Zip board and Raptor Liner for new roof?

[HaulinBass02]

Been a long while since I’ve been on here but our 2008 Trail Lite is about to need a roof. I’ve made it last about as long as I can but am going to have to do something later this year. A friend of ours had their rubber roof removed and the roof coated with a bedliner type material.
I’m getting ready to buy Raptor Liner for a DIY spray in liner for my truck and figured, this should work for a roof material as well. It bonds to anything including wood, especially if epoxy primes first.
I need to pull off the roof decking to do some HVAC duct mods and run some wire circuits for the vent fans. I’m thinking that going back with 7/16” green Zip Board will help as it is weatherproof and seals very well. Also acts as a type of radiant barrier.
Seal all the vents and then Raptor line making it a seamless roof.
Anyone see any potential issues with this?

[sprintstream]

I think the spray on bed liner material would be just the ticket if, as mentioned, everything is properly protected. I've just had my truck done and noticed extra UV resistance was available as were additional colors. Done right I see no issue here except for repairs around roof piercings and that too can be handled if planned for.

[MrWizard]

"I would speculate that it hasn't ever been used simply due to the fact that it would involve more labor man hours, cost more and slow down production."

Bingo !# we have a winner

Lot's of RVs have fiberglass roofs, they hold up very well

Other members have done similar projects with good success

[HaulinBass02]

Patperry2766 I can totally agree with this. I think it is a viable roof alternative for someone to DIY. I am willing to take the “bullet” and do this especially since our camper is paid for and I have no reason to go any other way. I really want the benefit (hopeful) of the reflectix insulation to cut heat out of the camper. There is so much heat soak thru with RVs because of the lack of sufficient insulation in the ceiling. I see the main benefit to all of this with that. I will keep everyone updated.

[patperry2766]

I would speculate that it hasn't ever been used simply due to the fact that it would involve more labor man hours, cost more and slow down production.

The time involved in taping everything off to prevent overspray but probably more importantly is that it would force the manufacturers to build a better roof. The spray on liner wouldn't hide roof imperfections and shoddy workmanship near as easily as the current roofing options available today. Many years ago, I had a boat that I ripped up the carpet and had to redo the decking because of a few soft sport in the floor. It was labor intensive on my part because I took the time and effort to make sure everything was done right and properly installed BEFORE I had it sprayed.

It would slow production down because of the prep work involved, actual application of the products plus time for it to dry. It would fly in the face of modern RV construction of building them as fast as possible and as cheap as possible.

[HaulinBass02]

theoldwizard1 wrote:

Thermoguy wrote:
Interesting idea. Rubber roofing always seems to be the trouble point for RV's. Any idea why RV manufacturers don't use spray on bed liners for roofs?

My guess is that it does not hold up well in the sun.

For a couple hundred more dollars they could probably install commercial grade TPO.

I’m really not sure how you can say that. Spray in bedliner has been around for a long time now. Properly applied, it will last a lot longer than any rubber and probably a TPO roof. I’ve never ever had one crack or peel in any truck bed I’ve had sprayed and I am not easy on them. They are UV resistant to fading and cracking. I would much rather have that on my roof than anything else. All that I’ve read about TPO is that I would not want it on my roof here in Texas.

[theoldwizard1]

Thermoguy wrote:
Interesting idea. Rubber roofing always seems to be the trouble point for RV's. Any idea why RV manufacturers don't use spray on bed liners for roofs?

My guess is that it does not hold up well in the sun.

For a couple hundred more dollars they could probably install commercial grade TPO.

[Thermoguy]

Interesting idea. Rubber roofing always seems to be the trouble point for RV's. Any idea why RV manufacturers don't use spray on bed liners for roofs? Too Expensive? Too heavy? Some other reason? I'll be curious to see how this works out.

[gbopp]

The Reflectix will do the job. Use aluminum tape so it creates an air tight barrier.
I think spraying the liner directly on the plywood will give a better bond than applying it to Zip sheathing.
I would use plywood rather than OSB. Plywood can survive a small leak, OSB will absorb water, expand and turn to mush.

Keep us updated on your roof project.

[HaulinBass02]

gbopp wrote:
With the Zip you're probably adding a little more weight to the roof.
Are there any curves or bends the Zip will need to follow? I don't think Zip is very flexible. If the roof is flat, no problem.

I wouldn't expect it to act as a radiant barrier. It's not reflective and for a radiant barrier you need an air space above the barrier.

Could you use the Zip with insulation attached? It would raise the height of the roof but, give you some insulation.

I'm not familiar with the spray on liners you plan to use on the roof.
Your plan should work, assuming the spray does not react with the Zip coating and tape.

Roof does have a curve to it but it is not much. Maybe 1” higher in center than the edges. I will obviously have to go look at the ZIP board and see if it will flex at all.

My other thought was to install the silver Reflectix bubble insulation on the bottom side of the arched “rafter” giving the airspace needed or maybe under the decking itself sandwiching it. It wouldn’t causing the roof to be noticeably taller as it would compact down over the rafter pretty easily. I would just use standard 3/8” OSB or plywood like is there now and then the Raptor Liner over it.

Raptor Liner material is in-between Linex and Rhino in texture and feel. If it is good for a truck bed or even coating an entire car, I feel confident in its abilities to be used as an RV roof.

[theoldwizard1]

I would never use a product on a roof that is not SPECIFICALLY designed for a roof ! I am not a big fan of EPDM (rubber) roofing. It breaks down too fast in sunlight. IMHO TPO is more durable but you have to use the "commercial" grade (thicker). Seams are hot welded (melted). Roof protrusion require "curbs" cover with TPO and welded to the rest of the roof.

Check this out :RV Roof Education 101

Watch a few video by the same company.

7/16" decking is way overkill. 1/4" is acceptable if you have 16" O.C. rafter. 3/8" would be better.

[gbopp]

With the Zip you're probably adding a little more weight to the roof.
Are there any curves or bends the Zip will need to follow? I don't think Zip is very flexible. If the roof is flat, no problem.

I wouldn't expect it to act as a radiant barrier. It's not reflective and for a radiant barrier you need an air space above the barrier.

Could you use the Zip with insulation attached? It would raise the height of the roof but, give you some insulation.

I'm not familiar with the spray on liners you plan to use on the roof.
Your plan should work, assuming the spray does not react with the Zip coating and tape.