Soft floor in front of RV’s kitchen sink. How do we fix it?

Dear Dave, 
Our RV’s sink had a cracked pipe and when we turned the water on it went everywhere. We shut it off immediately. But we then worked on the sink and the water had gotten on the floor. We noticed two days later it’s soft in front of the sink. How can we fix this? —Lindsay, 2015 Forest River Flagstaff

Dear Lindsay,
I would believe that you had a water leak quite a while before you noticed it, as the floor typically would not get soft that fast. If you have fixed the leak in the sink, verify that nothing else is leaking such as below windows or at the sidewall to floor joint.

The Flagstaff models have several different floorplans with some having an island in the kitchen with the sink. Most floors are a sandwich design of a thin underlayment of luan plywood, block foam insulation, and a layer of plywood, and either carpet or vinyl flooring material. Typically, they have a perimeter frame of either wood or metal and cross members of wood sandwiched in the floor. However, seldom are they uniform like residential construction that is 16” on center for wall framing and 24” for floor joists; rather, they’re random and difficult to identify.

Where to start

I would start by peeling back the flooring, which I assume would be vinyl, in the kitchen area. You should be able to cut a straight line in the fake grout line in a square and peel it back to see what extent the damage is to the wood substructure. It may be as easy as letting it dry if the wood hasn’t started to separate or disintegrate.

It may also be just a heavy traffic area and the wood is not wet but has become weak due to insufficient support and the block foam breaking down. Pulling back the flooring will help identify what is happening. You may also be able to look underneath in a compartment to see if there is a way to reinforce the flooring with additional cross members from the underside.

If the floor is deteriorated or spongy, you will need to cut out the bad wood area and look at the insulation as well. Here is a screen capture of the bad floor in a travel trailer we worked on. The water damage had even ruined the wooden joists in the flooring, which had to be replaced as well. Hopefully yours is not this bad.

Start with small area of floor

If you do need to cut away some of the floor and replace it, start with a small area and try to find the joist or cross member. When you find it, cut along the edge of the joist, then you can attach a 2×4 to the existing joist that will help support the new wood. You may even want to add a cross member of 2×4 from one joist to another to help support the new flooring in a heavy traffic area.

You should then be able to use adhesive to lay the vinyl flooring back down and run a light bead of clear silicone over the seam. There are also some good adhesives available in the flooring section of home improvement stores.

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Can my RV have soft floors even without a water leak?

Dear Dave,
Can soft spots develop on the floor of my 5th wheel trailer without being caused by water damage? We have a 2017 Primetime Crusader Lite, model 30BH. The soft spots started 2 years after we bought it new, mainly at high traffic areas. No signs of water anywhere in the rig. Had the rig checked for exterior and plumbing leaks but none found. When I removed a floor register, I noticed the actual laminated wooden part of the floor was maybe 5/16″ thick, definitely less than 3/8″. Couldn’t see how far apart the joists were. There’s about 1 1/2″ to 2″ of high density foam underneath the flooring. Anyway, is it possible to have delamination and/or soft spots without any water damage? Thank you very much! —Tom L.

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Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”

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