Bitumen paint on timber

[Craig]

I have been getting the recently purchased camper ready to take out bush and had to do a repair on the ply floor. It looks like the previous owner drove off with the stabiliser legs down and cracked the floor. The underside of the floor has not been painted. It looks in good condition so I suspect it is marine ply. What are your thoughts on painting with a bitumen paint or simply an oil based paint?

Craig

[jon_d]

The Bedford is 46 years old.

The ply floor is still intact and the underneath is coated in Bitumen and paper.
The steel is also coated in gal and then bitumen.

The only rust (which is/was very minimal) is where the bitumen has been sand blasted off.

[Craig]

Thanks Jon.
Has the bitumen leached through the ply at all?

[jon_d]

No, it was > 1/2 inch ply.

Once it sets, it's pretty hard. Also to apply, heat up the sealed can in the sun or in the car boot.

Nice and soft. Makes it easy to pour into cavities to seal them too.

[BruceS]

Once you get it on I hope you never have a leak inside. It'll never dry out before rot sets in!
Don't ask me how I know!!
Take REAL good care to seal the edges as that's usually where the outside moisture will enter.

[Craig]

Thanks Jon.

Hi Bruce,
Only a small chance of a leak inside. It is the teardrop camper so only one door, one window and one skylight hatch. The previous guy screwed through the floor so now some screws are protruding the underside of the floor (exposed to the road). The plan was to cut them flush and paint the bitumen on to seal. But as the ply looks like new and it is 5 years old I was wondering whether it needed it at all or apply bitumen or simply an oil based paint to seal. I have used bitumen on steel but never on timber and was after any info on any downside to doing this.

Craig

[T1 Terry]

Have you thought about the stuff they paint pools and bathroom areas with? I think it's some sort of plastic based paint and it soaks into anywhere it can get and then sets locking out moisture while bonding to anywhere it can get a hold so it doesn't come off easily.
The other option is a mix of Tectyl, fish oil and diesel, that will leach into every available spot and the Tectyl will dry with a wax finish sealing out anything.
The big bus had a heavy coating of bitumen sealing every where, every panel joint, under the floor, even around the window frames. The water got under the bitumen and eat everything available because the bitumen protected it from evaporating and every where the 7 core plywood flor crossed a beam or came into contact with the metal it rotten out for the same reason. The floor inside had a heavy vinyl floor well glued and sealed really well. The floor under the vinyl was perfect, it was all rotten from the underside up not the top down. Where the windows leaked the bus had about a foot of water by the time it reached the back wall because of the slope it was parked on, it was only the fact the level reached the front door that it wasn't deeper, but it got a real good wash when the guy at the bus yard drove it down the hill to get out the driveway

T1 Terry

[pet-els]

T1, are you saying that it actually drove once ??

PeterH

[homeless]

Just a warning about painting over bitumen as when I did my trade the tar would bleed through any paint and we used to apply silver frost first. (I know showing my age).

[jon_d]

"silver frost first. (I know showing my age)"

which is now in the whiskers.