1972 40ft trailer

Just wondering when did older trailers from around the early 70's changed from timber to steel flooring, was there a big overlap for choices between steel or timber, some steel some timber options when buying a new trailer. I remember my old boss getting the local carpenter to fit a new floor in one of his trailers back around 1980. My trailer from 1972 has a steel floor which is stuffed, but looking at the way the floor had been fitted, it is very rough around the seams. So I am thinking that maybe the trailer came out with a timber deck which was replaced down the track with a steel deck non factory.
Either way I'm looking for some advice on timber flooring for my 40ft trailer.
I have priced up checker plate but is timber an option. So do I go up to Bunnings & get timber off the shelf or does some one out there know the best timber for the job.

Cro

I recently went through the timber exercise on my old army trailer and it is not cheap.

If you are going to spend that sort of money you must get the right timber. Standard size is 6" X 1" though there were 4" wide boards used as well. Wider the better. Tallow wood is the timber of choice because it is probably the best lasting for uncoated outdoor use. It is fairly heavy but will not twist once dried. Drying is essential as you will have gaps up to 1/2" between boards if you put wet sawn timber straight in. If they do cut the timber fresh for you you will save a lot of money by bringing it home and stacking with sticks between the rows for about 6-10 weeks out in the sun. If you are in a hurry you can pay for kiln drying. You might jag a mill that has some seasoned boards laying in their yard.

A number of standard Australian hardwoods such as Box are also OK. Ask your saw miller what he has available and Mr Google will be able to tell you if it is suitable for exposed trailer decking. They are all strong enough just some split or have gum/sap lines to spoil the surface when exposed to sun and rain for a long period.

Do not use pine, treated or otherwise, as it will warp no matter how carefully it is dried. Of course it is less than half the strength of hardwood.

For the timber you need find a saw miller. You will probably find little blokes with portable mills (they advertise on Gumtree etc) are cheaper than the big boys but not always. Go direct to the mill not a lumber yard to save money. Your quantities are enough for them to give you commercial rates.

Now the sad part. For a 40' trailer you should be well pleased if you get it under $2,500 for 6" X 1" dressed one side. If you are not too fussy rough sawn both sides might save you a few hundred but it looks crappy after going to all that effort.

Lang

I helped a mate screw down a new T&G hardwood floor in the early 70's. About 34' McGrath single axle, pretty trailer.
We cramped it as you would a domestic floor and sure enough it blew up like massive speed bumps first time it got wet.
See if you can find any old timers who know the tricks.
We obviously didn't, should have used Pt Kembla pine.

As an aside, my close bogie Freighter had a ply floor.
No idea whether it was original or not.
It did have grain chutes so perhaps the ply was easier to shovel from.

FWIW
Our ol Fruehauf 37 foot extendable had timber floor
B 4 we replaced with 1/4" CheckerPlate
the hardwood timber was length ways along the deck of 1.1/8" thick cut as Shiplap and screwd down @ every cross member
Heresa profile pic of Shiplap (take no notice of the thikness or quality of timber



Shiplap profile

cya

Yep, timber is expensive these days.
As my parents said to me and said to my kids when they wanted something:- " It doesn't grow on trees, you know" Ha Ha.

Cro you should be able to tell if it originally timber.
The combing rails will have holes where timber was bolted along the inside to seat the decking.
Likewise the cross members will have holes where a timber plate was fixed.
From memory the floor wasn't fixed to the main beams, just cross members and combing rails.
What thickness steel did you price up?
I would have thought 3mm would be heaps, could go lighter (2.5mm) for a non commercial application but I think she'd look like a hungry dog after welding.
We did 3mm on my brother in law's tray truck and he carried some horrible loads, no fails.

Back in the late 70's, bloke I was working for replace the floor in his truck using rough sawn 6" x 1" yellow box. From memory I think he didn't bolt the new timber down properly for a couple of months so it had time to weather and he could see how much space to leave between the boards to allow for swelling when wet (no more than 1/8 of an inch from memory. The rough sawn timber didn't look too bad after 6 months of use as have loads dragged on and off constantly soon knocked all the rough splinters off.

A Tongue & Groove Timber Floor was still an Option on New Freighter Trailers up until the Mid/Late 90's..
I only threw some Old Quotes out in the last 12 months (or so) that Listed all the Options ....

It was a Pretty popular option with the Steel Carters...

Ye,s good information as I want to cover a 15ft tray soon.
I'm thinking of a rough oily timber as well as I need to be able to drag heavy granite blocks over the surface. Not much point in making it shiny and pretty.
Was also thinking of using 2 heavy layers of waterproof ply (sorta like formply) so maybe the top 1 could easily be replaced as needed.
I've seen what steel trays look like after only a short while in the quarry.