RoofWrap Mobile Home Reroof System Installation Instruction Guidelines
Important General Information
Please read this following thoroughly before proceeding with the installation. Make sure all necessary materials and tools are readily available.
All mobile homes may appear similar in design. However, when you step onto the roof you may notice several distinguishing features particular to each some. The location of the roof trusses is especially critical to the proper installation of the roofing system. These will be used to support the weight of the new roofing, the installers and provide the substrate for roof membrane attachment.
Perform all work on the roof membrane with clean, soft-soled shoes. Provide a mat at the top of the ladder with which to clean shoes. Do not allow the membrane contact with coal tar, asphalt, oil or grease.
The kit includes the single roll of RoofWrap EPDM roof membrane, all attachment materials, vent flashings and sealants. Doublewide homes utilize two seamless sheets that are overlapped and spliced at the center ridge.
RoofWrap Word Definitions:
- EPDM: The acronym for the base rubber polymer of RoofWrap membrane.
- Membrane: RoofWrap EPDM sheet of white or black rubber measuring 45 mils thick and weighing .345 lbs./sq. ft.
- Cover Tape: The 6"- wide white or black adhesive tape backed EPDM use to flash field termination bars and various details.
- Uncured Cover Tape: A flexible and formable version of Cover Tape.
- Seam Tape: A butyl adhesive tape used for adhering and sealing RoofWrap membrane laps.
- RMS Tape: A 6-inch reinforced EPDM strip of which 3 inches is adhesive taped. Used with Screws and Plates under the membrane to secure it at changes in roof deck slope and angles.
- Splice: The overlap and mating of two pieces of RoofWrap membrane laps.
- Tape Primer: A liquid primer used to prepare RoofWrap for application of adhesive tape backed products.
- Primer Pad: An application pad for use with Tape Primer.
- Lap Sealant: A caulking used to seal exposed edges of RoofWrap flashings.
- Protrusions: Stacks, vents, poles and hoods located on the roof deck.
- Cold Protrusion: Roof vent stacks that do not exceed 120-degrees F. commonly venting the kitchen and bathroom.
- Hot Stacks: Roof vent stacks that exceed 120-degrees F. from heat producing appliances.
- Furnace Collar: An insulated metal that surrounds furnace and other hot stacks.
- Pipe Hood: A prefabricated roof penetration flashing accessory. Made from plastic or metal.
- Retrofit Pipe Boot: A Pipe Boot that can open to fit around protrusions that cannot be disconnected such as a power pole.
- Termination Bar: The aluminum bar that, with screws, secures the roof membrane to the perimeter fascia and roof deck.
- Screws and Plates: The means for mechanically attaching insulation board and RMS Tape to roof deck
- J-Channel: A "J" shaped metal trim, mounted near the top of exterior sidewalls that serves as a water diverter and termination bar.
- L-Metal: A prefabricated metal flashing that is bent to a 90-degree angle. Used on roof edge.
- Flashing: A metal or membrane piece that seals and covers a specific area of potential water entry.
- Tip Out: A roof area that is separate from the main roof yet is attached and adjacent.
Recommended Tools and Equipment For Two Workers
1. Two 10' heavy-duty stepladders
2. Two electric drills with Hex head bits
3. Two heavy-duty 50' extension cords
4. Two pairs of scissors - small and large
5. Two razor blade utility knives
6. One caulking gun
7. One hammer
8. One steel measuring tape
9. One pair pliers
10. One pair straight metal snips
11. One hack saw
12. One quart mineral spirits
13. One small pry bar
14. Push broom
15. Erasable marker
16. Plywood (4' X 4') for cutting surface
17. Sheet metal coil - 26 gauge minimum
18. Scaffolds - one or two (optional)
19. 2" Nylon or steel handheld roller
20. Chalked snapline
Jobs using roof insulation board need a power and keyhole saw.
Comply with all applicable safety and building code laws.
1) Preparation of the Existing Roof Surface
Use a push broom to sweep the roof clean and dry. Cover any fresh tar or asphalt coatings with two layers of 4-mil polyethylene. The surface must be clean, dry, free of grease and oil and without any irregular or sharp points that may damage the installed membrane. Weak or broken deck or metal roofing seams require an overlay of plywood screwed to the deck.
2) Preparation of Roof Protrusions
2.1 On a mobile home, there is generally a furnace stack, one hot water stack, one or two soil pipes (depending upon the number of bathrooms) and an exhaust vent from the kitchen and bathroom. Another protrusions may include a roof mounted power line pole. That will require a special RoofWrap Retrofit Pipe Boot. Some roofs will support an evaporative (swamp) cooler. There may also be attic condensation vents and a woodstove chimney pipe.
