Q: I have had an all-aluminum trailer since 1999. It’s garage kept, and I don’t haul as much as I did formerly so it hasn’t needed any major cleanups in a while. This week my mare gave me a reason to pull out the mats, and I can see some pitting and a few small holes spaced here and there. These don’t really seem to be in areas where the horses stand, but it’s making me nervous. In past trailering articles, you’ve explained how to check wooden floors for rot. How can I tell when an aluminum floor needs replacement or repair? If it can be repaired, how should that be done?

A: It sounds like you take great care of your trailer, by cleaning it and storing it indoors. No matter what your trailer is made of, the first rule in preventing floor rot is to keep it as clean as possible, which means using shavings to soak up urine and hosing them off after every use. It’s also important to take the mats out frequently, wash and dry both mats and floor with soap and water or a high-pressure washer, and then let everything dry thoroughly before putting the mats back in.

When a trailer is not kept clean enough, the acid in urine corrodes the aluminum, resulting in pitting, white flakes and eventually holes. Urine that sits under the mats for weeks at a time is detrimental to the structure of an aluminum floor. In the used trailers I see, the rotting generally occurs in the middle of the trailer floor.

To check for structural integrity, take the mats out and, in good lighting, closely inspect the floor for damage. Get in and jump around on the floor in many different spots, looking for any squishy or weak areas. 

Holes are obviously not a good sign, but with minor pitting, generally the floor will still be sturdy, based on the support of the I-beam or frame of the trailer. You may want to climb under the trailer and look for rust or corrosion on the frame as well, especially if you live in an area where salts or chemicals are laid on the roadways in wintertime. 

Weak spots or holes can be repaired. If you have a full-sheet aluminum floor, a trailer-repair facility can put down a new sheet over the whole floor or, if you have the extruded-plank style, they may be able to cut out damaged areas and piece in replacement sections. Repairs must be made by a professional aluminum-certified welder to ensure the new aluminum bonds well with the existing trailer floor and frame and is safe and sturdy. 

Your trailer dealer can refer you to reputable trailer-repair facilities. We want to haul our horses as safely as possible as well as to protect our trailer investment. The best way to do this is to be vigilant on cleaning, maintenance and inspection of our trailer components.

Stewart Gulager, Twister Trailer, Fort Scott, Kansas

This article first appeared in EQUUS issue #441.