Thread: 7x4 box trailer walls

Billy.
Firstly,
The decision for the floor mainly comes down to what you're carrying in the trailer. A load of dirt or gravel that requires shoveling out can badly scratch or damage anything other than a steel/aluminium floor. And checker plate is a pain to scrape/sweep out.

If you're east of the CBD, go and see Melbourne Trailers, they have ready made, folded sides off the shelf. By the time you muck around with building a frame and cladding it, it would probably work out cheaper and less time consuming to get the prefolded sides and tailgates.

thanx for the info Yonnee

Ive decided to go with smooth plate for the floor & ordered the walls/tailgate from Melbourne Trailers (who were extremely helpful btw)

It was mentioned that it would be easier to put the floor in first then sit the walls on top... I was thinking long term - when it comes to replace the floor it would be easier to just cut it out rather than having to remove the walls first as they'd be sitting on the floor

Would it be better to put the floor in first, or the walls then cut/weld the floor to suit?

Any tips or comments appreciated,
billy

I'm wondering who gave you that info? They've obviously never had to remove a rusty trailer floor.
The normal practice is to assemble the frame, attach the uprights in each corner, then fit the sides, then the floor.

A tip for you;
Get yourself a tin of bitumen paint, and coat any surface of the chassis, the floor and the sides that get hidden once welded in place. Spending a little time and some cash doing this now will substatially increase the life of the floor and sides of the trailer. Usually the first place a trailer will rust out is where there is no paint, but moisture can still reach.

And if you really want to get fussy, fill the gaps of the joins with paintable caulking, and you'll increase the life of the trailer even more.


Yonnee.

I built my trailer 9 years ago now. It has a 15mm exterior ply floor, glued to the framing with sikaflex. It gets a coat of deck oil once or twice a year. It sits out in the tropical weather with 2m+ of rain a year and sunlight so fierce that the UV will burn your skin in a few minutes. I thought I'd be replacing the floor every 4 years or so but I'm still on the first one. This trailer gets constant trade use, often getting sand/gravel premix in it plus a mixer and being used for mixing concrete. The ply is getting a bit ratty near the tail gate but isn't lifting up in large splinters yet. I think it's worth considering a ply floor.

Mick

I've got no problem with a ply floor, however, you'd have to be fairly vigilant about keeping it oiled, as you have, as well as storing the trailer so that water did not sit in it. If neglected, a timber floor would deteriorate far quicker than a steel floor.

thankyou both for the tips/info Mick & Yonnee

Originally Posted by Yonnee

I'm wondering who gave you that info? They've obviously never had to remove a rusty trailer floor.

..... thats what I was thinking... Im new to building/modifying trailers & they seemed to know what they were talking about

Originally Posted by Yonnee

A tip for you; Get yourself a tin of bitumen paint

yes... Ill definitely do that to the underside & bottom of floor

Originally Posted by Yonnee

...fill the gaps of the joins with paintable caulking, and you'll increase the life of the trailer even more.

excellent idea... also keeps all the muck & little bits of dirt out if the joins

Originally Posted by journeyman Mick

I built my trailer 9 years ago now. It has a 15mm exterior ply floor, glued to the framing with sikaflex. It gets a coat of deck oil once or twice a year

nice idea... I might get some ply to get me going until ready to do the steel - at least that way I can start using the thing

cant wait to get started,
billy ;-)

Originally Posted by yonnee

The normal practice is to assemble the frame, attach the uprights in each corner, then fit the sides, then the floor.

what are the uprights made out of.... just 35x35x3mm angle iron or something like that?


billy

Rather than ply I've used 16mm formply in my trailer. I screw from underneath so the surface has no raised bit or holes for water to get in and seal around the edges. Formply is fully waterproof, surfaces are laminated and take quite a bit of abuse with sand, gravel and assorted other loads such as mixed rubble, green waste etc. being removed using shovels rakes and forks. a 2400x1200 sheet is around $70 to $90 (can be dearer!). I've used the red stripe, but either would do. Slightly heavier than checker plate, but does not bend or warp is resilient to loads being dropped in from bit of height and wears well IMO. Like all floors it will not like wet organic matter sitting in it for very long or water around edges in pools. I've tried plain steel, steel checkerplate and aluminium checkerplate and the formply is best for my mixed uses.

Originally Posted by billymm

what are the uprights made out of.... just 35x35x3mm angle iron or something like that?

billy

If you were wanting to attach timber or formply sides by bolting them on, then angle is good. But the steel sides are usually welded to RHS offcuts from your chassis.