Do you know who lives underneath your house? Do you want to know? Old houses are often home to a lot of unwanted visitors in the crawlspace and these unwanted pests can cause major damage to things like ductwork, electrical and plumbing. You need to find an attractive way to keep them out. And just for fun, I’m going to see how many synonyms I can come up with for “critters” (that’s 1).
Old houses were often built with a crawlspace especially in warm climates to allow for cool air to pass underneath the house. This construction was done one of two ways usually, though there are always exceptions.
The first was a masonry stem wall built all the way around the perimeter of the crawlspace with small vents spaced throughout to allow for ventilation. The second is commonly referred to as pier and beam construction, which is simply a series of masonry piers spaced around the underside of the house with structural beams resting on top of them which carry the load of the house.
Both of these methods create openings into the crawlspace, which need to left open for proper ventilation, but sealed off to animal visitors.
Pier and beam construction poses a particular problem for keeping critters out of your crawlspace since there are so many openings to cover, whereas stem wall foundations have relatively few openings to protect.
The Lattice Solution
The solution to the problem with pier and beam foundations is two fold and the first is the decorative part, foundation lattice. Foundation lattice is a historically appropriate addition to any pier and beam foundation and it works great to keep the larger pests out. There are a ton of creative options you can use to dress up your house.
There are the standard designs of vertical, checkerboard, and diagonal checkerboard, but the layout is completely up to you and your creativity. Just make sure the spacing is tight enough to keep the cats and opossums out.
If you want to build some yourself, you can read my tutorial on How To Build Historic Lattice, which tells you everything you need to know.
Stopping the Smaller Animals
Lattice itself won’t keep all the troublemakers out. You also need something to keep the smaller more troublesome pests out like rats and mice. Did you know that a mouse can fit through an opening just 1/4″ wide? It’s true. That’s why they get into attics and crawlspaces so easily.
Lattice would have to be a solid piece of wood in order to keep them out, not to mention the fact that they can chew through wood. So what do you do? Two things:
- Hardware Cloth – This handy material is like insect screening on steroids. It is a wire mesh that comes in 1/4″ and 1/2″ sizes and it should go over any openings into your crawlspace or attic. It’s metal, and so the critters can’t chew through it and when it’s installed behind the foundation, lattice it’s barely noticeable.
- Fill Small Holes – Get out the caulk gun and wood filler and fill in any gaps in your siding and trim. Patch knot holes, caulk joints, anywhere larger than 1/4″ needs to be filled in if you want the varmints out.
Also, keep in mind that these little beasts will burrow under the dirt a little if they really want in, so just running your hardware cloth the ground level may not be sufficient. We typically install our hardware cloth about 8-12″ below the dirt to make sure no one and nothing is getting in unless it packed a shovel.
Other Areas of Concern
While the crawlspace is the biggest problem with these critters getting in, there are also spots like the attic that cause problems. It’s easy to miss 1/4″ holes in your house, especially from 20 feet up.
If you really want to keep everyone and everything out of your house, then go through it and look for any and every way that these boogers can find a way in.
Check eaves, cable lines, power drops, plumbing penetrations. Really anywhere they could get in you need to think of it before they do and seal it off.
Best of luck keeping the home safe, and in case you were counting, that was 7 different words for critters!
Founder & Senior Editor
I love old houses, working with my hands, and teaching others the excitment of doing it yourself! Everything is teachable if you only give it the chance.