Jump to content

Stripping Down A Roof. Eye Opening


Back East Don

Recommended Posts

My RV is the victim of a series of half measure or just misguided repair attempts including a couple by me. Linda sure called it and then some. Found lots of pin holes once I got past the old coats of crap. Front vent and seam look pretty good but there was some old holes in the roof from something.

vent_01.jpg

The pinholes are in various places but the heaviest concentration is where the roof AC once was. All around that vent is pretty much swiss cheese. Some more along the edge trim.

pinholes_04.jpg

I had been using paint thinner to remove the traces of roof coating left behind from scrapping with a heat gun and putty knife then fine wire wheel. The adhesives left from the rubber roof seam tape I used to cover old repairs a few years ago was a complete pain to remove. I found that paint brush cleaner works great at dissolving most of what was up there. Didn't affect the paint as the dissolving action seems to dissipate quickly. I suggest a respirator when working with heavy amounts like I did with paper towels. The first picture was wiped down really cleanly. This next one is what it looks like before the brush cleaner and elbow grease.

roof_02.jpg

Weather is not looking great and I'll be in CA next week on business. Tarp is up for now and if nice at all this weekend, I'll install the vents and repair as much as possible before I head out on Monday.

Link to comment
Share on other sites

wow, I have read about pin holes, good to see them.


I am seriously considering putting a rubber roof on top of mine and getting rid of all the holes except for the vent fan ones. And then wrapping the rubber over the edges and attaching them to the side to resolve seam leaks.


Link to comment
Share on other sites

I've got the liquid EDPM coating to do the top along with the epoxy primer for covering any asphalt based coatings. Instead as I began stripping, I just kept going and so I'll have most of it down to bare paint or in places metal. Primer can only help the adhesion. Sorry for the blue images. I fat fingered one of the filter settings on my phone and engaged a blue filter. Today I picked up some aluminum & pop rivets to patch the big holes with. It is kind of cold and windy out this afternoon with possible showers due. Saturday is so far looking good. Hope to get more done then.

I initially hoped to go with the sheet EDPM but in researching it, the adhesives are not meant to go over the metal roof. They are water based and will not cure properly unless there is a wood underlayment. This would require that I would need to adhere plywood as a base. I then looked at adhesive to bond that to the aluminum roof. What glue was going to adhere to the coatings already up there. Only a couple were rated for metal to wood and I wasn't going to just go only with screws. Then what to do with the edge trim. The roof is now taller and the trim would not fit properly unless I used the thinnest of sheets. I can get 1/8th" sheets but I lose any benefit of reenforcing the roof at all so why bother. And then it is still going to be a tight squeeze as I figure it. Pricing also started to get steep. There are vendors on Ebay but the cheapest was selling by the foot with $16 shipping. That is $16 a foot. Amazon had the best deal at just under $400 with free shipping. The liquid roof is going to come in at about half that even with the primer. I read through the reviews on Amazon for Liquid Roof are pretty positive and there is one from a guy with a toyota MH.

What ever you choose, I recommend doing lots of research first and solving all the possible challenges. This ended up being more work than I wanted but the wife and I have settled on keeping this even if we purchase a larger trailer for longer trips. So I'm much more willing to spend the extra time and money. I just decided the sheet EDPM wasn't for me in the end. If you go with it, I'd love to learn how you conquered the challenges I thought would be beyond me.

Link to comment
Share on other sites

Liquid roll on coatings that are designed for RV roofs, they can be applied over metal. The company has been around for a long time.

Liquid roll on EDPM coating, Seems the easiest way to go but when you apply it the temperature must be above 55 degrees. At this time of year it might take a while to cure if the night time temps drop below 55 and the day time temps are relatively low as well. You can add another coat at a later time. http://www.advancedrubbercoatings.com/site/1584080/page/45031

This is another coating option from the same company. a two part urethane and it too will stick to metal but you only have a one to two hour pot life open time before it kicks off. But at least you can get it to kick off during cooler spring time weather. You will want to be all set up and maybe have a partner to work with so you can get it on quickly. Read the directions carefully to note about the limited window of opportunity for applying a second coat and what it will take to put on a second coat after that time limit has run out. http://www.advancedrubbercoatings.com/site/1584080/page/831707

you will probably need to prime the surface for the best results before using the coatings. Prep work is always important but it looks like you have a great start on it :)

http://www.advancedrubbercoatings.com/site/1584080/page/2477237

Link to comment
Share on other sites

Liquid roll on coatings that are designed for RV roofs, they can be applied over metal.