2.2 Remove all vent and fan hoods, flashing collars and other pieces so as to allow the membrane to be placed over the protrusion or opening. The removed covers can be reinstalled, or replaced with new, near the job's completion. When using the web site's Online Price Calculator, indicate whether or not you will be reusing your existing vent flashings by selecting the of number of new vents in each category.
2.3 Soil vents are used above bathrooms to carry plumbing gas exhaust . Here, when using the Steel Plumbing Vent Caps, cut the pipe as necessary to extend through the Vent Cap's base - approximately two inches, but no more than 2.5" or 3/8" from underside of the cap. Place a layer of duct tape over any cut pipe edges. The Kitchen and Bathroom Fan Vent Flashing Hoods are supplied with a maximum length extension below the flange. This allows for greater flexibility when attaching the ducting to the base of the vent. This extension may be trimmed shorter if it otherwise impedes the proper duct alignment and airflow. Use the supplied zip tie to attach the flexible duct to the bathroom fan vent.
2.4 When removing old condensation vents, reach into the rafter cavity and feel for condensation in the insulation. If the insulation is damp, consider adding one or more vents. This cost is not included in the kit.
2.5 Furnace and hot water stacks have a "safety collar" around the base. There are a wide variety of these collars. The membrane or EPDM flashing must be attached to the outer insulated collar.
3) Roof Insulation and Installation (optional)
(Skip to Section 4.1 if no additional roof insulation is to be used)
3.1 RoofWrap does not supply insulation board for economic reasons. Sourcing your insulation from a local building material or roofing supply firm can eliminate the added cost of freight and potential damage. This will save both time and money - keeping your total cost as low as possible.
3.2 There are three insulation types recommended for your consideration. Expanded Polystyrene (EPS) is a white "bead board" product ranging from 1" to 5" in thickness. For roofing purposes, specify a minimum one-pound density product. Standard sheet size is 4 'X 8'. Special order lengths may include 10, 12, 14 and 16 feet. The average R-value of EPS is 4.00 - 4.12 per inch. EPS offers a lower cost with a lower R-value. If R-value is of secondary concern, EPS may be your best choice. EPS is not known for its fire resistance and has no facers. Extruded Polystyrene (EXP) is a closed cell, thermal plastic board material. It is resistant to moisture and has good strength, durability and long-term R-value. EXP has no facers. Its R-value is 5.0 - 5.5.
Polyisocyanurate (also called "poly" or "iso") is an expanded form insulation with felt facers. It is not known for its moisture resistance but is quite strong, fire resistant and has an R-value of 7.0 - 7.3 per inch. Polyiso is the best value if R-value is your objective.
3.3 Most installations use a single or double stacked 1.75-inch thick insulation board. In order to obtain proper attachment, the screws must properly penetrate a roof truss or wood framing. Identify the location of the trusses before any work begins. Designate their exact location with a erasable marker on the exterior wall, of both sides, below the point where the membrane will terminate. Do not shorten the protrusion pipes until after installing the insulation board. Then measure as previously described. Depending upon the insulation's thickness and the pipes' height, pipe extensions may be needed. Use the same diameter PVC pipe to fabricate the extension.
Begin installation by building a perimeter of 2" X 4" nailers laid flat. The outer edge of the nailer should be in line with the exterior wall's plane. Screw the wood nailer every two feet to a structural wood support. This will serve as a firm and walkable edge that will avert damage to the unsupported and fragile insulation board edge and provide a clean look to the finished edge. Lay the first row of 4' X 8' insulation boards lengthwise running the length of the roof. The next, and every other row, should start with a piece cut into a 4' X 4' size. This will result in a staggering of the board ends. When fitting over protrusions, cut an opening in the insulation just large enough to slip over the unit. Once the insulation boards are laid into place, use the roof truss location markings to snap a chalk line onto the insulation from one side to the other. Depending upon your location's wind expectations, use a minimum of six up to sixteen screws and plates per panel. Place the first fastener in near the center of the board. Then install the remaining boards.
3.4 IMPORTANT NOTICE: Some manufacturers recommend loose insulation be placed inside any airspace existing below the roof deck and the top of the ceiling insulation. This involves making a 10" square opening between each roof truss along the ridge. Then blow insulation to fill each cavity. Close the opening with a larger square of sheet metal from the coil. Fasten with screws. An alternate approach is to access the airspace through an opening cut at each end. Use a flexible hose to place and distribute the insulation fill. Consult the manufacturer for further information.
