Need rec's on type of floor plywood

Hey Dan,

Thanks for the advice!

Interesting question regarding changing the thickness of the floor.  I dunno.  I never thought about it.  Wouldn't 5/8" just be about what the old 1/2" was? So, maybe I could go that route? Haven't "they" reduced the thicknesses of all plywoods?  I thought back in the day when the Westerner was originally built, wasn't the wood exactly 1/2"?

My biggest concern about going thicker on the floor would be how it might impact the floor to ceiling wardrobe closet. Now I gotta squeeze it into a shorter gap.  Any thoughts? But, maybe because it's all made of wood, the  tolerances in reducing the height of the ceiling by 1/8 or 1/4 might not be an issue? 
 
Looking for a discussion.

If you are re-using the old metal siding then you better take that into consideration. Always try to keep the dimensions the same as original when possible. You can go smaller and the skin will still fit with simple trimming. But if you go larger that stuff ainna gonna stretch real easy.

Depends on how your trailer is built. If the walls are mounted to the sides and you remove all of the cabinets then yes. 

Hi Rod,

I quickly reviewed your build thread to see how the original floor was constructed. It looks like there was nothing underneath the plywood sub-floor and it laid directly on top of the metal trailer frame and wood floor joists (using home construction terms). Is that correct?

Assuming you plan to rebuild with 1/2" plywood as originally done, my concern would be where the plywood seams butt together since they are unsupported where they run horizontally between the metal and wood sub-framing they attach to. The problem I see is that 1/2" plywood is quite flexible and if left unsupported, with foot traffic, the plywood sheets will flex independent of each other at the seams, causing your flooring to lift. Does that make sense?

One easy solution would be to screw short lengths of 1x4 to the underside of the plywood along the seams between the framing members. I would also use a sheet product for the flooring rather than VCT as it will better hold up to the flexing of the thinner plywood. 

As for your plywood choices, the more plies, the stronger and stiffer. I buy 7-ply 1/2" construction plywood when I can find it, but 5-ply is what you usually find these days. You also need a smooth surface if installing your flooring directly to the plywood. Marine ply will be the strongest by far, but doesn't sound like it fits your budget. If the ABX and ACX have the same number of plies, ACX will be a bit less expensive and work just as well. If you go with ACX, be sure to undercoat the areas around the knots well as they are the most likely areas for water intrusion, although in SoCal that's not such a huge concern.

To save a few shekels you may also want to look for CCX which has one patched and sanded face that should be good enough to lay flooring over.
 

Hi Rod, Sam and I used 3/4" plywood, I don't know what kind cause I didn't ask, but it was spendy and there's no knots. We had a lot of extra left from the short section of the floor and we used that to create 8" wide pieces to go over the seam front underneath leaving just enough room for the supports the floor sits on just like they did with the original floor.

We figured we'd go a bit thicker and adjust the top of the wardrobe so we felt better about the support it will provide, but since it lasted 59 years being built like it was, there was no reason to change it. We are of course going to coat it with asphalt emulsion, but that again is just for our added piece of mind so we know the floor is protected better from water and rot than it was.

Hi Randys,

I don't think pressure treated is compatible with aluminum. I (believe) it creates a chemical reaction with the aluminum and should not be used. Someone will confirm with mor experience. Get your lumber at a lumber yard if possible. I just keep hearing a lot of bad experiences with the HD experience in this area. Cheaper yes, but not better. Pay a few extra bucks for better wood.

Rod