Yup, that is why I went this route. The sheet EDPM was going to present too many challenges.

I picked up a new tarp today as the one I had been using was from the winter and was starting to seep water through it in places. I'm going to be on a trip next week so wanted a bit of insurance in case it rains heavily. New tarp is in place all strapped down with bungee cords and a couple 2x8's across it so it is not going anywhere.

This is the stuff I went with. I know what you mean about the temps. It has been strait up snowing today. Just a couple of flakes but still too cold to work on the roof.

liquid_roof.jpg

And all the rest of the roof supplies

supplies.jpg

Link to comment
Share on other sites

Nice stash! Getting it is the fun part. Installing it all, not so much :(

I would like a Fantastic Fan with hood for my main vent. But the idea of crawling up on the roof and spending days chiseling off the miles thick roofing compound the previous owner spread around the vent has meant I can think of a hundred other chores to get done first. The vent was not leaking, he was just a gung-ho new owner looking for DIY jobs but he had no skills or patience with such things so he just slopped in on way too thick. Maybe in a couple of years it will hit the top of my improvements to be made list.

Link to comment
Share on other sites

when I saw the amount of caulk/dicor on my roof and the leaks at my seams, I decided I am NOT going to propagate the problem by recaulking the leaks.

Oh, I did not know there was a problem with rubber roof adhering to aluminum skin on the roof,

Link to comment
Share on other sites

Oh, I did not know there was a problem with rubber roof adhering to aluminum skin on the roof,

Not just the aluminum but a lot of the roof coatings that people tend to put up on these roofs are damaging to EPDM. That and it complicates the adhesive part. I starting looking into alternatives but didn't like any of the options. A quick interesting read at an engineering site I've posted questions before as part of my work has this post with some engineers talking about adhering to aluminum. Eng-tips.com I never knew bonding anything was this complicated.

Waiting for it to get just a little bit warmer outside before I head out this morning. So drinking way too much coffee and poking around on the web for more info on all my various projects.

My advice on the caulk and such is a good heat gun and a stiff relatively sharp putty knife. I sharpened one then took a file and rounded the two ends with a slight radius as to not dig into the skin. The baseline caulk/lap seal removal went really fast around the vents and such with the heat gun. Even the removal of the trim wasn't too bad though I've still not taken off the two rear end pieces. There was some silicone up there in spots and nothing I got will dissolve that. I have been using a fine wire brush cup on a 4 1/2" grinder and just going to town with it. Some black roof stuff that had hardened up solid came off fairly easily. The silver roof coating came up easy where it was heavy with heat and putty knife but it seemed the thinner the coat, the harder it was. Here the wire brush made easy work of the silver top and the black underneath came up with basic paint thinner and paper towels. Then I tried Strip Kleen brush cleaner. That stuff worked so much better and faster. Prep, prep and more prep. Working a little here and there, I have about 8-10 hours total labor into it as of today with the couple hours here and there method. Often it takes half the time to uncover then recover with the tarp. I'd love just one weekend with 70 degree temps and nothing but sunshine. I got time though as the first trip is not booked till June 20th.

Alright, enough time killing. I going out and face the cold.

Link to comment
Share on other sites

This stuff works wonders on stripping silicone caulking & will not strip paint off the metal. I have done every seam on my rig and this saved me time in the areas i wanted to clean but not strip.

http://www.mckanica.com/index.php?page=shop.browse&category_id=9&option=com_virtuemart&Itemid=32&vmcchk=1&Itemid=45

Link to comment
Share on other sites

This stuff works wonders on stripping silicone caulking & will not strip paint off the metal.

Thanks Wapiti

Available on Amazon with free shipping. Added to my wish list. Will give it a try as I got plenty more worked planned and see a use for this. How well does it work in vertical applications?

Link to comment
Share on other sites

WD-40 also works on breaking down silicone caulk. Let it sit for a few minutes and rub and scrape.

Link to comment
Share on other sites

Thanks Wapiti

Available on Amazon with free shipping. Added to my wish list. Will give it a try as I got plenty more worked planned and see a use for this. How well does it work in vertical applications?

This works well also. It's a gel, put some in a cup and apply with a 1 1/2" brush. Does not run on a horizontal surface.

http://www.amazon.com/Motsenbockers-Lift-Off-411-Silicone/dp/B002VGINIW/ref=sr_1_4?ie=UTF8&qid=1429981991&sr=8-4&keywords=silicone+remover

My Dolphin has been the recipient of 25 years of half/a**d silicone repairs.

