Emergency exit on the roof is leaking

etcetera · August 26, 2022

2011 Ford F550 shuttle bus I am trying to convert.

I ran into this issue, my emergency hatch (exit) is leaking pretty bad. I climbed on the roof and this is what I saw. Looks like there is a huge dent, like something fell on it. Maybe a tree? The roof looks warped, both in front of the hatch and to the rear and the hatch is in a pool of water. It shouldn't be like that.

Do you think a tree fell on it? Or this by design? Or the roof warping due to heat?

The hatch was closed and apparently not leaking when I got it, but I opened it and could never close it back correctly.

Edited August 26, 2022 by etcetera

Wrknrvr · August 26, 2022

I would say the first thing to do is to clean the roof so that photos will show exactly what you are dealing with.

Open the hatch again and clean it. The pictures of that subject.

Then we can discuss what the next moves you need to make.

Vern

Kirk W · August 26, 2022

10 hours ago, etcetera said:

Do you think a tree fell on it? Or this by design? Or the roof warping due to heat?

Like Vern said, it is difficult to tell from the pictures but I tend to doubt that it was designed that way and wouldn't think that it would warp due to heat. Since it was not leaking before you opened it I would take a close look at the way it seals and if things are the way now that they were before you opened it. Does the dent cause water to pool up high enough to run in if the hatch were left open?

Ray,IN · August 26, 2022

From all the debris and water stains I'd guess the roof has been that way for many years. It's an emergency exit,and not designed for other use. It may never be water-tight again unless you seal it closed.

etcetera · August 27, 2022

I am going to completely seal that hatch since it has no purpose.

RV_ · August 27, 2022

What is the roof made of? Fiberglass, metal, or EPDM (Rubber Roof) TPO membrane? If it is indeed a damaged section I would hesitate to seal it up and never use silicone for that. If you can tell me that I can give you advice on materials and sealants. Sincee you are removing the old interior can you see it from below? Since RVs vibrate a butyl rubber putty against the skin under the vent/exit frame first and then after it is secured top coat it with RV self leveling caulk. If it a a membrane roof Dicor has patch kits that may work best. But regardless that dent will always fill up with water and cause issues again. You need water to run off not pool.

https://dicorproducts.com/

Ray,IN · August 28, 2022

Depending on the type of structure, the roof might be lifted up to level or slightly above in that section if you are already going to remove the present ceiling.

etcetera · August 28, 2022

fiberglass, the shuttle bus is fiberglass.

I only want to seal the hatch and eventually replace the entire section.

RV_ · August 28, 2022

Glassing in a section might be your best bet then. Can you do fiberglass work and shoot gel coat or will you need to bring it to a boat/RV/body guy?

Kirk W · August 28, 2022

Who built the bus body? You might be able to get some information on the structural makeup from them. I would think that it has some type of metal framework with a fiberglass skin.

RV_ · August 28, 2022

If you want to just temporarily seal it with minimal cost and fuss then when dry remove the hatch. It looks like it has black self leveling caulk on top and a flange like regular RV vents that is screwed to the frame work through the roof. If there is a plastic trim piece lining the inside of the vent opening inside the bus, remove that and you will see if it is a wood frame around the vent or metal. They show that inside trim piece in the video.

Make sure you put an arrow on the outside of the vent with a sharpie indicating front so it fits back correctly.

You will need a roll of butyl rubber caulk tape, and at least one tube of self leveling caulk. If you have a Mobile home supply place near you they usually carry that cheaper than any RV or boat place. I like to use plastic scrapers to remove the old caulk and putty so as not to gouge the roof. Repair the old holes with a dowel cut to size for each.

From the top you will need to remove the caulk and sealant and clean it or remove the screws.

Watch this video and heed the no silicone warning and if you remove the sealant and cleaned it then use butyl rubber tape and then screwed it down trimmed the excess butyl tape squeezed out when you screwed down the vent flange with your plastic putty knife. and applied your self leveling caulk and made sure it was not rained on or puddled for a day it should hold even underwater as long as you started the self leveling caulk higher than the water level now, it should hold for a while until you can replace that section. If you use those wonder tapes getting it off the fiberglass will be next to impossible. They are OK for temporary repairs on membrane roofs because the membrane can be cut out and patched with Dicor repair kits.

Watch this video all the way through and that should be you least costly and most likely to hold repair.

I do not like the power multi tool as an option as I have never had an issue using a plastic putty knife on the roof around it to remove caulk and butyl tape. I do use a metal pick to clean the screws so the bit can get a grip.