material for crawlspace door

[vavet]

I need a new crawlspace door. The old one was made of plywood and it's rotten. Not sure if it was exterior grade plywood when it started or not. It's at least 14 years old.
The door needs to be about 25-1/2 by 24-1/2.
I don't have much need for a sheet of exterior grade plywood, so I hate to spend $40 on a full 4x8 sheet. The project panels they sell in the big box stores are usually 2x2 or 2x4, so I'd be leaving it a bit small if I tried to do that.

I guess my questions are:
1. Do I need pressure treated wood or exterior grade plywood? Can I get away with untreated plywood if I paint it?
2. Could I use 1x or 5/4 exterior lumber with a backer strip to tie all the pieces together? If I did that, would I/should I leave a gap between the pieces like you do with a deck? Is that to allow for expansion with increased humidity? Or is that so water can flow through easily?

 

[kbs2244]

Number 2 and done tight
(unless you have water flowing through the doorway)

 

[OccupantRJ]

I am making mine out of stainless steel sheet. I cut down a standard steel frame to fit, then found the piece of stainless in front of my house. It appears to be a commercial ice maker door that had blown off a vehicle. The frame may rust, but the door won’t.

 

[matt_i]

I'd just paint a new standard sheet cut-to-fit unless you want to knock this project off the list. If you want the latter then I'd invest in the treated ply or the stainless sheet metal as suggested.

If there was an opportunity to buy treated ply in a low-cost 24" square I think you could probably modify the frame to take up 1-1/2".

 

[fasteddie]

If I were doing it I would be using 3/4" ext ply and clad the face and around the edges with aluminum white coil.

 

[OccupantRJ]

A countertop shop often has sink cutouts of solid surface (Corian) material that get piled up. Lots of colors. A friend gives me some when I want it for small projects. I am not sure how it holds up in direct sunlight, but I had a shelf for a golf cart battery charger made out of it under my carport for years. My outdoor pump wellhouse has a granite top, and is used for a coffee table when using the lawn chairs. Just gotta be creative with available materials.

 

[joe49]

Home Depot
https://www.homedepot.com/p/1-in-x-5-1-2-in-x-6-ft-Pressure-Treated-Pine-Dog-Ear-Fence-Picket-102560/202319053
Cheap way to build things.

 

[driftpin]

Do you need ventilation in the piece? The H. Depot fence boards joe49 mentioned, and some fine screen stapled to them, after painting, should last a long time. Are you planning to hinge it? Through-bolt it rather than using wood screws.

 

[joe49]

https://www.hunker.com/12618331/how-to-build-a-z-brace-door

 

[gahrajmahal]

If I remember right mine was just made from 3/4 tongue and groove oak flooring with two cross pieces hanging on the underside.