Weatherproofing underside??

[rogersmomma3]

I'm new here, just getting ready to start building, and have a question about weatherproofing. I am planning on building a kitchen and storage unit on top of a 4x6 trailer we own. It will just be an enclosed box with a back hatch that opens up to a teardrop style kitchen. The front part will just be storage to carry all our camping gear. This trailer is topped with 3/4" pressure treated plywood and has been exposed to the elements. It is in good shape with no rotting or damage. But it isn't one solid piece (it's two pieces butted together) and has some holes drilled through it where a toolbox and motorcycle rack where mounted. Can I just leave this wood down, cover the holes and cracks, and weatherproof it? Or should I replace it with a new solid piece? If I replace it with pressure treated plywood do I still need to weatherproof it? I'm trying to do this project as cheap as possible.

[bobhenry]

Filon sheet or maybe just some paint glue and material placed over the taped shut holes. Ice dam tape is a great thing to use to seal joints and perforations that will be covered.

Here is my little chuckwagon design plan.................

and the real thing........http://www.tnttt.com/viewtopic.php?f=48&t=30307&start=105

[rogersmomma3]

That's exactly what I'm looking at building! How awesome to see the end result. I was looking at an old article in Mother Earth News with this set-up & your diagram looks like you started with the same building plan and modified it - am I right? I love it.

[rogersmomma3]

So, are you saying that I don't need to cover the bottom with the asphalt sealing stuff? Just a solid coat of paint after I cover all holes/cracks? That'd be awesome. I don't know what ice dam tape is and my internet searching so far has not lead me to anything that looks right - could you enlighten me??

[KCStudly]

Search "ice membrane roofing".

Its a sticky backed rubber sheet good often used under roofing to form a barrier layer for ice damming. Supposedly it "self heals" if you drive a nail through it.

[dales133]

Search "ice membrane roofing".

Its a sticky backed rubber sheet good often used under roofing to form a barrier layer for ice damming. Supposedly it "self heals" if you drive a nail through it.

You can get the same sort of thing in a tape, I've used a 2 inch foil faced version on the joins in my floor

[rogersmomma3]

Thank you so much! Sounds perfect for what I need. I'm really tempted to just seal the holes/joints with the tape, not do any other weatherproofing on the underside - just leave the plywood as is - and build on top. I have a very, very small budget & not a lot of time to get this done, so it seems like the thing to do.

[TNSean]

At the very least I would paint it. I think this is what I am going to do. Paint and seal holes and seam.