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 unique, distinguishing features.
Install the EPDM membrane in accordance with the appropriate current printed RoofWrap Installation Guide. Installation scenarios not addressed in the Installation Guide should be forwarded to RoofWrap for consultation.
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.
- 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.
- Retrofit Pipe Flashing Kit: A two part, round curb intended to fit around roof penetrations that cannot be disconnected such as a power pole and swamp cooler legs. Kit also includes an adhesive and curb filler sealant.
- Termination Bar: The aluminum bar that, with screws, secures the roof membrane to the perimeter wall fascia and roof deck that has profile angle and level changes.
- 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.
- Caulk Tape: A thick, permanently flexible adhesive tape that serves as a waterproofing gasket between the bottom base of roof pipe flashing hoods and the RoofWrap membrane.
- Hybrid Attached: Using 1' wide strips of plywood or OSB, attached to the existing roof, to serve as a base for adhesive attachment of RoofWrap.
- Water Base Adhesive: A water based acrylic adhesive that is used to adhere RoofWrap providing higher wind resistant exposures.
Recommended Tools and Equipment For Three 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
*Optional 17. Scaffolds - one or two
*Optional 18. Sheet metal coil - 26 gauge minimum
*Optional 19. 2" Nylon or steel handheld roller
*Optional 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, mostly 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. For asphalt shingle roof recovers, staple one layer of 4 mil (min.) poly over entire roof ahead of RoofWrap.
2) Preparation of Roof Pipe Penetrations
2.1 On a mobile home, there can be a furnace stack, one hot water heater stack, one or two small soil pipes (depending upon the number of bathrooms) and an exhaust vent from the kitchen and bathroom. Another penetration 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. NOTE: Roofwrap can supply cap flashings for the kitchen, bathroom and plumbing soil pipes. Roofwrap can also provide sealant tapes for waterproofing the other listed penetrations that, if replaced, are sourced at RV parts, HVAC or plumbing retailers.
2.2 Remove all vent and fan hoods, flashing collars and other pieces so as to allow the membrane to be placed over the opening. The removed covers can be reinstalled, or replaced with new, near the job's completion.
2.3 Soil vents are used above bathrooms to carry plumbing gas exhaust. 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 to protect against damaging the roofing during placement. The Kitchen and Bathroom Fan Vent Flashing Hoods are supplied with an 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.
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 Board and Installation (optional)
(If no additional roof insulation is to be used, skip to Section 4.1)
3.1 RoofWrap does not supply insulation board for economic reasons. Sourcing your insulation from a local building material or roofing supply firm will eliminate the added cost of freight and potential damage.
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'. 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, strength and has no reinforcing 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. EXP boards have a standard 4' x 8' size.
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 and is sold in 4' x 8' boards.
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 an erasable marker or tape on the exterior wall, of both sides, below the point where the membrane will terminate. Do not shorten the vent 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 avoid damage to the unsupported and fragile insulation board corners 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 pipes, 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 compression plates per panel. Place the first fastener in near the center of the board. Set the remaining fasteners evenly distributed across the board. Install the remaining boards in the same fashion.. NOTE: If the roof surface is too uneven, using 4' x 8' boards will result in unacceptable gaps between the board and roof deck. In this case, cutting all the boards to 4' x 4' will minimize this condition.
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 or adequate plywood. Fasten with screws. Use an extended plastic pipe 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. One roll covers a single wide and two rolls for a double wide. The 10' Aluminum Termination Bars attachment strips are usually 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 at this end.. 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 over the edge and 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 either long roof edge. Exercise caution when pulling the membrane over the taped pipes 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 at least 6" over each length side and 12" over each end. 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.
For doublewide roofs, two separate Roofwrap sheets are supplied. Usually one sheet will be slightly wider in order to place the lap just to the side of the ridge. Place both sheets onto roof and center into final position. Overlap the wider sheet 4"-6" over the narrower sheet. Pull back the overlap to expose the top edge of the bottom sheet. On the upper edge, attach the entire length with Roofwrap All-Purpose Termination Bars and screws every 6" oc. Next, prime with Tape Primer at least 4" of the bottom sheet under lap and the same location on the underside lap on the top sheet. Allow to dry to sticky state. Finally, install Roofwrap 3" Seam Tape between the sheets at lap with 1/4" of the tape exposed beyond lap.
See this document for a detail illustration of this application.
Roofwrap designs its systems to meet the wind exposures of your specific locale. We offer low, medium, high and very high exposure attachment methods.
4.2 Hybrid-Adhered Installation over a Porous Surface - Medium, High and Very High Winds
(If your application is using "Low Wind Exposure" application - skip to 4.3)
Elevated wind attachment (Hybrid) applications require preparations before the RoofWrap membrane is placed onto the roof.
For installations in Medium and High Wind regions (as selected during information input on this site's Price Calculator) the installation will use Roofwrap Acrylic Water Base Bonding Adhesive with 1/2" or less thickness strips of OSB sheathing (rough side up) or plywood, cut to 8' x 12" widths and screw attached to the existing roof deck at its roof trusses.
Now, the RoofWrap membrane is been laid into place and allowed to relax. Next, pull the membrane back onto itself, exposing half the old roof with the sheathing strips. Apply the adhesive onto the strips at a coverage rate of 100-125 lineal feet per gallon. When freshly applied, the adhesive should be a light, milky white. Lay the membrane back into place over the wet adhesive as soon as possible. This ensures the wetting of the membrane's bottom surface.
Once this half of the sheet is in place, use a push broom to sweep the surface, keeping a steady pressure with the broom against the surface of the sheet, mating surfaces and eliminating captured air between the membrane and the strip. If the sheet is critically out of intended position, lift the sheet up to the problem location. A reapplication of adhesive is usually necessary.
