Best Types Of RV RoofsAnthony Day
The roof on your mobile home is more than just a barrier to keep the sun and the rain out. So what are the best types of RV roofs?
Good insulation properties are essential to limit the temperature differential inside and outside the RV. The roof must also be light, durable, and aerodynamic to minimize the vehicle's fuel consumption.
The materials for RV manufacturers are polymers such as EPDM and TPO or the more conventional aluminum sheeting or fiberglass panels. Avoiding leakage makes EPDM and TPO the two best options to select in modern RV construction. Thermal insulation below the roof will provide comfort.
An RV roof is seldom a single material such as EPDM or TPO but rather a sandwich-type construction of several layers providing strength and rigidity, insulation, and a UV-stabilized upper membrane layer to seal the roof.
Let's look at the four upper-layer roofing materials used to construct modern RVs and camper trailers.
The Best RV Roof Top Layer To Use and Why
RV manufacturing companies favor EPDM (Ethylene Propylene Diene Monomer) rubber sheeting as their material of the first choice for rooftop finishing. The EPDM is available in a range of upper surface finishes, but the bottom side is always a black rubber surface that can be bonded to the roof support structure.
EPDM is also easy to install as a DIY repair solution on a leaking RV roof. The material is supplied in rolls of various thicknesses, and the installation, maintenance, and repair of the installed EPDM are relatively simple.
EPDM is more heat absorbent than other RV rooftop finishes, which can be an advantage in the winter but a severe disadvantage in summer. The material is soft and can be penetrated or torn by low-hanging branches.
TPO (Thermal Poly Olefin) rubber sheeting is a very good second choice. The TPO is similar to EPDM but can be distinguished by the bottom side being white. The surface of the TPO is available in a range of colors, but the bottom side is always white and is bonded to the roof support structure.
The easiest way to identify whether your RV is fitted with EPDM or TPO is to remove one of the roof vent finishing covers and see where the roofing material has been stapled to the underside of the roof core material.
Turn a corner over and check the color of the bonded side on the material. If the material is black, then it is EPDM, and if it is white, it is TPO.
TPO is a single-ply material that is lightweight and easy to install on a new or refurbished RV roof. Like EPDM, the TPO must be bonded to the roof's core. The TPO is more affordable than EPDM but does not offer the same durability.
The supply quality of TPO is not as consistent as that of EPDM in the US, so follow what the local RV manufacturers recommend in your area.
Old Favorites For RV Roofing Materials
The Airstreams made aluminum RVs iconic in the US, and they have remained very popular. Aluminum has been a favorite RV construction material for many decades, but it has some downsides that have to be considered.
Even though aluminum is the lightest metal for the construction and fabrication of lightweight vehicles, it no longer offers the best strength by weight material for the construction of RVs. The biggest drawback is that aluminum absorbs heat easily and is incompatible with modern chemical glues.
Aluminum is very durable and can withstand more physical abuse than the rubber polymers used for RV roofing. There are very few RV manufacturers still using aluminum paneling for roof cladding.
Glass fiber has been used as a roofing material on RVs. It has proven strong, durable, and smooth. Glass fiber roofing is much heavier and thicker than other types of roofing material and thus costlier in terms of fuel consumption.
Glass fiber is rust and rot-resistant, and the gel coat finishes allow an endless range of color options. Unfortunately, glass fiber does not withstand the onslaught from the sun well and is prone to hardening and cracking over time.
A repair of glass fiber roofing is more expensive than the polymer rubber alternatives and requires some level of expertise in working with the glass fiber chemicals.
Modern Composite RV Roof Construction Materials
A cross-section through the roof of a modern RV will likely reveal a sandwich-type construction of various materials used to provide strength, thermal insulation, structural rigidity, and a leak-proof shell.
A layer of EPDM or TPO provides the outside skin of the RV roof as these materials are waterproof, UV resistant, Ozone resistant, easy to install, and very durable. The top surface is typically bonded to a hard surface of thin plywood or fiberglass with aluminum frame supports.
The cavity between the outer surfaces is filled with polyurethane foam to provide thermal insulation. The ceiling can be finished in a soft-touch material or a hard easy-to-clean surface material.
The most critical aspect is to ensure that the top layer of the roofing is EPDM or TPO to ensure that the roof is weatherproof and will protect the rest of the RV from moisture ingress and heat absorption.
Cladding An RV Roof With A Weatherproof Membrane
The roof and the undercarriage of your RV are most vulnerable to deterioration due to penetrations, rust, or leakages. The undercarriage is best protected by the treatment of a polyurethane spray-on protection coat.
The roof of an RV can be retrofitted with EPDM (Ethylene Propylene Diene Monomer) or TPO (Thermal Poly Olefin) rubber sheeting. These materials are supplied in various thicknesses and come in rolled form.
The EPDM or TPO rubber sheeting can be cut to size and glued onto the roof or your RV using a cyanoacrylate adhesive. It is never recommended to drill holes into your RV's roof for the fitment of roof racks, air-conditioning, antennae, or skylights, but it is often unavoidable.
Ensure that the holes drilled into the roof are supported from below with sufficiently strong framing material and that the heads of the screws are countersunk. You should apply butyl putty around the hole and the screw head to form a watertight seal.
The roof membrane can be glued over the top of any screw heads once the fitment of the rooftop accessory has been completed. The soft, malleable EPDM or TPO rubber sheeting will form a protective barrier on top of the roof and prevent moisture penetration or corrosion.
Before adhering to the EPDM or TPO rubber sheeting, ensure that the roof surface is clean and dry, and free of any loose paint or corrosion. Repair the surface beforehand and wipe the roof surface with an isopropyl alcohol microfiber cloth.
