Shower Skylight install Idea - Opinions wanted - Henry 887HS

[searcherrr]

I have a big issue right now with roof leaks on our 27ft E450 Class C.

Knowns:

• Apparently most of the previous roof patches have reached their life and are giving way to water.
• Apparently when there is a bad spot on the roof the thin under sheath of wood (not sure what its called) becomes wavy or bubbly under the EPDM rubber sheet
• Previous owner had a roof accident that looked to have affected "ALL" items on the roof: Skylights, a/c, luggage rail mounts in rear, antenna etc..
• I would say the roof was patched EVERYWHERE (20 or so spots) EVERYTHING goes down into the roof.
• We've already had to remount the a/c to flush the gasket right so it wouldn't leak "UNDER THE EPDM" which is what it was doing a while back
• Recently found 2 new leaks at shower skylight and rear luggage rack mount or where ladder goes into the roof

Ok, have done a lot lot lot lot of homework on all this before starting the project. Camper roof is tarped with a giant tarp till I can get it prepped and fixed up right.

I have decided on this product because it gets many 5 star reviews and claims LIFETIME 1 time FIX IT and you are DONE for GOOD, no biannual inspections of the roof for leaks etc.. no more roof work, just lay a new roof layer on and you are finished:

Henry Tropi Cool 887 HS - Formulated especially for RV EPDM roofs: http://www.homedepot.com/p/Henry-Tropi-Cool-4-75-Gal-887-White-100-Silicone-Roof-Coating-HE887HS073/205049553

***** SHOWER SKYLIGHT IDEA - SCREWLESS INSTALLATION *****
HERE'S WHERE I'D LIKE OPINIONS. To me, it is pretty counterintuitive to send SEVERAL (like 20 or more maybe) screws into and through the roof to mount the shower skylight.
I saw some ideas here:
http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/23453365.cfm
and here:
http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/21771654.cfm

What I'm thinking is since i'm going to prep, clean etc.. scrape of ALL old sealant patches EVERYWHERE there is a current LEAK and have decided to use the Henry 887 HS product, why not just use proper sealant and BUTYL tape to "mash seal down" the new Skylight flanged edges, and THEN USE NO SCREWS AT ALL....... THEN.... COME BACK BEHIND ALL THAT SEALED STUFF AND LAY THE ENTIRELY NEW ROOF LAYER OF HENRY 887 HS TROPI-COOL ROOF ACROSS THE ENTIRE camper roof, including the new shower skylight flange edges, such that the 887 HS new layer is covered over the BUTYL tape/sealant thereby sandwiching the shower skylight into place??????

I can't see why that wouldn't just stay PUT? Does anything thing the winds of going down the interstate would actually try to pull the shower skylight dome OFF after its sealed down so well under all that I've said???

I know that dicor and other things have been on the roof for YEARS and never moved much at all, if even 1mm, so I was thinking to avoid a whole bunch new screw holes... maybe this would work.

What ya'll think and what (if anyone knows or has opinion) do ya'll think of the Henry 887 HS product?

**Disclaimer: FYI - I know full well to avoid silicon products on RV's, big NO NO.. but the 887 HS product is different and specially formulated for EPDM roofs and even comes with special RV instructions.**

It is either this or we have to get rid of the camper, because I'm not coating the roof every year or every 6 months. Supposed to be enjoyable... not constant maintenance!!! lol (i know thats impossible, but at least on the roof part I'd like to set it and forget it).

[W4RLR]

I think that the skylight manufacturers put screw holes in the skylight flange for a reason. I would be hesitant to just rely on adhesive alone to hold the skylight in place. A lot of heat on the roof could cause the adhesive to soften and lose strength. When I replaced the skylight in my fiver, I used screws that had an integral washer on the head to lessen the stress on the plastic, setting the skylight on a bed of butyl tape. No leaks so far, and we've had a few big thunderstorms since the skylight was installed.

[Dr_Quick]

If the wood below the EPDM membrane is wavy or bubbly, the wood deck is probably rotting and needs to be replaced. Just working on the existing membrane to stop leaks will not stop deterioration of deck below. I would recommend an inspection of the wood deck before any repairs are attempted. I have repacked an entire roof membrane and deck due to rotting wood on one trailer, and another had to rebuild front corner due to rotting wood deck.

[westend]

The Henry roof coating won't afford water sealing to any through holes in the roof . The product information states that it is resistant to pooled water. That is not the same.

For a skylight, I'd use an adhesive specified by the Mfg of the skylight, some screws and washers to retain it (allowing for thermal expansion/contraction) and then seal any through hole in the roof membrane with Eternabond tape. AFAIK, Eternabond tape is the only sealing material that has a long life. After everything is sealed correctly, you could then coat the entire roof with a top-coat paint. I wouldn't use a silicone based product. I used an elastomeric top-coat that has held up well.

[Homer1]

I do not have any opinion on most of the things you are going to do. However I can tell you I replaced 7 skylight over the shower plastic bubbles in the first two years I owned my new Itasca. The plastic dome would crack down in Florida. The factory instructed the dealer not to use screws in the lower flange of the bubble. Apparently it has to be able to move, expand and contract with the heat of the day/night

[path1]

I didn't read you whole post, but on skylights...When I did my skylights, I had to call the manufacture about something. In talking with their tech dept and they said only to use "SB 140". As other sealants "might" react to the type of plastic used in skylights. The SB 140 works good as a sealant but a real pain to work with. Also I used 3/4 inch fender washers to dissipate stress.

Also be careful about any wires are located near the skylight, if you're making new screw holes. Don't get wires mixed up in screws.

If roof is that KO'd, why not just replace and be done with it?