Research the model of your trailer to find whether you have a rubber or metal roof and find the square footage of the roof itself. The rest of the products you use are specific to the materials you are using them on.
Purchase a liquid roof coating and seam tape from an RV dealer. Make sure to purchase enough to cover the entire square footage of your trailer roof.
Clean your trailer roof with a roof cleaner, soap and water or simply wipe away all leaves and dirt with a broom. Be careful on your roof as wet surfaces are slippery and many roofs do not offer much support. You may want to add extra support--particularly to metal roofs--by laying out plywood boards over the roof that extends over the edges as a walkway.
Lay out and apply the seam tape to the seams on the roof where different panels connect. Adding this level of protection before a full roof coat of sealant ensures effective leak prevention.
Apply the roof sealer over the entire roof slowly and in small patches with a disposable brush or putty knife. Cover the edges of the roof down to three inches below the roof on all sides. You may have to apply several coats depending on the brand of roof coating you purchased.
Purchase seam tape and outdoor silicone caulk from a home repair shop or your RV dealer. Make sure you have a caulking gun as well to apply the caulk.
Remove old caulk and seam tape by pulling at the dry material slowly and throwing it away. New caulk and tape will be ineffective if applied over used materials.
Apply the seam tape to any outdoor seams where panels where placed next to each other. The seam tape should be self adhesive.
Caulk around all windows, doors and openings by squirting a small tube of silicone caulk from the caulking gun and running a gloved finger over the seam where the outside paneling meets the opening to ensure effective sealing. It is easy to apply too much caulk but just enough to cover the edges is sufficient.
