Car Trailer - Material for deck

[edwagon]

I am nearly finished building another car trailer - internal deck size 4500x1900

I am stuck on what to make the deck out of - I usually use steel tread plate and weld it on but am looking at other options, partly because I am looking at having a full deck so its useful for carting other stuff.

I need to make a decision before it goes for galvanizing so I can cater for fixing whatever I end up using

Cross beams are 50x25 RHS on edge, with 525 between spans

I have looked at using 20mm T&G flooring ply, but will require extra support on the edges == weight and cost and lots extra work

I am leaning towards using boards like a truck deck, but have not had good luck finding suitable timber.
How thick would it need to be?
180x42mm T&G Retaining wall timber is well priced - kinda half joking but do I just use that? Anything wrong with it?

Anyone got any ideas?

[touge_ae101]

decking timber always works well. give it a stain and it looks a million bucks + cheap as chips..

or you can get a grooved & stained ply (can't remember the name dammit) that looks really good on trailers and is grippy.

[85AW20v]

Be aware that any solid timber like decking or T&G retaining wall decking will shrink as it dries whereas ply is a lot more stable and won't move. I'd still go with the treadplate welded on before you send it for galvanising.

[wde_bdy]

Weld treadplate on, add plywood down the middle if you need to carry stuff other than cars.

Callum

[RobertC]

how much support is currently there?

this looks nice and comes in 12mm, 18mm and 28mm.

its called brownwood ply

[edwagon]

how much support is currently there?

Ladder frame 100x50 sides and 50x25 cross beams, 525 gap between each
The front and rear have a 60mm flatbar ledge for the deck to sit on.
There is no support between the beams on each side where it meets the sides, so if I use ply I'll have an edge hanging in midair, unless I continue the flatbar ledge around the whole frame - ugh