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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A Babbling Brook and a Babbling Home Inspector

In a previous post I talked about an abused house with a couple of barely functional bathrooms. I said the story would continue regarding where the water from the bathrooms was actually going.

So here goes.

While the vast majority of the water was still going down the drains, some of the water was leaking into the crawl space due to the condition of the shower walls and leaking at other undetermined locations.

Water was clearly running into the crawl space and had been doing so for quite some time as evidenced in the following picture of the area immediately under the tub/shower.


Here is the picture of that shower if you were fortunate enough to have forgotten it.

Shower in poor condition

Unfortunately this was but the tip of the iceberg regarding the water issues in the crawl space. There was considerable evidence that the crawl space had been flooding with at least 15 inches of water seasonally—and has likely been doing so for the last 50 years. The “quality” of the staining on the walls, the degree of rot in the majority of support posts, the fact that ALL of the form ties were completely rotted away, and the presently saturated ground condition throughout the crawl space—at the driest time of the year, were all testament to a very long standing water intrusion issue. Here is a picture of the obvious high-water line on the foundation and support post.


The fact that the entire space was not infested with Anobiid Beetles was remarkable—but perhaps it was too wet for them. The wood frame of the access door was in fact riddled with Anobiid Beetles—with very recent kick-out of frass present.


To complicate repairs to this situation is the presence of a very cute little brook (a listing perk no doubt) running across the back of the property—less than 30 feet from the house.


This stream, as near as I could tell, appears to be higher than the floor of the crawl space, thereby eliminating any possibility of draining the space by gravity. A sump pump system will likely be necessary—and has been necessary for a very long time.

I think a logical question to ask is: why was anyone allowed to build a house with a crawl space on this site in the first place? Part of the answer is that when the home was built there were likely no regulations that would have prevented it.

….and now I am babbling—-just like the brook.

By Charles Buell, Real Estate Inspections in Seattle

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