Roof membrane replacement-need info

[BiigDaddy]

Fulltilt, the prep alone on this project is incredibly impressive! I'll join the crowd who are watching this thread with anticipation...

[fulltilt]

Hi Everyone
We purchased this 2008 model last Fall, it required lots of TLC & both my wife & I wanted to personalize it…make it our own, so to speak. It is our 4th - 5th wheel over the past 9 years, although we have had newer ones we specifically sourced this project. We have not used this trailer yet, but have chosen to redo everything, & then begin travelling again next year. So I have been jumping back & forth from inside to outside, based on weather !
The weatherman gave me a “thumbs up” for 10 days of dry forecast, so I removed the two aircons, 1 hour later, wind changed direction, black clouds arrived, & the skies opened up ! I managed to screw down plywood over the openings & temporarily water proof with “Tuck Tape” to the EPDM membrane. The first picture shows 2 small circles in the membrane under what was the 15K rear air, those circles were cuts in the membrane from the compressor mounting bolt heads in the second picture. Ignore the OSB plywood, that is the platform that I placed both AC’s on. After removal of the EPDM membrane in the 3rd pic, you can see the rust marks of the bolt heads embedded in the roof substrate ! I checked the torque of the bolts, expecting them to be overtightened, but they were not, came off with the slight touch of a nut driver. I have new gasketing material as I believe the foam crushed over time, with the concentrated weight of the compressor. I am going to look at different bolts or grind the heads down on the existing, plus I am thinking that shimming may help to prevent a reoccurrence.
The 4th picture shows one of 2 mushroom attic vents removed. I am confident that they are not factory installed, firstly because they have been mounted near the roof edge at a distance that would be comfortable for someone working off a ladder, whom may have had issues going up on the roof. Secondly being near the roof edge, & the thinnest part of the roof trusses, would not allow good air change. Thirdly, when the holes were drilled, they never cut through the aluminized bubble layer that is installed to raise the roof insulation “R” Factor by R7…in essence both vents were non-functioning. I will be reinstalling 1 replacement mushroom intake vent at the peak & 2 solar powered vent extractors at each end of the roof.

[fulltilt]

Hi Everyone
In the first picture, I glued down some test pieces with the Dicor 901B/A EPDM adhesive…I wanted to see over a few days whether there would be a reaction with the old adhesive. I spoke directly with Dicor & they advised me that the 901 adhesive needs new plywood substrate in order to absorb the water based solvents in the glue, previous adhesive would prevent this process. The old adhesive stays tacky, so sanding is out of the question, adding a second layer of plywood is what I will do.
The 2nd & 3rd pics show the style of transition molding that our rig uses between the fiberglass caps & the roof/sidewalls. I am considering on going to one of the other styles, as they will permit me to adequately seal the screw heads, once the molding is installed. There is no physical way of sealing the screw heads on our style of molding. I have observed multiple areas of the rig fasteners where water has gotten under the screw heads, been trapped there & eaten the screw threads away, weakening the bond. The 2nd pic shows the membrane “under” the front cap, I am anticipating some difficulty in rotating the cap forward at the top, to allow removal of the membrane, & providing the additional clearance for another layer of plywood…I may have to create a knife edge on the ply. The rear cap to my surprise has the membrane also under, this conflicts with all my research, & basic physics, during rainy weather & travelling down the road, the preference would be to have the membrane on top of the rear cap, to prevent water from being driven under the cap in case of a crack forming in the “self levelling sealant”. I intend to try to do the “on top” method at the rear !
The 4th pic also shows that the factory used duct tape at the seams to prevent chafing, this was relatively successful, but I will be using a “glue impregnated” felt tape instead.

