Today water started leaking out from between the membrane on the very bottom of the 5er and the metal frame the screws that hold it on are attached to. Upon inspection, the membrane was full of water all the way across the trailer and the entire area in from of the first axle was sagging severely. We shut off the water spigot, cleaned everything out of the basement, there was no water in the basement, and removed the wall to gain access to the area behind the water valves. With the wall removed we inspected everything and saw no leaks. So we turned the spigot back on there were no leaks anywhere. Next, we turned on the water in the kitchen sink, bathroom and shower one at a time. There were no leaks. After that we removed all the screws that were holding the membrane on one side. Here, we could see where water had been, but couldn't tell where it was leaking. I think our next step is to remove all the screws from the membrane in front of the first axle and pull the membrane down to get a better view. But before I do all of that, I thought I'd ask all the knowledgeable people who might have been here before. Is there a better idea than removing the membrane? Can you offer me any ideas of how that area could get wet? The wet area is all below the basement floor. By the way our trailer is a Grand Design Solitude 369RL.

Really, the only way to know for sure is to drop enough of the coroplast down so you can get eyes on everything. Before you do that, you might want to carefully drill a hole at the lowest point of the coroplast to let the water out gently instead of all at once when you are on your back on the ground under the tank. Watch out for pipe and wires. Hopefully (if it's not a water line leak) it's not your black tank.Had that happen last year. Found the leak by filling the grey tank. Turned out to be a flange along the top of the tank that (of course) only leaked when it was full. I had to put in a new tank and put in a couple of extra support straps under it to take some of the weight off the flange when it was full. I also strapped the black tank as well since I was looking at it. Hope this helps.

There is a recall on some models. Apparently water laying in the coroplast "membrane" can cause electrical issues because of the way trailers are manufactured. These trailers and probably most other brands have all the electrical and plumbing just laying loose and supported by the coroplast "membrane" thus nothing is tied to the frame or structure!!! If that fills with water you can have major electrical issues and possibly even danger because all that stuff could be laying in water. Water can actually be forced in or find it's way in between the screws holding up the coroplast!! Imagine the pressure especially in the front when traveling in heavy rain at 60 MPH. Water will come in and lay in the lowest point causing it to sag even more with the weight of water!! Check with Grand Design to find if your unit has the recall. They may take care of this for you. I agree with one post that suggested you drill holes in the lowest point of the coroplast to let water out before removing any screws yourself!! It could be very heavy and fall when the last screw is removed.

Check out HappilyeverHanks on YouTube. There is too much to just be a coincidence. Same 5th as you, not sure the year. They posted their problem not to long ago-

Have you inspected the water pump area?

Water leak, we cannot find. | Good Sam Community

pianotuna
Nomad III
Mar 19, 2022
From the roof?
ssthrd
Explorer
Mar 19, 2022
Really, the only way to know for sure is to drop enough of the coroplast down so you can get eyes on everything. Before you do that, you might want to carefully drill a hole at the lowest point of the coroplast to let the water out gently instead of all at once when you are on your back on the ground under the tank. Watch out for pipe and wires. Hopefully (if it's not a water line leak) it's not your black tank.

Had that happen last year. Found the leak by filling the grey tank. Turned out to be a flange along the top of the tank that (of course) only leaked when it was full. I had to put in a new tank and put in a couple of extra support straps under it to take some of the weight off the flange when it was full. I also strapped the black tank as well since I was looking at it.

Hope this helps.
Likes_to_tow
Nomad
Mar 19, 2022
There is a recall on some models. Apparently water laying in the coroplast "membrane" can cause electrical issues because of the way trailers are manufactured. These trailers and probably most other brands have all the electrical and plumbing just laying loose and supported by the coroplast "membrane" thus nothing is tied to the frame or structure!!! If that fills with water you can have major electrical issues and possibly even danger because all that stuff could be laying in water. Water can actually be forced in or find it's way in between the screws holding up the coroplast!! Imagine the pressure especially in the front when traveling in heavy rain at 60 MPH. Water will come in and lay in the lowest point causing it to sag even more with the weight of water!! Check with Grand Design to find if your unit has the recall. They may take care of this for you.

I agree with one post that suggested you drill holes in the lowest point of the coroplast to let water out before removing any screws yourself!! It could be very heavy and fall when the last screw is removed.
mike_kellie
Explorer II
Mar 20, 2022
Check out HappilyeverHanks on YouTube. There is too much to just be a coincidence. Same 5th as you, not sure the year. They posted their problem not to long ago-
time2roll
Nomad
Mar 20, 2022
Have you inspected the water pump area?
bgiroux
Explorer
Mar 20, 2022
My guess is that you have a cracked drain in your shower that only leaks when under strain from the floor flexing while you are standing in the shower with the water running. Try having someone walking around in the shower while the water is on and see if you see leaking below. We’ve had 2 trailers with that exact problem.
noonenosthis1
Explorer
Mar 20, 2022
That happened to us with our first brand new trailer. It had rained and water had leaked by the refrigerator vent on the roof through the wall and then into that membrane. This was back in 2007 and I remember seeing that saggy bottom. ugh
MFL
Nomad II
Mar 20, 2022
Likes to tow wrote:
Imagine the pressure especially in the front when traveling in heavy rain at 60 MPH. Water will come in and lay in the lowest point causing it to sag even more with the weight of water!! Check with Grand Design to find if your unit has the recall. They may take care of this for you.

OP...have you recently been traveling in the rain? Likely source of water intrusion.

Jerry
jdc1
Explorer II
Mar 20, 2022
Just went through something similar. I found the PEX piping had been chewed through just enough for a pin hole leak. Yea, it's a pain to remove the Coroplast belly cover, but, you'll need to replace the wet insulation anyway. I added more insulation before I screwed it all back on. Just do one side at a time until you find the leak. It makes putting the Coroplast belly back one easier (lining up screw holes).
klr650goldwing
Explorer
Mar 20, 2022
We have been parked in the same site since January 5th of this year. We are winter Texans along the gulf coast. So the trailer hasn't moved and it really hasn't rained enough to talk about all winter. The shower is located above the trailer basement so if that is the location of the leak I'd think the basement would be wet, but there is no water in the basement. This leak seems to be below the basement, granted there really isn't anything below the basement other than that plastic membrane. So all I really know is that the leak is very low in the trailer. We will be heading for home in about two weeks so we have decided to cut a hole in the membrane at the lowest point and just head for home. If it leaks along the way all the water will be able to escape out the hole. Once we get home we'll take the trailer to the dealer where we bought it and let them find the leak and fix it. When I first noticed the badly sagging plastic membrane hanging down so low and obviously filled with many gallons of water I panicked a bit, but with the help of ya'll and thinking it all through I've calmed down and we'll be fine going home. Thanks for your help.