Repeat the same process for the other half.
See this document for a detail illustration of this application.
Proceed with 5.1 Perimeter Attachment below.
Fully-Adhered Installation over a Porous Surface
Cover the entire roof with 1/2"+/- OSB or plywood. Screw the board to the roof trusses with a minimum of 16 screws per sheet achieving a minimum 1 1/2" penetration into the trusses.
Once the RoofWrap membrane has been positioned and given sufficient time to relax, fold the membrane in half (onto itself) exposing the new substrate surface. Starting at the fold, apply adhesive to substrate deck only. As you proceed with the adhesive, feed the membrane into the wet, white adhesive. Lay the membrane into the wet adhesive as soon as possible. This ensures the wetting of the membrane's bottom surface.
Once this half of the sheet is in place, use a push broom to sweep the surface, keeping a steady pressure with the broom against the surface of the sheet, mating surfaces and eliminating captured air between the membrane and substrate deck. Broom from the interior of the sheet to its outside perimeter. If the sheet is critically out of intended position, lift the sheet up to the problem location. A reapplication of adhesive is usually necessary.
Repeat the procedure for the second half of the sheet.
Proceed with 5.1 Perimeter Attachment below.
1) Traffic over freshly adhered membrane should be minimized. Try to broom out footprints in the adhesive. They will be less visible once the adhesive cures.
2) These three options involve using 1) screws to attach continuous compression bars at the roof's perimeter and/or 2) 12' wide plywood or OSB strips screwed to the existing roof to serve as a base for a Roofwrap adhesive to hold the membrane in place. The holding quality of the system will achieve its greatest ability with the screws placed into the wood truss and perimeter members. The screws proper penetration and the wood's integrity to provide maximum pull out resistance will determine the actual system wind resistance.
(If the roof's side view profile is basically level, skip to Section 4.4)
4.3 For roof designs that involve steep or acute changing slopes, a 8' x 12" wide strip of 1/2"+/- plywood or OSB is installed with screws to the existing roof deck/trusses at each roof slope/angle change with two screws every 12" oc. These strips will serve as the base for the adhesive. The loose laid and in place membrane must be evenly pulled back onto itself far enough to expose the (first) roof slope angle change and the wood strips. Brush or roll Roofwrap Water Based Adhesive onto the 12" wood strip at 100-125 square feet per gallon.
See this document for a detail illustration of this application.
(If there is no Evaporative (Swamp) Cooler on the roof, skip to Section 4.5)
4.4 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 support 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 penetration that cannot be disconnected. The slit will be sealed with Roofwrap Cured Cover Tape.
The second would be that the cooler is placed onto a fixed, four-sided, raised curb. Here, the membrane will be cut to allow it to be placed over the top of the cooler unit and slid down to the roof level. First, unfold the membrane to the cooler's first encountered edge. 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. Next, cut 6" strips of thin plywood or OSB sufficient to extend around the perimeter of the base where it intersects with the roof. Attach the strips with wood screws 6" oc. Brush Roofwrap Water Base Adhesive onto the strips at 125 square feet per gallon. The adhesive should be milky white when freshly installed. Adhere the membrane at the cooler's base with fresh, wet adhesive. Assure full adhesion with a soft broom or manually. If possible, secure the top of the membrane with Roofwrap 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 Roofwrap Cover Tape. Any cooler conduit that needs to pass through the membrane must be flashed with Roofwrap Uncured Cover Tape or a Retrofit Pipe Boot.
4.5 At this time, identify the locations of the cut 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. If possible, peel back the top edge down to about 1" from the roof deck. At that point, apply Roofwrap Caulk onto and around the pipe and replace the folded back membrane.
4.6 Next, install the supplied Plumbing Vent Flashing Caps over the small plumbing pipes. First, clean the Roofwrap surface around the pipe with a non-solvent household spray cleaner and rag. Allow to dry. Place one layer of RoofWrap Caulk Tape onto the vent cap's base underside's outside flange edge trough. 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 screws so that the cap's base imbeds into the Caulk Tape. Do not over sink the screws. Carefully install supplied Roofwrap Caulk around the perimeter edge of the cap base. Bolt the top of the cap to the base.
4.7 Now install the Bathroom and Kitchen Vent Hoods. Place the hoods onto the membrane over the anticipated final location. Mark the perimeter with the erasable marker. Remove the flashing hood. Clean, as before, beyond the marked outside perimeter edge. Once dry, press one strip of Caulk Tape to and within the extreme outside perimeter edge of the flanges' underside. Place the respective hood 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 Caulk.
4.8 Install any remaining vents, penetrations or stacks. If Roofwrap Cover Tape is supplied, prime the area to receive the tape with Tape Primer using the supplied pad. Once dry, remove the release paper from the tape and press into place.
5) Perimeter Termination
Note: If hanging gutters are to be installed, they should be done so before Termination Bar installation. In order to achieve proper runoff into gutters, the RoofWrap should extend sufficiently into the gutter. Depending upon the roof edge's lateral uniformity, a 1" x 4" board can be attached to the drip edge to provide a straight surface. Set the gutter into place with the RoofWrap extending into it. Tack the gutter into place enough to allow Termination Bar installation. Trim the excess RoofWrap below the bar. Finally, install the gutter hangars.
See this document for a detail illustration of this application.
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. There's no need to 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 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. The Termination Bar will be placed over the membrane below the any existing "J Channel" or at least down the side enough to assure fastening to solid wood and covering any water entry points. 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. Hold the edge of the membrane down with light 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 at each corner of the structure. 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 position 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.