[fulltilt]

Hi Everyone
The first picture shows the screws that I have chosen through my research. The “phosphate coated”[black] are a dual thread deck screw by “Dura-Grip”, they 1 ¼”. Dual thread being both fine thread for holding into the metal roof trusses, then the coarse thread for holding in the 2 layers of wood [3/8” & ¼” ply], they utilize a needle point for self drilling into the truss. The “Cad Plated” screw is designed for “snap lock” metal roofing, it has a 1/2” diameter, very flat head with coarse wood threads, I have chosen to use this screw for securing the rolled stainless steel edge transition from the roof to the sidewalls…I will eliminate the staples. The stainless steel does prevent the staples from pulling through, but it has such spring tension to it, that it pulls the staples out ! I will then cover the new fasteners with the “felt tape”.
In the 1st picture shows the Dicor Adhesive impregnated felt tape [CS200B-1], it is 100% water proof, sticks to anything, wood or metal & is reasonably priced in comparison to other products out there. I spoke with “Gorilla Brands”, & they weren’t confident that their product would react with the 901B/A adhesive. They suggested “trial & error” ! I attempted to contact “Eternabond”, but received no replies.
The 3rd pic shows the plywood I am using, it is 100% hardwood, but of more importance for me is that it is guaranteed to have “ 0 Voids”. The lack of voids was all the reason I needed. My existing roof substrate is 3/8” Lauan in decent condition, but it has these voids that do cause flexing, especially along the edges where the roof transitions to the walls. Our plywood supplier tells me that they sell a lot of it to the RV Centers, in particular the Keystone dealer here. The 2nd pic shows my adhesive of choice, I will use a “v-notched” trowel to evenly spread it out on the first layer of plywood.
The 4th picture shows water staining from a “staple” pinhole. I believe it was a fairly recent infiltration as the wood is still solid, there was no interior staining, & believe it or not, the duct tape held in that area…when we brought the trailer home in the fall after the purchase, I put a glob of self levelling over the hole, & we tarped the unit.

[fulltilt]

Hi Everyone
The 2nd & 3rd pictures put into context why I built the frame under the nose in the 1st picture. I also hope that you will understand that I am one pair of hands so everything that I have done so far is to facilitate doing this job alone. In the 3rd pic, I bent up a “hook”, if you will, from some scrap metal & slipped it over the edge of the cap, & merely pulled the cap forward using the scaffold railing, tied it off, this new position gives me full access to fit the membrane under. In an earlier post, I mentioned that the membrane was fitted under the rear cap as opposed to being placed on top, & my reasons for wanting to see it done that way…I will now have to build a platform under the rear cap, with a couple of props, to allow it’s rotation.
So today I rotated the top of the fiberglass nose off the roof, exposing the membrane. Notably, Dicor recommends, as do others, to add butyl tape top & bottom of membrane before installing cap…there was nothing ! I will have to decide as to whether I do what they say, or do what they do !? There is no indication of moisture ever in this area over the 11 years. A full 6” of membrane was under the cap, 3” of it was downturned, pulling it out would be out of the question, & tucking the new membrane back under without shifting the cap would not end in a satisfactory result.
Also today, I removed several hundred staples along the top only of the stainless steel, rolled transition strips, along both sides. Tomorrow I will have to take a “hammer & dolly” to try & reflatten the metal. Once I cut, slip, & fasten the new plywood under each side strip, I will then remove the staples on the outside walls, replacing them with the flat screws.
I cut all 3 plumbing vents flush with the existing roof substrate, & I triangulated their location on the scaffold railings. I did this for 2 reasons, one I don’t want to spend time measuring hole locations on the new plywood & two, when it comes time to lay the membrane out, I don’t want anything to stretch the membrane during the gluing process. I can plunge my router around the vents, the vent caps themselves handle up to 2” pipe, so the 1.5” coupling will easily fit underneath. The larger openings in the roof will be easily located from inside the rig, drill a hole from under & then buzz the router from up top. I don’t anticipate an issue with this plan, I am more concerned about getting any bubbles from under the membrane out.

[psomers]

Really well documented. Looks like you did your planning. I like doing that kind of work and would have loved to have given you some free labor.
In picture from post #23 it looks like you have camper neighbor across street. He didn't want to help?

