RV Roof Repair and Replacement in Yorba Linda

There are four common constructions and each one repairs differently. Getting this wrong is the single most common cause of a repair that fails within a season.

EPDM is ethylene propylene diene monomer, a rubber membrane typically 45 mil thick, bonded to a plywood or oriented strand board deck. It is the most common roof on towables and mid range coaches. As it weathers it chalks, which is the white residue that streaks down the sidewalls after rain. That chalking is the sacrificial surface oxidizing and it is normal, not a fault, but it does mean the membrane is thinning and it will not accept adhesive properly once heavily chalked without being cleaned back.

TPO is thermoplastic polyolefin. It does not chalk, it is more puncture resistant, and it can be heat welded. It also requires TPO compatible sealants and adhesives. EPDM adhesive on a TPO roof will not bond, and this mistake is extremely common because the two membranes look similar to an untrained eye. We identify the membrane before quoting.

Fiberglass is a one piece moulded or laminated panel. It is walkable, rigid, and it does not have a membrane to fail, but the gelcoat oxidizes and crazes with ultraviolet exposure and the seams at the caps and around penetrations still need maintenance. Aluminum roofs, common on older travel trailers, are sheet stock over bows, which means many more fasteners and many more places to leak.

• EPDM rubber, 45 mil typical, chalks as it ages, adhesive specific
• TPO thermoplastic, heat weldable, requires TPO compatible sealant
• One piece fiberglass, rigid and walkable, gelcoat crazes with age
• Aluminum sheet over bows, more fasteners and more seams to maintain
• Decking underneath is normally plywood or oriented strand board
• Any of the four can hide rotted decking under a membrane that still looks intact

Because they are two different products doing two different jobs, and using the wrong one is the most common reason a resealed roof leaks again within a year.

Self-leveling lap sealant, such as Dicor 501LSW, is formulated to flow after application. On a horizontal surface it spreads out into a smooth continuous film that runs up to the edge of the flange and feathers into the membrane with no ridge for water to sit behind. That continuous film with real thickness is exactly what a flat penetration needs, because water on a roof does not run off, it sits.

Non-sag sealant, such as Dicor 551LSW, is formulated to stay where it is put. It goes on vertical surfaces: the front and rear cap edges, the roof to sidewall transitions, the vertical faces of a raised trim. Put self-leveling on those and it runs off, leaving a thin drip line with almost no film build at the top of the joint, which is precisely where the seal is needed. That job fails within a season and it looks fine from the ground the whole time.

Both products also have to be compatible with the membrane and with whatever sealant is already there. Silicone is the enemy here. Once silicone has been used on a roof, nothing else bonds to that area until it is mechanically removed, and we have removed a great deal of silicone from roofs that somebody sealed in a hurry.

By closing the water path before the structure absorbs it. The sequence from small leak to five figure repair is entirely predictable, which is why we can be so specific about it.

Water enters at a failed penetration, typically an air conditioner gasket, a vent flange or the refrigerator vent. It does not appear on the ceiling. It sits on top of the ceiling panel and runs along a roof framing member until it finds a low point, then wicks into the plywood decking and into the lauan substrate of the sidewall at the roof to wall joint. That substrate is the layer the outer skin is bonded to. Once it swells and softens, the adhesive bond between skin and substrate lets go, and the sidewall separates. That is delamination, and it runs $1,500 to $20,000 and up at 10 to 100 hours to repair.

The reseal that would have prevented it is $750 to $4,500 at 4 to 20 hours, and the low end of that band is a normal maintenance visit on a coach whose roof is otherwise sound. Water damage restoration and subfloor replacement, the other downstream cost, runs $750 to $15,000 and up at 4 to 60 hours. The arithmetic is not close.

Penetration failures are around a component: a vent, a fan, an antenna base, an air conditioner, a solar mount foot. The sealant around the flange has cracked, shrunk back from the edge, or lifted. These are maintenance failures and the repair is to remove the old sealant back to a clean bond surface and apply new, which is what a reseal job is.

Seam failures are along a joint between two structural elements: the front cap to roof, the rear cap to roof, the roof to sidewall transition, or a factory membrane seam. These are not maintenance failures. They are adhesive or mechanical failures in a joint that carries movement, and running a bead of sealant over the top of one is cosmetic. The correct repair removes the trim or rail, cleans the joint back to substrate, replaces the butyl tape underneath, refastens, and then seals the outside.

The distinction shows up in the leak pattern. A penetration leak stains in one place and gets worse in heavy rain from above. A seam leak at the sidewall transition stains along a wall, often several feet long, and gets worse when the coach is parked with that side downhill or in driving rain from that direction.