The exterior of your home.
Below the roof line of your house, the single most often used access point for rodents is the sub area access door itself. Most access doors and covers do not fit tightly enough to keep rats or mice out. Additionally, some sub area access points have access wells, openings in the ground in front of the doors that either impede the door closing tightly, or are constructed in such a way that rodents can either go around them or under them. If you aren’t sure if rats can get through, crawl underneath and have someone put the lid down – if you can see more than 1/4 of daylight – mice can get in, more than and rats can get in.
If you can’s see light but you can get the first half inch of your finger in any crack, mice can get in.
Common rodent access points include cantilevers. Especially if these extensions happen at the foundation level. A cantilever is an area where your home extends out beyond your foundation. There areas are most common under picture windows or gas fireplaces. It is quite common for builders to either improperly close off the underside, or to not close them off at all. In the picture to the left, a 3/4 wide gap runs the entire length of the cantilever just above the mudsill (the mudsill sits right on top of the foundation.) The C in Control is positioned right in this gap.
Most homes have several concrete features that adjoin each other but were poured at different times and represent different stages of construction. There are slabs and footings, and porches and patios. Sometimes there are gaps between these different features. The two most common of these gaps occur between the foundation of a brick fireplace and the foundation of the rest of the structure, and the gap between a brick facade and the foundation. Both can have gaps that allow rodent access.
The gap at the fireplace can sometimes be found by sticking a screwdriver up under the siding at the sides of the fireplace – sometimes it can only be seen by crawling underneath. The gap behind the brick facade can be tricky and may need a professional to locate. It can sometimes be found at the end and bottom of the facade, it may be buried below ground level.
Exterior vents through, brick, concrete, or wood often allow rodent access, either because they have been damaged, or because they were improperly installed. Vents in brick usually appear as 1/2 to 1 inch wide slits, 3 to 5 inches tall. You may need a flashlight to see inside them to tell if they are screened, although to know for sure that there are no tears or openings in the screen you may have to go underneath.
On some homes, the areas where the utilities attach to your home provide ready access points. Some of these utilities will come up out of the ground at the foundation level, especially the electrical. Look at any area where water, electrical, heat pumps, air conditioning, etc… attach to or penetrate your home.
On our last post we wrote in-depth about the roof and the eaves, but the areas below the eaves are just as important, eave screens and gaps just below the eave line are quite common.
Side framing for overhead door.
The last common area to check is the exterior garage doors. The framing at the sides of the overhead garage door often does not extend all the way down to the concrete. On some of these overhead doors, the door itself does not close completely. This may be due to age, settling, damage to the door, and it may be by design. Finally, the other garage door, the side or back passage door to the outside may have a gap at the base, under the swinging door.
Great, now that you know where many of the common the gaps and access points are, what to do about it? Our newly updated web page http://pestfree.net/Rodent-Proofing.html has some great pointers, as well as some visual guides to the items listed here. Need a professional opinion? We perform an industry leading 5 point inspection and present each customer with a graph detailing what we found and where. Our next post will feature the fourth area – the sub area.
If you are intent on doing your own rodent proofing, please follow the link above, a lot of our work involves redoing rodent proofing done by others, including other rodent control professionals.
If you have rodents, the single most important control aspect is rodent proofing, rodents will always re-infest an area the have infested previously, there is nothing more attractive to rodents than the smell of other rodents. While you may smell nothing – their nose is hundreds of times more acute.
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