[psomers]

Really well documented. Looks like you did your planning. I like doing that kind of work and would have loved to have given you some free labor.
In picture from post #23 it looks like you have camper neighbor across street. He didn't want to help?
Glad to see you replaced those staples.

[fulltilt]

Thank you...the fellow across the street is a friend & neighbor, we have travelled together, he along with several others do offer to help, but I decline, I could never forgive myself if he lost his footing & got hurt. I am considering on asking for help from two considerably younger neighbors, or my kids to help apply the adhesive & lay the membrane when it comes time !

[fulltilt]

Hi Everyone
This is the top of the wall in picture #1, looking down on it, where under the “rolled stainless steel sheet metal” transitions the roof membrane to the top of the exterior of the wall. I have removed the metal & I am going to try & straighten it out, the staples & the shear number used made a mess of the metal. There was zero insulation in the cavities above the wall top plate under the sheet metal [the corner]. What I found on our rig was that the roof sheathing was 1” too short, down one complete side, as seen in picture #1, & over hanged on the other side. If you were to walk on the roof near the edge, the sheathing would deflect, under the EPDM membrane until it came into contact with the top of the aluminum angle underneath in picture #2, of course where the sheathing is too short, nothing stops it, either way, over time, the staples will pop. Please note the 3/8” gap between the underside of the roof sheathing & the aluminum angle that attaches the roof trusses to the wall top. Note the wire, in picture #2, rubs on the aluminum angle, there are 5 electrical feeds on both sides of the trailer, done this way. Today, I purchased 16’ of 1.5”x1.5”x1/8” angle aluminum extrusion, & intend to cut 3” pieces & will attach one into each space between each roof truss to prevent the roof sheathing from ever deflecting again. I will put a protective sheath over each wire pair, & I know the brackets will prevent the wire from being pinched. My intention before I reinstall the rolled metal, will be to insulate the cavities on both sides of the trailer.
Yesterday, I managed to lay down 3 sheets of the new roof ply, starting at the front. I staggered my joints to the next truss [16”], & what I found was that the trusses did not line up after that, using the 48” width, I have to cut each sheet narrower, I didn’t see that one coming ! I assume all the roof openings are the cause of that.

[mazboy]

After seeing what had to be done I'd either buy a another trailer, quit rving or pay for someone to do it for me:-)

[fulltilt]

Haha...Thank you Mazboy for reading my post, I quit every day about 2pm, & feel like someone just dragged me through a knot hole backwards !

[psomers]

Just curious, what year and model are you working on Fulltilt? The starter of this thread was Jimongee and his was 2006 2955. Didn't see where you posted this information.
Doing very good job. How much are you charging for labor?

[fulltilt]

Hi psomers
This is a 08 Grand Junction...when I joined the Forum we owned a 2012 Montana, before that a 2007 Montana, & before that an 06 Cougar, I worked on all of them extensively. I have remained a member for that reason, but when Jimongee posted, I responded, next thing I know people wanted to follow, & asked me to post pictures.

[fulltilt]

I meant to thank you for your kind words. I am hoping that by sharing this replacement, that it helps others to make their own decisions whether they wish to tackle it or not. For me the write up & pictures take almost as long as the work ! Today I hope to finish the roof sheathing & experiment with the extrusion brackets that I am planning to install.

[WeBeFulltime]

You have really got your act together!

[fulltilt]

Hi Everyone
Thank you to WeBeFulltime !
Today I laid 3.5 sheets of roof sheathing, & experimented with the aluminum angle extrusion to support the roof edges under the rolled metal. I am going to make the brackets 4” & place one bracket roughly centered between each two trusses. In the second picture, you can see 2 brackets, on the right, I used self drilling screws & a dab of self leveling caulk over each screw head to prevent loosening over time, but during the course of installing this, it occurred to me that rivets would be a better choice [ 3rd picture], hence that is what I will do. I will remove the first bracket & install rivets in place of those screws. I haven’t installed the additional layer of sheathing in this area yet, but I must tell you, stepping on the roof edge now is absolutely solid. I placed an anti chafing sleeve over the wire feed which is next to the bracket on the right, between that & the bracket, I do not anticipate any issues going forward with the wire. I will do this with each wire pair. I realize this may take me a few days to complete, about 48 brackets involved but at the end of the day I will feel better for it.
Just a short note on the sheathing in the 1st picture…I am very pleased with the product, it has stiffened the roof up more than I expected & with the hardwood core & zero voids, I can screw through it within ½” of the edge without ply squeeze out.

