Water on rubber Roof

[jk1]

We have a spot on our roof on our brand new 2024 coleman lantern trailer where water tends to pool. This has caused a brown spot on the rubber membrane. Is this normal? Will this cause the rubber to wear out and leak through to the roof underneath the rubber membrane? We have taken it to the dealer and they say this is normal for it to discolor, and will not repair it under warranty because the manufacturer, Keystone, claims there is nothing wrong. We are worried that the brown spot is an indication of water damage and will cause the rubber membrane to fail soon and cause damage underneath the membrane.

[JBarca]

Hi JK1,

I may be able to help. I have restored many water-roof-damaged campers and can pass along some of what I have  seen and found when doing roof repairs.

A few things, you called your roof to be a rubber roof.  Sadly, the RV industry stopped using actual EPDM rubber a number of years ago.   TPO and PVC membranes are now very common for travel trailers. Both  are a plastic formulation, no rubber at all.  This link to the Coleman site states the Lantern model uses a TPO membrane on a 3/8" decked full walk on arched roof. https://www.dutchmen.com/product/coleman-lantern#constructionOption   If you have something other then the what I found, please tell us what it is you have.  

The pooling or ponding as many roofers call it, can be a long term problem depending where the ponding is occurring and if it constantly ponds in the same spot.    Repetitive ponding happens when the decking has sagged and there is a low spot when the camper is setup level or even nose up or down sometimes.  Left over dirt and mold as time goes on will create a discoloration in the ponding area.  The water evaporates and what is left is the mold/dirt etc. concentrated in that area. The actual membrane can withstand the ponding in it's virgin form, however any caulking/roof sealants that are under water during ponding can be a problem over time.

Can you post a few pics of the roof showing the discoloration and where it is located in relation to any roof seams?  It is easier to talk to what you are seeing then just generic answers. 

I hope this helps.

John

[way2roll]

Water pooling on an RV roof would concern me simply for the risk of it finding it's way into one of the many penetrations. RV roofs should have a pitch/dome to keep this from happening. I would push the manufacturer harder. My only question to the OP is, is your RV level?

[jk1]

The dealer told us to keep it on an angle with either the front up higher or down lower to try to keep it from pooling, but at this point the original damage is done, and it hasn't rained again since then, so we will see when it rains again if that helps.

[JDsdogs]

This is caused by a low spot in the roof or membrane. Water is pooling there, when it dries/ evaporates it leaves the brown spot behind. The minerals left behind can’t be good for the membrane and may well shorten its life. Definitely be bad if pooled water is allowed to freeze. 
It’s a shame that Keystone is not taking care of this issue.