Waterproofing plywood for trailer floor/deck use

[mark roberts]

To be honest I wouldnt have used ply at all, even WBP ply wont last long. It might seem strange but OSB is great stuff, it has that much glue in it. I've got some sat in the garden for a couple of years and its still good.

 

[Smouser]

There is so much conflicting information and opinions online (even just on this thread). It is actually very hard to decide what to use/what the best method is.

For me, it is now a wait and see how long it lasts so I can build up my own 'data'.

I might post back in a years' time saying it all failed or I might not be back for 10 years. Who knows.

 

[addjunkie]

There is so much conflicting information and opinions online (even just on this thread). It is actually very hard to decide what to use/what the best method is.

For me, it is now a wait and see how long it lasts so I can build up my own 'data'.

I might post back in a years' time saying it all failed or I might not be back for 10 years. Who knows.

Just sell the trailer for an inflated price to some one and go buy a better one, with the origional floor

 

[Smouser]

No way! It is all sorted now. Brakes, brake cables, U bolts, suspension brackets, brake breakaway cable, all new electrics, new wheels and tyres. It is like Trigger's broom!!!

 

[Onoff]

It might seem strange but OSB is great stuff, it has that much glue in it.

Our dormer flat roof was put on in 1987. It was 18mm marine ply. I know this as there's a folder of old bills came with the house. Though the felt is shot, the ply has "saved" the roof. The sides of the dormer too are ply clad before felt, battens and tiles.

On the kids Wendy house I used 18mm OSB3 and on the tree house 25mm OSB3.

I think I "killed it" on both by painting it with No Nonsense Wood Treatment. On the treehouse I covered it with a lorry siding that I glued on with spray contact adhesive.

https://flic.kr/p/UFFtUn

I however didn't get around to putting any retaining, edge trims on Consequently the wind got under and took the green cover off. No worries I thought, I've a bit of time to get it back on.....

On the Wendy house I just had a cheap tarp over it before I felted. Which I never got round to...

Pretty quick though I think it upset the glues in the OSB. It's now like Weetabix on both.

 

[Farside]

Pretty quick though I think it upset the glues in the OSB. It's now like Weetabix on both.

Yep, different grades of that stuff are available.
I've seen some OSB that stands up to just about anything for a looooooooong time, and others that fall apart on one wetting.
Trouble is, you don't know what you're getting from a general supplier, until it's too late.

 

[charlysays]

recently bought a bit of a Lemon Ifor Williams flatbed trailer.
I did not spot half the problems it had when I bought it, and I definitely overpaid

I am replacing the bump stops, suspension bushes, and brake cables and re-doing all the electrics to name a few.
There is no point crying over split milk, and all I can do is fix the issues/replace the knackered parts, which bring me to the floor/deck of the trailer.
The floor was completely rotten (hidden by some aluminium treadplate) and it needs replacing now.

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The perfect solution for the floor would be to buy some buffalo board / phenolic plywood BUT funds are tight with the extra expenses on the trailer and I have got some free new 'normal' (not marine) plywood sheets I can use.
While I am fully aware that they will never last as long as the 'proper' stuff I do want to waterproof them/coat them with something which should give me a few years of use before I need to replace them.

What product could I use to waterproof the boards?
I am considering something like Everbuild 908 DPM or Everbuild 905 All Weather Roof Coating which can be bought for between £22 - £25 for 5 litres

View attachment 424899View attachment 424901

The treadplate will go back on top of the plywood so the coating does not necessarily have to be hard-wearing/withstand normal trailer use.

Has anybody had any experience with those products or can suggest an alternative?

Thanks in advance!

Personally I would look at Marine products and techniques as it'll be constantly soaked.
Coat the ply thoroughly on all sides with an epoxy like west system 105/205, two coats spread with a squeegee, ideally coat any bolt holes too. Use large washers countersunk if necessary so the ply doesn't get damaged through compression. This is a really good start and will drastically increase the lifespan of the ply especially if the chequer plate is taking all the abrasion. If the ply is taking abrasion you could laminate a fine glass cloth over the ply with more epoxy. With most commonly available ply you'll probably need to add some coloidal silica to some epoxy to fill voids in the edges of the ply. Unless you pay like £130 a sheet for proper marine ply (such as supplied by Robins in Bristol) there are always voids visibly in the edges.

