Clean the targeted seams with a non-ammoniated cleaning product and a dry cloth. Dry these areas thoroughly before applying the caulk.
Determine whether you need butyl or silicone caulk. Silicone caulk is a general-purpose sealant suitable for small gaps and seams. Butyl caulk is primarily used for outdoor purposes but is a better sealant for large spaces.
Mask the areas you don't want caulked. Load the sealant into the caulking gun, and apply a bead of caulk directly into a seam of the RV.
Moisten your finger with a damp cloth. Glide it evenly along the seam, contouring any edges or frames. Use a small brush or applicator sponge to spread the caulk if the surface is too coarse.
Press the caulk evenly into the seams to secure it, and repeat the process for all desired areas. Allow the sealant to cure overnight, and paint it to match your RV if desired.
