It is odd. People do not want rodents in their homes. Yet they often fail to do something as simple as putting one plus one together. That something simple is realizing that rodents are going to enter a crawl space when they have a window of opportunity, such as through numerous holes left by workers or homeowners.

Below are photos taken at a crawl space on a newer home. You can see that a mouse or a rat could easily get into the crawl space at the entry door -- simply by darting in either side of the board at the top of the metal cover. In the lower photo, to make way for a drain on the pan under the water heater, someone tore a foundation vent screen. This is, sadly, often the case when condensate drains are run from furnaces.

One problem is, if these critters get in the crawl space, then they can make a real mess, tearing up the insulation, pulling it down, chewing up the flex ducts and, once they are under the house, they love to travel into the house (can you say looking for real morsels) through the holes in the floor that accommodate the plumbing pipes. Remember, a mouse can get through a hole the size of a dime, and rats can do the limbo to get in a tight place too. Bottom line: First line defence against vermin is to keep them out of the crawl space by not creating, or by blocking, any obvious openings. 

Thanks for dancing by.

Steven L. Smith

Bellingham WA home inspections