--- title: "Full RV Roof Replacement Cost | Rancho Santa Margarita" description: "Strip to the rafters, replace lauan or OSB decking, lay new EPDM or TPO and rebed every penetration. 20 to 80 hours at $210, performed indoors in Yorba Linda." focus_keyword: "full rv roof replacement rancho santa margarita" canonical: https://ocrv.me/services/roof-repair-and-replacement/full-roof-replacement/ kind: subService updated: 2026-07-29 source: OCRV Center --- # Full RV Roof Replacement in Rancho Santa Margarita: Membrane and Decking > Everything comes off: air conditioners, vents, racks, trim and the sheet itself. **Decking is inspected rafter by rafter**, then a new membrane goes down in one piece. **$3,500 to $18,000+**. ## What happens during a full RV roof replacement? Full roof replacement strips every rooftop component, removes the old membrane, renews rotted lauan or OSB decking over the rafters, lays a new EPDM or TPO sheet, and rebeds every penetration. Rancho Santa Margarita owners get this done indoors at our Yorba Linda shop where adhesive conditions are controlled. - Air conditioners, vents, racks and edge trim all come off first - Decking is replaced in full sheets landing on rafters, not patched - New decking thickness changes the air conditioner gasket requirement - Twenty to eighty labor hours depending on length and substrate condition ### Key facts | Item | Value | | --- | --- | | Price range | $3,500 to $18,000+ (20 to 80 labor hours at $210 per hour) | | Labor rate | $210 per hour (Plus body supplies at $5 per body hour) | | Typical turnaround | 6 to 15 shop days (Adhesive cure and full decking replacement drive the calendar) | | Estimate | $150 written ($150 buys the written scope. It is credited back at authorization) | | Rafter spacing | Usually 16 inch centres (Some older builds run 24 inch, which changes decking thickness) | | Deposits | 50 percent over $2,000, further 25 percent over $10,000 (Taken when parts and materials arrive on larger jobs) | There comes a point where patching a roof is throwing labor at a surface that has run out of service life. Usually it arrives one of three ways: the decking has rotted across too much area to cut out sensibly, the membrane has embrittled everywhere rather than in one place, or somebody adds up the cost of eleven patches and realises a single new sheet is cheaper and better. A full replacement is a strip to the structure. Air conditioners come off, vents come out, the antenna, the racks, the solar and the edge trim all come away, and then the membrane is peeled and the substrate underneath is finally visible for the first time since the unit was built. Most owners are surprised by what that reveals. We photograph all of it, because that photograph is what explains the final invoice. ## The point where replacement beats repair There is no single trigger, but there are three that account for nearly every full replacement we do. The first is decking condition. Once soft areas appear in more than two separate zones, cutting each out leaves a deck that is more joint than sheet, and joints are where fasteners loosen and where the membrane above eventually telegraphs. The second is the membrane itself. A sheet that tears rather than stretches under a probe has lost its elongation across the whole roof, not just where the damage shows. Patching it moves the weak point to the patch perimeter, and that is exactly why those repairs fail so predictably about a year later. The third is simple arithmetic. When somebody brings us a roof with nine areas needing attention, we price the patches and we price the reskin, and the two numbers are often much closer than expected. Given a close call, one continuous sheet with one perimeter beats nine patches with nine perimeters every time. ## What is actually under the membrane on an RV roof Peel the sheet and you find decking, usually lauan in an eighth, quarter or three eighths inch thickness, sometimes OSB on entry level trailers. Under that are the rafters, typically aluminum tube on modern builds or wooden members on older ones, most often at sixteen inch centres although twenty four inch spacing shows up on some older units and on a few lightweight designs. Rafter spacing is not trivia. It determines what decking thickness is appropriate, whether the roof is safe to walk, and how a replacement sheet has to be laid out so its joints land on structure. It also explains why hail fractures and foot damage always appear between trusses rather than over them: the bay is the unsupported span and it is where the load has nowhere to go. The other thing that shows up at this stage is truss condition. Aluminum tube corrodes at the sidewall junction where water has been collecting, and wooden rafters rot at their ends for the same reason. Neither is visible until the decking is off, which is why we photograph every bay before new material covers it. - Lauan at 1/8 to 3/8 inch, or OSB on some entry level builds - Rafters usually at 16 inch centres, sometimes 24 on older units - Trusses fail at the sidewall junction where water pooled - Decking joints must land on a rafter, staggered between rows ## Choosing the new membrane and whether to change families Most replacements go back with the same family the coach left the factory with, because the edge trim, the adhesive system and the installer's technique all line up. EPDM at 45 mil is the traditional choice and it is forgiving to install. TPO and Alpha Systems SuperFlex are heat welded, which produces a genuinely continuous seam at any joint and does not chalk, so the sidewalls stay cleaner. Changing families is possible and it is a real decision rather than a formality. Going from EPDM to TPO means a different adhesive system, a welding setup rather than a bonding setup, and occasionally different edge trim to suit the sheet thickness. Owners who are tired of black streaks on white sidewalls sometimes make this change deliberately, and it is a reasonable reason to do it. **Full replacement