The alcohol will help any moisture evaporate from the roof surface. Apply the glue to the roof surface and spread it evenly with a broad plastic spatula. Allow the glue to become slightly dry until it is still tacky to touch.
Now roll on the pre-cut rubber sheeting and use a roller to roll out any air trapped between the roof and the rubber sheeting. Place some flat, heavy objects on top of the roof to weigh down the sheeting and allow the bond to cure in a cool, dry place.
Adhesives For EPDM Bonding To RV Roofs
EPDM (Ethylene Propylene Diene Monomer) or TPO (Thermal Poly Olefin) rubber sheeting is the materials of choice for RV manufacturers, DIY builds, and RV roof repairs and resealing.
EPDM can be glued to almost any surface, including wood, ply-board, glass fiber, aluminum, and even concrete. Several solvent and water-based adhesives are recommended for bonding EPMD to a variety of surfaces.
Neoprene Bonding Adhesive is available in a one-gallon container and is a solvent-based adhesive ideal for gluing EPDM to wood, metal, or concrete surfaces. The one-gallon container will cover a bonding surface of 75 to 100 square feet and costs $35 per unit.
Neoprene Bonding Adhesive is a solvent-based contact adhesive offering a near-instant bond when the coated bonding surfaces are brought into contact. Use a solvent-resistant roller to apply the EPDM in a thin uniform layer and allow it to flash dry.
Work in a well-ventilated area as the evaporating solvent is a strong chemical that can cause repertory issues. Wear a face mask, gloves, and eye protection when working with this adhesive.
The solvent-based EPDM adhesive is best suited for sloped surfaces and must be applied on both surfaces being bonded. The adhesive is effective on EPDM to rubber, metal, wood, or cement surfaces.
Latex Bonding Adhesive is available in one-gallon containers at the cost of $43 per unit. This is a natural rubber, water-based adhesive for bonding EPDM to wood surfaces. A one-gallon container will provide coverage of 150 square feet of bonding surface.
The water-based Latex adhesive is ideal for bonding EPDM to low gradient or flat roof surfaces such as plywood or fiberboard. The advantage of using the Latex Bonding Adhesive is that it only needs to be applied to one of the bonding surfaces.
The adhesive can be rolled or brushed onto the surface of the roofing material before applying the EPDM membrane. As the adhesive is slow to cure, the EPDM can still be moved and rolled to get rid of any air trapped.
Adhesives For TPO Bonding To RV Roofs
TPO (Thermal Poly Olefin) rubber sheeting is one of the materials for RV manufacturers, DIY builds, and RV roof repairs and resealing. The TPO can be distinguished from EPDM in that both sides of the TPO are colored, whereas EPDM always has a black contact side.
Weather Bond Low VOC Solvent-Based TPO/EPDM Bonding Adhesive is a quick-drying solvent-based adhesive ideal for bonding TPO and EPDM to roof surfaces such as wood, fiberboard, metal, or metal concrete surfaces.
The low Volatile Organic Compound (VOC) designation means that the amount of solvent evaporating into the air is less than 250 grams per liter and is in compliance with the state of California Clean Air Act of 1988 and the updated version of 1997.
The adhesive is supplied in 5-gallon containers at $350 ($70 per gallon) and provides coverage of 60 square feet per gallon. More adhesive may be required on porous or irregular material surfaces.
The adhesive is a quick contact type that is to be applied on both bonding surfaces and allowed to flash off for some time before bonding the two surfaces together. Carefully roll the TPO surface onto the RV's roof, taking care to avoid getting air trapped.
Despite the adhesive being designated as a low VOC bonding adhesive, be aware that it is highly flammable. Protective gloves, eyewear, and a chemical respirator should be worn when working with this material.
Lucas Universal 8800 bonding adhesive is a low VOC water-based adhesive designed to bond TPO and EPDM single-ply membranes to a variety of roofing materials. A one-gallon container costs $160 and will provide coverage of 120 to 200 square feet per gallon.
The adhesive must be applied to both surfaces to be bonded with a half-inch nap roller and allowed to dry until it is dry to touch. The TPO can then be applied to the RV roof surface and rolled to expel any air trapped.
The temperature must be higher than forty degrees Fahrenheit, and the humidity must be below 90% when working with this adhesive.
Repairs Of Aluminum Or Glass Fiber RV Roofs
Aluminum or fiberglass RV roofs are less common on modern builds but were quite common before the use of lightweight composites covered with EPDM or TPO became the most common RV roof construction method.
The aluminum panels were most likely attached to the RV frame by aluminum pop-rivets, and the joints were sealed with butyl tape. Corrosion and the loss of butyl rubber may cause the old Airstream to lose the ability to keep moisture out.
The repair is a tedious task of drilling out the old pop-rivets, cleaning and re-bonding the seams with fresh butyl tape before pop-riveting the seams together again.
Glass fiber is much easier to repair but requires all the cracks to be ground down to bare fiberglass and re-glass the cracks before resealing the roof with a gel coat. All holes through the fiberglass roof must be cleaned and filled with glass fiber-filled epoxy resin.
Once the resin has hardened, the screws fixing the rooftop accessories can be reattached using butyl tape to create a weatherproof gasket at each hole and screw head.
About THE AUTHOR
Hi, my name is Anthony, and RVs are what I'm passionate about. I bought my first RV when I was 21, and I've been hooked ever since. I'll guide you on how they work, how they can be used in different environments, and how they fit into our everyday lives.Read More About Anthony Day