It looks like a, "What not to do to stop leaks" poster.

Of course it still leaks .

I brush this on and let it sit about 30 min.

Link to comment
Share on other sites

The two part product Back East Don bought has a recommended primer that should be used on any areas where there is a doubtful surface prep situation.

To get EDPM to stick properly you have to lightly sand the surface of it, clean it of all dust residue and then apply a specialty primer to the surface of the EDPM.

A good generalized surface prep chart for getting adhesives to bond.

http://www.adhesive.com/instructions_detail_surfaceprep__adhesives_application.html

Using chemicals on aluminum. Not a good idea to use caustic solutions on it. One thing many people don't realize is that aluminum is porous. The porosity can make it difficult to remove all traces of chemicals and caulks from the surface. If you do use a caustic then be sure to use a neutralizer. If you don't know if what you are using is a caustic look at the MSDS sheet for the product, that will tell you. Simple Green is a caustic. Acetone is not and as it leaves no residue behind it is a good last surface wipe preparation cleaner on aluminum before applying adhesives. Appropriate safety measures please, gloves on your hands and remember that is flammable liquid on those rags so don't toss them into the trash can. Do a bucket wash and rinse then hang up for a line dry. Then you can reuse or dispose of them.

Not just the aluminum but a lot of the roof coatings that people tend to put up on these roofs are damaging to EPDM. That and it complicates the adhesive part. I starting looking into alternatives but didn't like any of the options. A quick interesting read at an engineering site I've posted questions before as part of my work has this post with some engineers talking about adhering to aluminum. Eng-tips.com I never knew bonding anything was this complicated.

Link to comment
Share on other sites

The two part product Back East Don bought has a recommended primer that should be used on any areas where there is a doubtful surface prep situation.

Yup, that is the two quarts on the top of the Liquid Roof boxes. For an extra $40 I figured cheap insurance. I watched all sorts of videos, downloaded all the materials and read twice. Spent a few hours out there today doing a bit more prep work. Not the roof but other parts. I sanded some of the trim. It is all going to get repainted. Haven't decide if I'm done for the day or not. Need to grab lunch first.

Link to comment
Share on other sites

What an incredible day out today. Finally some warm weather. Getting there with the roof prep. Today I patched the holes, applied lap sealant at the roof seam and installed the new vents today. A little more prep for tomorrow and Monday is supposed to be in the low 80's. Epoxy primer then two coats of Rubber Roof EPDM.

ready-02.jpg

Link to comment
Share on other sites

A rain shower placed a kink in my 3 day weekend plans to get this done. Primer coat had to wait till first thing this morning. Now I wait and hope the 80 degree weather cures this just a bit faster than 10 hours. That will leave me just enough time to do the Liquid Roof this evening. It is supposed to be warm tonight and in the 70's tomorrow with more possible showers. Once it initially sets, it is supposed to be waterproof, so I should have enough cure time before the rain hits. This is nerve racking. Anyway here is a picture of the primer coat.

primer.jpg

Link to comment
Share on other sites

I can relate. I try to do stuff in FL, clear blue sky and 30 minutes latter it rains, no not rain, pours! Then the sun comes back out, but everything is soaked. Of course now it has rained the humidity is higher than what the instructions call for!

Nice job, thanks for posting. Jim SW FL

Link to comment
Share on other sites

Once the primer coat hit the 10 hour mark I felt it wasn't quite ready to be coated. Read over the labels and pdf. Says it is supposed to be taky. Wait another hour then mix the first gallon. Directions calls for an extended mix period before catalyst and after. Stuff is really thick. I set up two 2x10 across two step ladders as a working platform. I'm pretty tall and can reach more than half way across the roof if I lean in.

Roller and brush are worthless. Tool of choice. 10" cheapo shower squeegee that I got at Home Depot. I bought 3 of these as I figured the foam floor ones would be too big to work around the vents. This worked really well and quickly. Also helped with regulating where I wanted to go heavy.

Got done the first side except the very end and still had quite a bit left in the first can. Moved the make shift staging to the other side and decided to go really heavy with it especially in the trouble spots. Went back over the first side and did both ends down to about 3" above the marker lamps.

Where I had issue with the primer running all over the place the roof coating could be spread thin with the squeegee and it stayed put. Xylene works well at cleaning up oops and drips. Not really great at filling larger pin holes. Went heavy a few times in a couple places. Wish I had flashed them instead of counting on the coating. Lots of lessons learned. It was getting dark but camera managed to get this.

epdm.jpg

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...