational sense of adventure, or unrealistic curiosity.

Of course every inspector will have their own line-in-the-sand as to what they will do and won’t do, but generally speaking, as a group, home inspectors tend to do what no one else in their right mind would do.

On a recent inspection, while traversing the attic I had to crawl through an unusual tunnel between two chimneys that had been corbelled together so that they could both pass through the roof at just one location.

homeinspectorcrawl1jpg

I guess finding this in the attic I should have been prepared for what it would take to get from one side of the crawl space to the other. I wish I could have filmed myself crawling under this duct.

homeinspectorcrawl2jpg

Laying on one’s back, it was possible to slither under the duct–but it was a little disconcerting having no way to really know what was on the other side until I got there.

Of course it was well worth the trip, as there was extensive water damage in the crawl space on the other side.

It is my business model to do what it takes to provide the best information I can–sometimes it just is not possible and I have to recommend that proper access be made and that I be called back for further evaluation. I don’t like it when I am forced to become one of the things that keep the process from moving along.

Plus, the more difficult the access, the more likely nobody else has been willing to go in there either, and the more likely there will be things that need to be discovered.

By Charles Buell, Real Estate Inspections in Seattle

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