4) Membrane Installation
4.1 RoofWrap rubber membrane is supplied in a single, seamless sheet rolled onto a core. It is folded once across its width in order to make the total shipping width 10'. One roll covers a single wide and two rolls for a double wide. The 10' aluminum Termination Bars are placed within the core. To place the membrane onto the roof, start by staging the roll within several feet of, and parallel to, one end of the building. Place a two-inch steel bar (or equivalent) through the core and suspend the roll between two supports, such as sawhorses. Unroll the membrane into a flat stack (accordion style) at the base of the building's end, preferably onto a ground cover. Once unrolled, tie a rope onto each corner of membrane end at the top of the pile. Two ladders are placed near the corners from the end side. Two installers take the ropes and carry the leading end up to the roof. A third installer can assist moving the membrane off the pile. Pull the entire membrane onto the roof. Be sure that the roof edge is protected and free of anything that will damage the membrane as it passes over it. Leave the roll in its folded state, just as it comes off the core. When pulling the folded roll out across the roof, keep the unfolded edge approximately 6" over the roof edge. Exercise caution when pulling the membrane over the taped protrusions so as not to snag or otherwise damage the membrane. Once pulled to the full length of the roof, assure that each end has equal overhang of excess membrane. Now unfold the roll to cover the rest of the roof. There should be an overhang of 6" over each length side and 12" over each end side. One way to adjust the positioning of the membrane is to vigorously flap a corner or edge to entrap air under the membrane. With enough of an air cushion, the membrane can be "floated" into the desired position. Using a soft push broom from the middle to the exterior edges is also helpful to eliminate air pockets or wrinkles. Allow the sheet to relax for 30 minutes. If windy conditions exist, temporarily secure with spring clips, sandbags or other means that will not damage the membrane.
4.2 For roof designs that involve changing slopes, Roofwrap RMS Tape needs to be installed with RoofWrap Barbed Seam Plates and screws to the existing roof deck at each roof slope/angle change. The loose laid and in place membrane must be evenly pulled back onto itself far enough to expose the (first) roof slope angle change. The RMS Tape should be loose laid directly on or adjacent to the line of angle change. The non-taped half will be where the attachment plates and screws will be placed. This half needs to placed onto a level surface. The taped half may be on a non-level surface, but level is preferred. Unroll the RMS Tape and allow it to relax. Attach it every 6" as marked. Next, feed the pulled back membrane so that it is in line with the RMS Tape. Determine where the bottom side of the membrane will contact the taped portion of the RMS Tape. Prime that location with Tape Primer. Once dry, remove the release paper on the RMS Strip. Now uniformly feed the membrane over the RMS Tape. Use the hand held roller to secure the membrane to the tape. Continue in the same manner if there are more angle changes.
If there is no Evaporative (Swamp) Cooler on the roof, skip to Section 4.4.
4.3 If the roof has a swamp cooler, there are two possible scenarios. The first is that the cooler is simply placed onto the roof over unattached sleepers. In that case, raise the unit and slide the membrane under the sleepers. You will have to slit the roof membrane in a straight line to the closest edge in order to allow for through roof conduit. The slit will be sealed with Cured Cover Tape. The second would be that the cooler is placed onto a fixed, four-sided, raised curb. In that case, unfold the membrane to the cooler's first encountered edge. Install RMS Tape around the base of the cooler. RMS Tape can be installed with the non-taped side on the roof deck or vertical curb - whichever has the best substrate to receive the screws with 2" Barbed Seam Plates. RMS Tape is affixed by installing the provided screws and Seam Plates every 12" into the non-taped side. The taped side will eventually adhere to the bottom of the membrane. Predetermine where that area will be on the underside of the membrane. Prime it with Tape Primer. Allow to dry. Remove the release paper on the RMS Tape and manually press the membrane into the tape. Use the hand held roller to secure properly. If square or rectangular shaped, determine the maximum length the membrane can extend up from the roof onto the cooler's side or up under its flashing. Increase that measurement by two inches just to make sure adequate membrane is retained. Carefully cut the membrane evenly along the full side of the cooler. Do the same measurement and cut for the remaining three sides. If the cooler is round, cut the membrane opening so all edges are circular and even and will extend well up the cooler. The resultant opening should be large enough to stretch over the top of the cooler to the roof level. Adhere the membrane at the cooler's base with RMS Tape, cut at intervals into the 3" non-taped portion, in order to allow placement around the round unit. Use Tape Primer on membrane where it will meet the tape's adhesive. If possible, secure the top of the membrane with Termination Bar and caulk. There are many types and designs of swamp coolers. If the style of the cooler will not allow the membrane to be placed over it, follow the same procedure plus make a straight cut of the membrane from the midpoint of the side to the closest structure edge. By opening up the membrane with this cut, the membrane can be wrapped around the unit. The straight cut will have to be sealed with Cover Tape. Any cooler conduit that needs to pass through the membrane must be flashed with Uncured Cover Tape or a Retrofit Pipe Boot. Roofs that have a power line pole mounted to the roof will need to treat its fitting similar to the swamp cooler and side cut. Flash the pole with a Retrofit Pipe Boot.
