The floor underneath my fresh water tank was rotten. Just demo'd it. Pulled out the water tank. Plan is to clean up the metal support structure, put in a new floor and install the water tank back. The replacement floor will be about 4x8' with a cut out for the dump valves. Couple of concerns..1) What do I use for the flooring? Need protection from road hazards on bottom and it needs to be strong enough to support a 6' x 4' vinyl water tank (there are 2 metal cross braces). Thinking about a sheet of marine plywood. 2) There was no drain anywhere on the old floor. Should there be one and if so, what kind?Any comments welcome.Thanks!

I would try and find the source of the previous leak to mitigate the risk of it happening again.

I would use treated (yellawood, wolmanized) plywood, probably 5/8" thick.

Why not go with a sheet of aluminum and eliminate the problem forever? For about $300 you can buy a 4 x 8 sheet of 3/16" thick aluminum which, with the metal braces, would be more than strong enough to support the water tank.

Our Phaeton floor rotted due to a cracked basin nut on the shower drain above the tanks. Tiffin has came up with a 1" composite plastic sheet to replace the vinyl clad treated plywood panel used before, this has been the standard for construction for several years now.

I'm a little surprised your Tuscany does not have an insulated subfloor the tanks set on, but use at least 5/8" marine ply, with a 16 gauge galvanized sheet metal cover on the bottom for protection. You can either use contact cement, or construction adhesive to attach it to the ply. If you do not have a fresh water tank drain now, I certainly install one at this time. Don't worry about the size of the tanks, but how much water they will hold. Use 8 pounds per gallon for weight that the floor must carry.

Basement floor replacement under fresh water tank

AikenRacer
Explorer
Jan 14, 2017
The subfloor did have the metal layer on the bottom and some sort of fiberglass looking stuff on the top but the wood just delaminated badly. All of it is out now. I like the idea of the poly vinyl sheet as the base. Never worked with it. Does anyone have any experience working with this stuff?
wildmanbaker
Explorer
Jan 14, 2017
I'm a little surprised your Tuscany does not have an insulated subfloor the tanks set on, but use at least 5/8" marine ply, with a 16 gauge galvanized sheet metal cover on the bottom for protection. You can either use contact cement, or construction adhesive to attach it to the ply. If you do not have a fresh water tank drain now, I certainly install one at this time. Don't worry about the size of the tanks, but how much water they will hold. Use 8 pounds per gallon for weight that the floor must carry.
Teacher_s_Pet
Explorer
Jan 14, 2017
Our Phaeton floor rotted due to a cracked basin nut on the shower drain above the tanks. Tiffin has came up with a 1" composite plastic sheet to replace the vinyl clad treated plywood panel used before, this has been the standard for construction for several years now.
rgatijnet1
Explorer III
Jan 14, 2017
Why not go with a sheet of aluminum and eliminate the problem forever? For about $300 you can buy a 4 x 8 sheet of 3/16" thick aluminum which, with the metal braces, would be more than strong enough to support the water tank.
fuzzyface
Explorer
Jan 14, 2017
I would use treated (yellawood, wolmanized) plywood, probably 5/8" thick.
Effy
Explorer II
Jan 14, 2017
I would try and find the source of the previous leak to mitigate the risk of it happening again.

Forum Discussion

Basement floor replacement under fresh water tank

About Motorhome Group

Related Content

Moving forward with flooring replacement

Water Heater Replacement Recommendations

Floor Replacement

Basement Door Latch replacement

Flooring Replacement