What coating or paint to use on the roof?

[Patricia D.]

The roof on my Ventura was covered with a thick coating of tar. Most of it has been removed now and I am thinking about the next step.
There are lots of cracks, bull's eye circles and small holes (pinhole to about #8 screw size).
Now that the tar has been removed, I can see daylight like stars in the ceiling.
I had put several coats of resin inside on the ceiling to seal the tiny holes but somehow had not seen the larger holes.
Now I am not sure how to proceed or what product to use once I have thoroughly cleaned the roof of all tar residue.
Any suggestions?

[k corbin]

Originally Posted by Patricia D.

The roof on my Ventura was covered with a thick coating of tar. Most of it has been removed now and I am thinking about the next step.
There are lots of cracks, bull's eye circles and small holes (pinhole to about #8 screw size).
Now that the tar has been removed, I can see daylight like stars in the ceiling.
I had put several coats of resin inside on the ceiling to seal the tiny holes but somehow had not seen the larger holes.
Now I am not sure how to proceed or what product to use once I have thoroughly cleaned the roof of all tar residue.
Any suggestions?

Microballoons...I was just using this stuff today to level and fair the exterior surface of the shell after repairing some large holes in the shell where I wanted to have an absolutely level surface with an invisible repaired area. Your problem of pin holes is what they are discussing in this video. But I personally would first fill those larger #8 holes with epoxy putty then after sanding them flush do a once over with the microballoon putty to catch any small surface irregularity. Only make small batches when the weather is warm or it will set up too fast on you. Or use the slow speed resin instead of the thicker Flag resin.

https://www.youtube.com/watch?v=ZSq0sHn_OLg

[Patricia D.]

Thanks. My problem is where to get the microballoons. I have yet to see them in stores in Winnipeg.
Any suggestions for a roof coating once I have the filling done?

[k corbin]

Originally Posted by Patricia D.

Thanks. My problem is where to get the microballoons. I have yet to see them in stores in Winnipeg.

Any suggestions for a roof coating once I have the filling done?

You will use a primer suitable for use with fiberglass then get a quart of marine boat paint and roll it on. Or you can look for advice here about paints from the automotive industry. Another choice is to prepare the surface, hire an autobody repair facility to put the paint on for you. They will charge for the paint unless you bring your own, if you want them to use marine paint take it with you. The price will be an hourly rate plus fees for materials such as supplies for masking, thinners, supplies for cleanup and likely also a hazardous materials disposal fee. They do have to cover those extra cost beyond labor. Try the cash discount routine, it is a small job and you never know but you might get one. That is what I am doing to get the red marine paint sprayed on the upper half of my Campster since I don't have a good place or the equipment to spray it myself. It is a shop referred to me by a friend who has used it in the past and they said they will do it for their hourly rate. I will take it in with the primer already on it since I was able to get it done myself with spray cans. The primer dries quickly but the red takes a lot of hours and too much debris would get into it if I tried to paint it outdoors. We all have to make decisions on what we can and can't do ourselves.

For supplies in Winnipeg try contacting Cargo East Marine Supply, they are in Winnepeg. They may sell the epoxy, the micro balloons and other fillers for epoxy and also the paint and primer. If not they might be able to refer you to a local supplier for these items. But of course you can always place an online order, these things are nothing exotic even though not a common hardware store item.

[Patricia D.]

Thanks for the information. I was under the impression that there are special products for the roof, not just primer and paint. I have to paint the whole trailer and if I start with the roof, it will give me a chance to get a feel for marine paint before I do the rest.

[Jack Walter]

Micro balloons can be bought at aircraft supply stores like Aircraft Spruce. A friend of mine is building an airplane and he is suing micro balloons to fair out his wings.

I'm thinking of painting my trailer with Monstaliner. I've seen some 4wd trucks coated with it and its very durable and available in a bunch of colors.

[MCDenny]

Google "Marine Epoxy" Any internet seller will have the stuff you need.

[k corbin]

Originally Posted by Patricia D.

Thanks for the information. I was under the impression that there are special products for the roof, not just primer and paint. I have to paint the whole trailer and if I start with the roof, it will give me a chance to get a feel for marine paint before I do the rest.

You don't need special products for the roof when you have a fiberglass roof. Quit looking at those products, they are the wrong thing to do with your roof. All that aggressive marketing of super duper roof fix products and people in forums that don't know what is what is getting you confused on what to do. Those products are for thin metal roofs that get pin holes that penetrate all the way through the metal due to metal corrosion.

As to the holes you are seeing.... Do they actually penetrate all the way through the shell or are you just seeing dots of light where the gel coat has been lost? Anywhere the gel coat is lost you will see light coming through the shell but that does not mean there is a leak happening. I strongly suspect that what you are seeing is not a bunch of actual holes that penetrate through the shell but instead they are areas where the gel coat is missing. A pin hole of light showing through on the inside is not a huge issue as it is not causing a leak, gel coat touch up or primer and paint on the pin dot and that problem is fixed. But a field of stars of lots of pin holes over a lot of the roof areas is an indication your gel coat on the roof area has gotten too thin and it is time to add more gel coat or paint to protect the fiberglass resin from UV damage. Since you were removing that tar like coating it is very likely some of the get coat went with it.

If those were just dots of light from missing gel coat adding that resin on the inside of the shell did not do anything to fix this issue since there never was a hole going all the way through. So for anyone else reading this thread realize you do need to figure out if the issue is a through hole or loss of gel coat.

An actual hole in the shell that penetrates all the way through does create water damage issues but small holes can be easily filled with thick epoxy (put tape against the opposite side of shell as a backer) then sand the outside surface of the tiny spot smooth before priming and painting. Otherwise if you did not want to paint you could get a gel coat touch up kit and use that instead of paint.

[Patricia D.]

Once the tar was all removed and the roof was washed I was able to see the extent of the sagging in certain areas.
There are large sunken areas about 12" and 1" deep in a continuous series of hills and valleys across about 1/4 of the roof.
I suspect that there was a heavy load from snow, a tree, someone kneeling on the roof or ? at some point.
I have put in additional roof support inside and have raised the shell as much as I can with blocking. I have done as much as I can inside and the problem is less than it was and the roof feels much stronger.

K.Corbin, to answer your questions, there are definitely some holes. It became obvious which were holes and which were not once I was doing the tar. If I found tar inside on the ceiling, I knew I had a hole. There are several cracks as well. I feel confident in fixing them. I have done quite a bit of patching already.
I was able to find the microballoons and am now thinking about how to proceed.

The picture shows the roof from the inside and you can see the cracks etc. in the gelcoat, I presume.
The issues are:
1) the tar that is still in the cracks. If I clean the roof thoroughly and use a solvent to get as much tar residue off as possible, will any tar in the cracks interfere with setting up of the epoxy/microballoon mix?
2) the fact that the whole roof is covered in these cracks and holes (holes will be sealed and sanded) means that I would like to use a thinner mix and coat the whole surface. Is this misguided?
3) the above mentioned "potholes" in one area seem too deep to me to be filled completely (cover about 12 square feet). I am thinking of using a thicker (peanut butter) mix and fill as much as possible then sand smooth and overcoat with the thinner layer. Again, misguided?
Thanks.

[Borden]

The advise from K Corbin above is solid with our toys

Got a boat builder to help me learn how to repair the gelcoat cracks and such, used resin, fiberglass and gelcoat and will add a single coat of sprayed gelcoat over the final fix to make it real even colour also replacing all the rivets with new closed end pop rivets of same size as originals the closed end type pop rivets i was told the can hold 500 psi.

Learning to think boat with our fiberglass gems