membrane options** | Option | Install method | Streaking | Notes | | --- | --- | --- | --- | | EPDM 45 mil | Bonded with matched adhesive | Chalks and streaks by design | Traditional, forgiving, widely stocked | | TPO | Heat welded seams | No chalk | Continuous welded joints, cleaner sidewalls | | Alpha SuperFlex | Heat welded with matched primer | No chalk | Common on late model towables | ## The details that decide whether a new roof lasts The membrane is the easy part. What separates a roof that goes twenty years from one that leaks in three is what happens at the edges and the holes. Every flange has to come down onto fresh butyl. The edge rail has to be bedded and then sealed with a non sag product, because self leveling sealant on a vertical face just runs off and leaves the fastener line exposed. The air conditioner gasket deserves its own paragraph because it catches people out constantly. Changing decking thickness changes the gap the gasket has to fill. Refit the original three eighths gasket where the roof is now thicker and you crush it. Refit it where the roof is thinner and it never seals. We measure finished roof thickness and fit the gasket that matches, then torque the mounts to the compression the manufacturer specifies rather than to feel. > **note:** We do this work indoors. Adhesive flash times, humidity and wind all change the result, and a marine layer morning in June is not a condition you want a roof bonding in. ## Cost, deposits and how many days to plan for Full replacements bill at $210 per hour from the body and paint department with body supplies at $5 per body hour. Twenty hours is a short trailer with sound decking and two vents. Eighty hours is a forty five foot fifth wheel needing complete decking, two air conditioners reset and a solar array removed, catalogued and refitted. Parts carry standard markup, tax applies to parts and materials, labor does not. Plan on six to fifteen shop days. Deposits are 50 percent above $2,000 with a further 25 percent when parts and materials arrive on jobs over $10,000, and most full roofs clear the first threshold comfortably. $150 buys the written scope. It is credited back at authorization. > **price:** Rafter damage found after the decking comes off is a real scope change, not a surprise charge. It is quoted separately, with the photographs of the bay it was found in attached. ## Insurance on a full roof replacement A roof that aged out is not a claim. A roof written off by hail, a fallen tree, a collision or a storm event usually is, and a full replacement is frequently the correct outcome on those files once the damage is scoped honestly. What complicates them is betterment: a carrier is paying to restore a twelve year old roof, and some policies depreciate that component. The other recurring issue is teardown discovery. The scope written before the membrane came off was written blind, and rotted decking or a corroded truss found underneath is exactly what a supplement exists for. Those get approved when there are dated photographs of each truss bay and a written note tying the finding to the original loss. They stall when there are not. ## Units we reskin most often Towables dominate this work. Travel trailers and fifth wheels carry large flat roofs with many penetrations and often the thinnest decking, and they tend to spend more of their lives parked outdoors than motorhomes do. Park models are their own category, because a unit that has stood on one pad for fifteen years under trees has usually accumulated everything a roof can accumulate. ## Cost $3,500 to $18,000+, based on 20 to 80 labor hours at $210 per hour. Written repair estimate is $150, credited in full against an authorized repair. All work is performed in shop. ## Questions and answers ### How many days does a complete RV roof replacement take? Six to fifteen shop days for most units. Stripping every rooftop component, peeling the membrane, replacing decking, bonding a new sheet and rebedding all the penetrations each take real hours, and adhesive open and cure times cannot be compressed to suit a pickup date. ### Can a new membrane be installed over the existing one? It should not be. The new bond is only as strong as the failed adhesive layer beneath the old sheet, and leaving the original membrane in place hides the decking condition that usually motivated the job. Every roof we replace is stripped to the substrate before anything new goes down. ### Can I switch from an EPDM roof to TPO during replacement? Yes. It means a different adhesive system, heat welding equipment instead of bonding, and sometimes different edge trim for the sheet thickness. Owners usually make the change because TPO does not chalk, so the black streaks that run down the sidewalls of an EPDM equipped coach stop appearing. ### Why does new decking change the air conditioner gasket? Because the gasket has to fill the gap between the air conditioner base and the finished roof, and changing decking thickness changes that gap. Reusing the original where the roof is now thicker crushes it. Reusing it where the roof is thinner leaves it loose. We measure and fit 3/8 or 1/2 inch accordingly. ### Can the price go up once the old roof is off? It can, and the reason is always decking or rafters that were invisible until the membrane came away. We photograph every truss bay before covering it and quote any additional work separately with those photographs attached. What we do not do is absorb a discovery quietly and hand you a larger number at the end. ### What happens to my solar panels during a roof replacement? They come off. Panels, mounts and wiring are removed, catalogued and refitted on new mounting points with fresh butyl and sealant afterward. Working around an array guarantees a leak next to a brand new roof, and the mounting feet are one of the most common penetration leak sources we find. --- Source: [OCRV Center](https://ocrv.me/services/roof-repair-and-replacement/full-roof-replacement/). Last verified 2026-07-29.