4.4 At this time, identify the locations of the cut protrusion plumbing vent pipes. With small, sharp scissors, cut a round hole where the membrane is centered over the pipe. The hole must be no more than one-third the diameter of the outside circumference of the pipe. Make the hole as even and as circular as possible. Now, slip the membrane all the way down the pipe. A little dishwashing liquid on the pipe may assist. Remove the duct tape. You will notice that the tight fitting membrane around the pipe extends up the pipe. Peel back the top edge down to about 1" from the roof deck. At that point, apply Lap Caulk onto and around the pipe and replace the folded back membrane.
4.5 Next, install the supplied Plumbing Vent Flashing Caps over the small plumbing pipes. First, prepare the membrane surface with Tape Primer approximately 2" out from the pipe. Also prime the underside of the cap's base flange. Allow both to dry. Place one layer of RoofWrap Caulk Tape onto the vent cap's base underside's extreme outside flange edge. Firmly press into place. Next, place and press the cap base into final position on the membrane centered over the pipe. Screw into place through the pre-punched holes with the supplied grommet screws so that the cap's base imbeds into the Caulk Tape. Do not over sink the screws. Carefully install supplied lap caulk around the perimeter edge of the cap base. Do not trowel, as it is self-leveling. Bolt the top of the cap to the base.
4.6 Now install the Bathroom and Kitchen Vent Hoods. Place the hoods over the anticipated final location. Mark the perimeter with the erasable marker. Remove the flashing hood. Apply Tape Primer to the outside perimeter edge area of the flanges' underside. Also primer the membrane where the flanges' perimeters were marked. Once dry, press one strip of 3/4" Caulk Tape to the extreme outside perimeter edge of the flanges' underside. Place the respective unit into its permanent position over the opening so that its extension below the flange securely connects with the exhaust duct. Use the supplied zip tie for the bathroom flexible duct.
Once in place, use the supplied grommet screws to affix the flanges. Caulk the perimeter edge with Lap Caulk.
4.7 Install any remaining vents, protrusions or stacks.
5) Perimeter Termination
5.1 The final appearance of the roof perimeter depends upon maintaining equal tension on the membrane while installing the Termination Bar completely around the roof's edge. Do not stretch the membrane; just keep it taut enough to maintain uniform appearance. On non-insulated roofs and before installing the membrane, a cleaner, angular perimeter edge appearance can be achieved by mechanically attaching a 4" X 4", 26 gauge "L" metal over the existing edge transition. Install the Termination Bar starting first in the middle of the side and working towards each end. Place the bar over the membrane below the any existing "J Channel" or at least down the side enough to assure fastening to solid wood. The J Channel may be hammered flat before covering with the membrane. If preferable, new J Channel may also be installed in lieu of the supplied Termination Bar. Contact us for further information if this is a considered option.
5.2 Install the Termination Bar starting in the middle of the side and working towards each end. Place the bar over the membrane below any existing J Channel or, at least, down the side far enough to assure fastening into solid wood. The J Channel may be hammered flat before covering with the membrane. Hold the edge of the membrane down with some tension and install the first screw into the bar. This may take two installers working together. Continue the length of the roof edge repeating this procedure while watching for uniform appearance at the area just above the bar. If it appears too loose or too full, simply hold the bar and gently pull on the membrane until taut. Do not fasten the last 12" of the bar near each corner of the structure until both sides and ends are terminated. Complete both sides before starting the ends. To terminate the ends, start in the center and work towards the corners. Bend or arc the bar as needed to keep a good fit and maintain desired look. If the ends have J Channels, hammer them flat and install below. The membrane should extend down equal to or just below where the existing roof terminated. At the corners, either cut the bars to match or bend the side's bar around the corner onto the end and align with its bar. The excess membrane at each corner should be neatly folded back onto itself on the end side as the corner bar is attached. After the bar is installed, carefully trim with a razor knife any membrane material extending below the bar. Do not cut into the siding.
5.3 Inspect the roof to make sure all work is completed. Remove any debris from the membrane.