Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > TRAVEL TRAILER, 5th WHEEL & TRUCK CAMPER FORUMS > 5th Wheel Discussion
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 04-09-2021, 01:38 PM   #1
Junior Member
 
Join Date: Apr 2021
Posts: 5
Repairing damaged floor from gray tank leak

Hi all! I'm new here, and I'm looking for a little insight into what's looking like a fun repair.

I bought a 2010 Keystone Montana in August, and shortly after buying a noticed a soft spot in the kitchen floor. Not mushy, but definitely soft. The previous owner had replaced the original flooring with vinyl plank, so while I couldn't see any signs of water damage, I had to take her word that there was no damage when she put in the new flooring.

Unfortunately, last week I found out that there's a leak in the top of the gray tank - which sits RIGHT below the soft spot in the kitchen. So I think we found the problem. I can see where the sink pipe goes into the gray tank, and the flooring looks to be a sandwiched plywood-foam-plywood (or similar). The gray tank sits right up against the flooring.

I've seen in other threads that the most common way to fix flooring like this is to go in from the top, but since the problem is beneath, and I already have to pull the gray tank down to fix it, I'm thinking that I'll have to go in from the bottom and replace all three layers. My plan is to disconnect and drop the gray tank (then repair/replace as needed), then cut into the floor from beneath, and replace what's damaged.

Does that sound reasonable? Does anyone know what kind of foam insulation (it looks like it's 2.5-3" thick) to use? Would you go in from the top instead? Any advice is greatly appreciated!
hannanm is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 04-09-2021, 02:02 PM   #2
Senior Member
 
Boogie_'s Avatar
 
Join Date: May 2013
Location: SW Louisiana
Posts: 617
I have replaced a few floors, don't know how you could do it from underneath.

The new decking will need to span across at least 2 floor joists.

Unless I'm misunderstanding your question.
__________________
A bunch of salvage title junk I rebuilt
Boogie_ is offline   Reply With Quote
Old 04-09-2021, 04:39 PM   #3
Community Moderator


 
Join Date: Aug 2018
Location: Full timing
Posts: 4,045
I have repaired 2 soft spots, had to go in from the top both times. How will you judge the distance to cut out the bad wood, without cutting thru the top floor. The top floor needs to come out.
__________________
2018 Road Warrior 427/2016 golf cart (gas) sold
2013 Can Am Spyder RT Limited
2017 Ram 3500 w/Aisin w/4:10
2 Dachshunds DJ (RIP 9-12-19) & Joey (RIP 5-14-21)
hamm2018 is offline   Reply With Quote
Old 04-09-2021, 05:46 PM   #4
Junior Member
 
Join Date: Apr 2021
Posts: 5
Thanks to both of you! I took out the flooring to find the plywood in great shape - just a soft spot from poor structural support around the heating vent. So...a lot of work for nothing, but I'm sure glad I don't have to replace the entire section of subfloor! I guess it was just a coincidence that the soft spot lined up with the leaky tank. Now on to fix the gray tank (and make sure that it didn't do any other damage with its leak)...
hannanm is offline   Reply With Quote
Old 04-09-2021, 07:08 PM   #5
Senior Member
 
Winnebago Owners Club
Join Date: Sep 2015
Posts: 1,779
Quote:
Originally Posted by hannanm View Post
Thanks to both of you! I took out the flooring to find the plywood in great shape - just a soft spot from poor structural support around the heating vent. So...a lot of work for nothing, but I'm sure glad I don't have to replace the entire section of subfloor! I guess it was just a coincidence that the soft spot lined up with the leaky tank. Now on to fix the gray tank (and make sure that it didn't do any other damage with its leak)...
I would not see how a leaky gray tank would cause damage to the floor from the underside. Does it leak when it's only 1/4 full or do you have to get it nearly full? I had a minor leak on my last coach but it only showed up when it was over 3/4 full. Never could find it. That vintage of Keystone is kind of known for having soft floors. One of my winter neighbors has a 2009 bought brand new and it was soft almost from the first day. Never seemed to get any worse so if yours doesn't, other than being a bit annoying I wouldn't worry about it. The bigger issue is the insulation. We had a flood in the park last year and all the 5rs and bumper pulls got wet insulation. The repair guy just stripped it out and used some kind of 3/4 in garage floor insulation to replace it. Search around a little. I'm a M/H guy but somebody will know the fastest easiest way to do it.
amosnandy is offline   Reply With Quote
Old 04-10-2021, 12:28 AM   #6
Community Moderator


 
Join Date: Aug 2018
Location: Full timing
Posts: 4,045
Quote:
Originally Posted by hannanm View Post
Thanks to both of you! I took out the flooring to find the plywood in great shape - just a soft spot from poor structural support around the heating vent. So...a lot of work for nothing, but I'm sure glad I don't have to replace the entire section of subfloor! I guess it was just a coincidence that the soft spot lined up with the leaky tank. Now on to fix the gray tank (and make sure that it didn't do any other damage with its leak)...
Glad it was NOT the flooring. Get an inspection camera and see if you find where the leak is coming from before you tear into anything. it may save you some work. I picked one up for around $50 and have used it and it has saved me some work.
__________________
2018 Road Warrior 427/2016 golf cart (gas) sold
2013 Can Am Spyder RT Limited
2017 Ram 3500 w/Aisin w/4:10
2 Dachshunds DJ (RIP 9-12-19) & Joey (RIP 5-14-21)
hamm2018 is offline   Reply With Quote
Old 04-10-2021, 06:36 AM   #7
Senior Member
 
