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How Thick Is A Caravan Floor


Spyder

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Might seem like a strange question, but what is the thickness of the wood of a caravan floor.

 

The reason I ask is that I need to secure a weatherproof box under the 'van and need to decide what length screws to use.

 

1" No 8 would be more than adequate and I cannot imagine the floor being less than 1" thick, but it's always best to check!

 

(The missus wouldn't be very happy if the screw-ends came through on the inside! :lol: )

 

No guess's please!

 

(I'll be able to check when I next go to the 'van but it's in storage and I don't really want to make a special trip just to measure it.)

 

I should have put the box size in the first posting as the question keeps cropping up. It is a 100mm x 100mm x 50mm deep electrical box (to IP44). The weight is negligable. There are already some fixed under the 'van by the manufacturer.

 

Cheers,

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Might seem like a strange question, but what is the thickness of the wood of a caravan floor.

 

The reason I ask is that I need to secure a weatherproof box under the 'van and need to decide what length screws to use.

 

1" No 8 would be more than adequate and I cannot imagine the floor being less than 1" thick, but it's always best to check!

 

(The missus wouldn't be very happy if the screw-ends came through on the inside! :lol: )

 

No guess's please!

 

No guesses? - then check in the handbook or with the manufacturer. It really doesn't matter if you use 1", 1/2" or 3/8" as the the floor is likely to be made of a plywood/styrofoam sandwich. If you look under the caravan you will see that the heaviest item screwed/rivetted to the floor are P-clips to hold cables/pipes.

 

How big/heavy is this box?

 

Mike

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Hi Spyder

 

Caravan floors are typically sandwich construction - thin plywood top and bottom with insulation in between - total thickness varies but Baileys quote 44mm for 2006 models.

 

If what you're supporting is light enough I suspect 0. 5 inch self tappers are adequate. But if it's weighty you might need to bolt through or use expanding plugs as you would for hollow doors etc.

 

Regards

 

Lunar

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Hi Spyder,

 

As Lunar stated 44mm is standard EU specification for insulation.

 

The ply skins at top and bottom of the foam are about 5mm thick. There are solid timber stiffeners bonded in at high stress points. If you can find one of these you can use reasonable length screws around 35mm.

 

They don't build them like they used to. My old Thomson Glennevis had 7/8 tongued and grooved floorboards. :)

 

Frank

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Might seem like a strange question, but what is the thickness of the wood of a caravan floor.

 

The reason I ask is that I need to secure a weatherproof box under the 'van and need to decide what length screws to use.

 

1" No 8 would be more than adequate and I cannot imagine the floor being less than 1" thick, but it's always best to check!

 

(The missus wouldn't be very happy if the screw-ends came through on the inside! :lol: )

 

No guess's please!

 

(I'll be able to check when I next go to the 'van but it's in storage and I don't really want to make a special trip just to measure it.)

 

Be very careful Spyder. As previously mentioned you will only be on the outer layer of wood (bonded). I would think a box bouncing about underneath is a recipe to help the floor to delaminate. What about making a frame across the chassis rails to hang a box on? But either way I would get Mr Sheens advice on this.

Pete

Volvo
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Guest Hobbybod

Hi Spyder

 

Caravan floors are typically sandwich construction - thin plywood top and bottom with insulation in between - total thickness varies but Baileys quote 44mm for 2006 models.

 

If what you're supporting is light enough I suspect 0. 5 inch self tappers are adequate. But if it's weighty you might need to bolt through or use expanding plugs as you would for hollow doors etc.

Regards

 

Lunar

I agree with Lunar on this. Each piece of plywood of the 'sandwich' is unlikely to be more than 4-5 mm. thick; easily estimated if you have to drill pilot holes etc. So any heavy item needs expanding/captive attatchments to the wooden ply section.

 

I have fitted a subsidiary 12V battery (~7Ahr) in a small box under the floor, in order to power my alarm system should the the main 'van battery be disconnected. (Alarm siren, which is also under the floor in the centre, will still sound if every power source in the 'van is disconnected.)

 

However, I did utilise a chassis member to help support the weight, not relying soley on screws into the floor.

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Might seem like a strange question, but what is the thickness of the wood of a caravan floor.
Avondale give a figure of 45mm for floor thickness, comprising of a 35mm Styrafoam core for insulation, bonded to a 5mm plywood sheet above and below. See picture of the floor to wall joint.

Gordon.

Caravan_floor_section.jpg

Fourwinds Hurricane 31D Motorhome. Also MGTF135 1. 8i Roadster (fun) & Volvo V70 3.2Ltr LPG (everyday car)
Unless otherwise stated, my posts will be my personal thoughts and have the same standing as any other member of Caravan and Motorhome Talk.

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Guest mr_sheens

anything of any weight fixed to the underside of the floor should not be "screwed" into the floor. as rightly pointed out the bottom layer of timber is only approx 4mm. given the weight and the movement of the caravan whilst towing, the best that could happen is it pulls the screws out and you loose what you have fixed, or the worst that could happen is it pulls the wood down causing delamination. whenever i have secured something to the underside with any weight it has been bolted all the way through with large washers under the head of the bolts to spread the load.

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Thanks for the replies so far . .. I think some have mis-understood what I am screwing to it. My fault, I should have said in the beginning!

 

It is a weatherproof electrical box, 100mm x 100mm x 50mm deep. Plastic with a screw on sealed lid. The weight is negligable, considerably less than a bag of sugar!

 

So, 5mm of plywood would be more than enough.

 

(I have noticed that some are already attached by the manufacturer.)

 

Again, thanks for the replies!

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Might seem like a strange question, but what is the thickness of the wood of a caravan floor.

 

Hello, I can only reiterate Mike's comment : how big/large is this box ? Just a thought, have you thought about any reduction it might cause in ground clearance ? :huh:

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i am putting a safe in the van this weekend i have had a plate made the same size as the safe with the same size holes,reading this article i just wondered the thickness in inches my bolts are 2inches long have i got the right size thanks in anticipation dave

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i am putting a safe in the van this weekend i have had a plate made the same size as the safe with the same size holes,reading this article i just wondered the thickness in inches my bolts are 2inches long have i got the right size thanks in anticipation dave

 

Based on the post Gordon made, if the floor is 45mm thick, that leaves you only 5mm to play with. Depending upon the thickness of the safe, I would think 50mm (2" in old money) bolts may be a bit short.

 

Might be worth getting 55mm or 60mm and cutting them down if necessary?

 

I'll let you know the floor thickness of an Adria tomorrow as I'm going to the storage site to do my job.

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Well having been to the site and done my little job I can confirm that the floor of the Adria is as described above. A top and bottom of plywood sandwiching Styrafoam, approximatley 2" thick altogether.

 

I was comforted to find that Adria had already attached two electrical connection boxes, so I removed the screws and found they were about No8 x 3/4 and directly into the plywood. I then used the same size screws to attach my electrical connection box!

 

So again, thanks for the info!

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spyder thanks for the info. one other point is it worth covering the plate with mastic befor putting it to the bottom floorthanks once again for your help dave

 

Personally, I would, you can buy caravan mastic from dealers, not sure of the difference though.

 

The way I see it is that it cannot do any harm and can only do good in preventing any risk of moisture ingress!

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