DIY horsebox floor replacement

[Matafleur]

I'm hoping that the great and good of HHO can help with a little combined wisdom. I have a Mk1 Renault Master that needs a new floor, a hole has developed in the granulistic and the ply beneath is clearly rotten. It has a full metal platform chassis that the ply floor sits on top of. This looks very sound for the most part (from underneath) but there is a small spot that will possibly need welding which we will check when the floor is fully removed.

The rough plan is to use phenolic ply board covered with rubber matting but I'm not sure how to go about fixing everything or what thickness to use. I had a quote from a garage who said they would use 18mm board and 12mm rubber - does this sound about right? And is phenolic ply heavier then marine ply (which I think is what it currently has)? Weight is obviously a consideration for this lorry and I'd prefer not to lose any payload if possible.

I'd prefer rubber mats to granulistic this time as it's easier to check the floor but I am a bit worried about the mats moving... Should they be fixed down somehow? And do you fill in the dips in the chassis with anything? or does the ply just sit nicely on the raised parts?

How do you fix the ply to the chassis?

Sorry for all the questions, I've been quoted £575 + vat (a bit more if welding needed) by the garage which I don't think is that bad but the VAT is the killer! If we are struggling it may have to go in to be finished off but if we could get most of the way ourselves it may save us some money.

My family are farmers so we have access to the kit we should need, just need to get materials.

Any advice welcome

 

[cundlegreen]

I've built/ converted three lorries now, and floors are a priority. All of my lorries have been delivery box vans or curtainsiders, so have a 3/4" hardwood floor down already. I then put two layers of hardwood ply down, 1/2" thick each, and I tend to layer them a different way each layer if you understand what I mean. They are nailed down with small galvanised nails, then a rubber floor is placed over the top. I find that if you do get rot, which you shouldn't with good ply, you can then just lift and replace the top layer of board. I've only once had to do this in about 25 years of having lorries, and my last container build, I reused the ply floors because they were in perfect order. Exterior/marine ply isn't always very good. You are looking for hardwood ply, and as many layers as possible. I was told to get an offcut, and leave it in the waterbutt for a week. You soon find out if the ply is up to the job. As you are attaching to the chassis, I would bolt through using nylock nuts so it doesn't undo. There is also a self tapping type of screw with a wedge shape at the bottom. I used these to put my board onto the ramp metal frame, but you have to drill pilot holes first. Hope this helps.

 

[Matafleur]

Thank you, very helpful. It would be phenolic ply (buffalo board perhaps?) that we'd be using rather than marine ply, I'm told that is better.

 

[cundlegreen]

Thank you, very helpful. It would be phenolic ply (buffalo board perhaps?) that we'd be using rather than marine ply, I'm told that is better.

Yes, I've used that here for replacing stable kicking boards. Agree its much better, but my stuff was quite thin, and small strips approx 12" wide. Is that what you are thinking, or have you a bigger size. Why don't you go for a checkerplate floor covered in rubber? I'm sure it would be lighter than the buffalo board, and stronger. The rubber matting weighs a lot, so you need to work out weight for a 3.5 ton.

 

[Matafleur]

Yes, I've used that here for replacing stable kicking boards. Agree its much better, but my stuff was quite thin, and small strips approx 12" wide. Is that what you are thinking, or have you a bigger size. Why don't you go for a checkerplate floor covered in rubber? I'm sure it would be lighter than the buffalo board, and stronger. The rubber matting weighs a lot, so you need to work out weight for a 3.5 ton.

I did wonder about the checker plate and the garage said that they had looked into it but on balance thought the ply would be better. I've also spoken to the dealer I bought it from and she said she usually preferred to use the ply, although nothing wrong with the checker plate as such. I'm hoping the matting won't be much heavier than the granulistic that is down at the moment...

I was hoping for large sheets of phenolic but tbh I haven't looked into it that closely yet.