Make your motorhome impervious to unwanted critters by eliminating the small openings they can squeeze through to gain access to your coach interior.
By Craig Guest, F274321
July 2002
Living in the country has its advantages and disadvantages. On the upside, we enjoy clean air, quiet nights, and star-filled skies.
On the downside, mice can be a big nuisance. I have problems with mice nesting in the generator compartment of our 2000 Allegro Bay motorhome and entering the coach through the engine access cover. Fortunately, damage has been minimal so far (a chewed-up air filter and throw rug) but unacceptable nevertheless. I have tried traps, poison, electronic deterrents, and even mothballs (which, by the way, work “”if moths are your problem). Nothing was effective. Unfortunately, the only real solution to mouse problems is to block their entry paths entirely.
With this in mind, I purchased the following items from my local hardware store:
1 2-foot-by-10-foot piece of 1/4-inch galvanized wire screen material
50 ½-inch #8 self-tapping screws
50 flat washers for #8 screws
1 36-inch-by-36-inch piece of aluminum window screen material
12 feet of window screen framing
4 corner moldings for the screen frame
1 screening tool and enough screen ribbing to install the aluminum screen to the frame
2 36-inch-by-36-inch-by-1-inch pieces of aluminum angle (1/16-inch thick)
1 can of spray foam insulation (minimal expansion type)
(Author’s note: Materials and quantities vary with the application.)
My motorhome’s engine access panel fits well and looks good, but a mouse had no trouble squeezing its way in. In addition, the carpet that was exposed on the underside of the cover became a source of bedding material for the mice to take back to the generator for their nests.
I began by framing the motor access opening inside the coach with the aluminum angle and self-tapping screws. (This makes a suitable surface on which to fasten the screen frame, but may not be necessary in all applications.) Next, I carefully built a screen frame to fit the opening, being sure to keep it small enough so that the outer access cover would easily fit over it. I fastened the frame to the angle metal and the firewall with self-tapping screws. I then installed the aluminum screen on the framing, making sure that fit and finish were very close and did not interfere with the engine or the underside of the outer cover. The screen can be detached easily for engine servicing by removing the screws that hold the frame in place. (Keep in mind; you could have other openings in your coach. A thorough check, especially under the vehicle, must be done.)
After I had the coach secure, I began to enclose the generator compartment with the 1/4-inch screening. I chose the larger, heavier screening for two reasons: to ensure good air circulation around the generator, and because the screening is exposed to the outside, where lighter material could be damaged by debris during traveling. I cut the wire in premeasured sections, starting under my coach at the rear of the generator. The self-tapping screws and washers made fastening the screening a relatively quick process. What did become time-consuming was fitting the screening around all the nooks and crannies and feeding the generator fuel line and wiring through it at predetermined locations. Care must be taken to protect the lines and wiring from abrasion where they pass through the screening. To prevent abrasion caused by generator vibration, I fastened a small piece of white garden hose, approximately 1-1/2 inches long, around the fuel line where it passes through the wire mesh and fastened it with cable ties.
After securing the rear of the compartment, I began to fasten wire to the bottom area, making holes for the oil drain tube, the exhaust pipe, and the exhaust pipe bracket at the appropriate places. I also used white garden hose to connect to the oil drain valve. The hose makes draining oil from the generator a much cleaner operation.
When I finished enclosing the generator, I went back and used the spray foam to seal any voids that were impossible to cover with the screening. (The spray foam really expands, so I used the minimum-expanding type, sparingly.) Keep in mind that a mouse can fit through an opening not much larger than a pencil. A good, close fit is critical everywhere, including the seal around the generator access door.
It has been several months since I have made these modifications. So far, I have seen no further signs of mouse activity in my mobile house.