[fulltilt]

Hi Everyone
I haven’t been working on the roof replacement for about 6 days, other things taking priority ! I started back on it a few days ago & this is where I’m at now. I have completed the additional layer of roof sheathing, but as you can see I haven’t routered the roof penetrations out yet, instead I am working now on the rolled metal transition from the roof edge to the top of the wall. I am also filling the void with insulation which the manufacturer had left out…it would have been hard enough in a closed factory, but outside you need as many arms as an octopus, particularly when even the lightest breeze rears it’s head ! I dabbed contact cement on in several places on the pink wool & corresponding spots on the wall top, seems to work well, now one pair of hands is adequate !

[fulltilt]

Hi Everyone
So now to the roof/wall transitions. I cut 48 pieces of aluminum angle 4” long, filed, & drilled them [pic #1]. I installed them using rivets, & at each bracket location you can see that I drove in 2 - #12 screws through the wall top angle to add torsional stiffness. These brackets [pic #2] have added a noticeable improvement in roof firmness, little to no roof deflection now. Each bracket is approximately centered between each pair of roof trusses. For perspective, to make the brackets & install them, it took about 6 hours, but being able to lay on a platform for the install, is a lot quicker than using a step ladder.
In picture # 3, I have stacked a couple of 2”x10” on saw horses to hammer out the strips which are in 10’ lengths, 5 for each side of the trailer, overlapped. The manufacturer used staples, the quantity was off the chart, & the damage they did to the metal was brutal. I hammered the dimples out, then with the clean up wheel on my hand grinder I smoothed them out to within reason. In pic #4, please note the small “hook” above the #5, that is from a staple & there are many hooks like that, all looking to puncture the EPDM membrane! They were shot in, many along the edge like the example, but in addition, the metal screws used by the manufacturer, self drilled through the metal, with the same result, small hooks about many of them… so in the 3rd picture, I used my hand punch, I punched ¼” holes, on 6” centers for fastening with screws the top, & 12” centers along the bottom where the “gutter extrusion” will eventually cover. By punching the holes larger than the screw shanks, it resulted in zero “hooks”. The factory installed duct tape over these “hooks”, which worked for the most part, except on one. I am hoping that the adhesive impregnated felt tape will achieve a higher level of protection.
Tomorrow, I plan to continue to insulate the voids under the metal strips, & then install them.

[fulltilt]

Hi Everyone
I completed the sheathing & routered out all the roof penetrations, then applied the felt tape at all seams, as per Dicors instructions. I laid the membrane down for a day or so, to allow it to “relax”. My neighbor came over at first light this morning, & helped me apply the adhesive & lay the EPDM down. The temperature was in the 60’s & no wind ! The work this morning was just under 2 hours…we followed Dicors recommended installation instructions for the adhesive & EPDM membrane, the job went far better than I expected! I used the window squeegee to pull the air out from under the membrane once down, the roller sleeve is a Wooster 9”x 1/8” nap designed specifically for adhesive application, Dicor wants the adhesive wet when laying the membrane, so we folded the membrane in half, front to back, rolled on the adhesive on the wood only, then lifted the membrane across. The adhesive remains “white in colour” until it flashes [dries] so this helps a great deal in knowing your time! In the next day or two, I will begin putting everything back on the roof…I have purchased all vents, skylight, etc., new & before I reinstall the AC’s I will take a close look at the evap’s & condensers for dirt buildup.

[bw2]

Is there a reason why not place the new dicor epdm roof over the existing roof? Glue the new to the old?