 

[Smouser]

Personally I would look at Marine products and techniques as it'll be constantly soaked.
Coat the ply thoroughly on all sides with an epoxy like west system 105/205, two coats spread with a squeegee, ideally coat any bolt holes too. Use large washers countersunk if necessary so the ply doesn't get damaged through compression. This is a really good start and will drastically increase the lifespan of the ply especially if the chequer plate is taking all the abrasion. If the ply is taking abrasion you could laminate a fine glass cloth over the ply with more epoxy. With most commonly available ply you'll probably need to add some coloidal silica to some epoxy to fill voids in the edges of the ply. Unless you pay like £130 a sheet for proper marine ply (such as supplied by Robins in Bristol) there are always voids visibly in the edges.

If you go through all of that effort and cost, it will be better to just buy phenolic plywood/buffalo board.

My solution cost £100 (I got the plywood free) and I hope it will last for a few years.

All we can now do is wait and see how effective/ineffective the wood treatment and bitumen paint combination performs.

 

[charlysays]

If you go through all of that effort and cost, it will be better to just buy phenolic plywood/buffalo board.

My solution cost £100 (I got the plywood free) and I hope it will last for a few years.

All we can now do is wait and see how effective/ineffective the wood treatment and bitumen paint combination performs.

I think buffalo board is about £120 a sheet? It looks like you'd need 3 sheets so around £350 of buffalo board.
If your ply was free, as a boat builder, my quick job preference would have been £50 on a 1.2kg west epoxy pack and coat the hell out of the ply and the edges (it's a quick job done with a squeegee on some trestles) and just fit the ply in its epoxy coated form. Seal the bolts thoroughly as they go in with sikaflex ebt. Would likely last almost as long as buffalo board (if the chequer plate is taking the abrasion) and a good saving over both your solution and a huge saving over buffalo board.
Your solution will work pretty well though I reckon, it's just that nowadays epoxies are a good one stop solution for most coatings and the building trade doesn't seem to have caught up that well and is still selling stuff like wood hardeners, polyester fillers etc for wood and epoxy is just so much better.

 

[redlig]

I'm about to rebuild my 15cwt braked ex trials car trailer into a 2 bike / quad /garden trailer and after reading this I think i will just use 2nd hand scaffold boards they should last me out ,hopefully. Should be fun !

 

[addjunkie]

I'm about to rebuild my 15cwt braked ex trials car trailer into a 2 bike / quad /garden trailer and after reading this I think i will just use 2nd hand scaffold boards they should last me out ,hopefully. Should be fun !

New ones are very little more!

 

[8ob]

I'm about to rebuild my 15cwt braked ex trials car trailer into a 2 bike / quad /garden trailer and after reading this I think i will just use 2nd hand scaffold boards they should last me out ,hopefully. Should be fun !

I went with scaffold boards, I drowned them in creosote( the proper stuff) and gapped them to allow for expansion when wet, I allowed 6mm between boards and as we speak they gaps are closed up.

Bob

 

[redlig]

I went with scaffold boards, I drowned them in creosote( the proper stuff) and gapped them to allow for expansion when wet, I allowed 6mm between boards and as we speak they gaps are closed up.

Bob

Thanks for tip .

 

[lexi]

Trailers are a nightmare! I have a few for boats. Towing is a nightmare too!

 

[Migmac]

Trailers are a nightmare! I have a few for boats. Towing is a nightmare too!

Towing is easy anyone can do it , reversing is the tricky bit for many

 

[addjunkie]

Towing is easy anyone can do it , reversing is the tricky bit for many

Just takes practice, and a big space to learn in……..

 

[Migmac]

Just takes practice, and a big space to learn in……..

You’d think so, I have horse people next to my beat. Plenty of room there to play with the Disco and trailer. She still cant reverse a trailer. You meet her on the road and she freezes. Ive made her go back a couple of times, it’s hilarious

 

[slim_boy_fat]

....Ive made her go back a couple of times, it’s hilarious

You're a very bad man.... That said, I've done similar with folk driving rental motor homes in the past.

I know a chap who managed to get a tree between a tractor and big trailer. Took some extricating as the trailer was loaded with tons of riddled topsoil and the tree was against the drawbar - to this day I still have no idea how he did it..... Seems like a special kind of skill.

 

[Smouser]

I can reverse an artic truck (easier than car trailers imho) but I do struggle to reverse mine onto the drive. The clearance between the gate posts are just too small. You basically have to be perfectly aligned to get in in.

I can't just reverse it in straight unfortunately.

 

[Migmac]

I can reverse an artic truck (easier than car trailers imho) but I do struggle to reverse mine onto the drive. The clearance between the gate posts are just too small. You basically have to be perfectly aligned to get in in.

The man that taught me the basics, always said a bigger trailer is easier to reverse. Little car trailers, ones like Halfords sell, are awkward things. You can’t see them most of the time. Night time reversing can be a pain, most pickups only have one reverse light, we’ve added two reverse/ work lights to my pickup and the new trailer has reverse lights on it.