Boogie_'s Avatar
 
Join Date: May 2013
Location: SW Louisiana
Posts: 617
Quote:
Originally Posted by hannanm View Post
Thanks to both of you! I took out the flooring to find the plywood in great shape - just a soft spot from poor structural support around the heating vent. So...a lot of work for nothing, but I'm sure glad I don't have to replace the entire section of subfloor! I guess it was just a coincidence that the soft spot lined up with the leaky tank. Now on to fix the gray tank (and make sure that it didn't do any other damage with its leak)...
Good deal.

My last 5ver had a soft spot like that too.
Very bad design with the ducting, they cut right thru one of the floor joist in a high traffic area.
Not a problem for my wife and daughter but I'm a big guy, 6'4"/250lbs, and had to be very mindful of were I was stepping.

The term I used for things like this is: afterthought-engineering.
__________________
A bunch of salvage title junk I rebuilt
Boogie_ is offline   Reply With Quote
Old 04-10-2021, 10:36 PM   #8
Junior Member
 
Join Date: Apr 2021
Posts: 5
Quote:
Originally Posted by amosnandy View Post
I would not see how a leaky gray tank would cause damage to the floor from the underside. Does it leak when it's only 1/4 full or do you have to get it nearly full? I had a minor leak on my last coach but it only showed up when it was over 3/4 full. Never could find it. That vintage of Keystone is kind of known for having soft floors. One of my winter neighbors has a 2009 bought brand new and it was soft almost from the first day. Never seemed to get any worse so if yours doesn't, other than being a bit annoying I wouldn't worry about it. The bigger issue is the insulation. We had a flood in the park last year and all the 5rs and bumper pulls got wet insulation. The repair guy just stripped it out and used some kind of 3/4 in garage floor insulation to replace it. Search around a little. I'm a M/H guy but somebody will know the fastest easiest way to do it.
It actually only leaks when it's full to the top, so a leak in the top or where the pipe connects. Obviously I know it shouldn't be getting that full, but the sensors don't work so it's happened 2 or 3 times. Unfortunately the tank sits right up against the subfloor, so you can't see anything except the water coming out of the side. I can't feel directly above the tank since it's right against the subfloor, but all of the plywood around it is in great shape, so I think the waterproof fabric around it did it's job. And you're right - there was no connection between the soft spot and the tank leak. Just a coincidence! Thanks for your help!
hannanm is offline   Reply With Quote
Old 04-10-2021, 10:38 PM   #9
Junior Member
 
Join Date: Apr 2021
Posts: 5
Quote:
Originally Posted by hamm2018 View Post
Glad it was NOT the flooring. Get an inspection camera and see if you find where the leak is coming from before you tear into anything. it may save you some work. I picked one up for around $50 and have used it and it has saved me some work.
Great idea! I already had the insulation down so I thought about pulling down the tank, but it's an insane job. I just did a patch on a black tank but this looked way harder, just based on where it's located. I'm stationary for now, so I'm just going to leave the gray tank open and not risk filling it to the point of that leak. Thanks for your help!
hannanm is offline   Reply With Quote
Old 04-10-2021, 10:42 PM   #10
Junior Member
 
Join Date: Apr 2021
Posts: 5
Quote:
Originally Posted by Boogie_ View Post
Good deal.

My last 5ver had a soft spot like that too.
Very bad design with the ducting, they cut right thru one of the floor joist in a high traffic area.
Not a problem for my wife and daughter but I'm a big guy, 6'4"/250lbs, and had to be very mindful of were I was stepping.

The term I used for things like this is: afterthought-engineering.
That's exactly it with the ducting! I took apart the vinyl plank flooring because I couldn't stand not knowing - I'm so glad there was no water damage, but now it seemed silly to do all that for nothing! Since I was in there, I drilled a few small holes where the soft spot was and filled it with spray foam insulation - the soft spot was caused by the plywood sitting about 1/8" above the styrofoam, so that filled it up. Who knows if it'll hold, but couldn't hurt. Thanks for your help!
hannanm is offline   Reply With Quote
Reply

Tags
air, floor, gray tank, leak, repair, tank



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
New Aire Gray tank leak and Sanicon hose leak cinergi Newmar Owner's Forum 29 08-23-2018 11:51 AM
repairing ripped vinyl floor jbrinsmead Travel Trailer Discussion 4 07-26-2015 01:48 PM
Repairing sub-sub floor FlyingChops Alpine Coach Owner's Forum 7 07-21-2014 10:36 PM
Repairing water-damaged inside sidewall p00ches Winnebago Industries Owner's Forum 1 08-28-2013 09:35 PM

» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 12:21 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2023, vBulletin Solutions, Inc.