Motorhome floors (2 Viewers)

Jun 19, 2014
331
513
Wimborne
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Adria Coral+ 670SL
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No longer a newbie
Does anybody know anything about the floors used in Motorhomes?

I ask because I want to fit a different table to my 2015 Adria, and need to fix it to the floor. I was going to bolt it through, but there is a chassis member in the way, so I am thinking about self-tappers, or threaded inserts.

If I drill, and break through the floor I can seal it with mastic where I can get to it, but not where I can’t, for example in the upside-down top-hat section of the chassis.

So to crystallise my thoughts, does anybody have an idea of the likely thickness (not keen on drilling a test hole), and what material? In a mock up I have found a conventional mate machine screw driven into heavy marine ply more than strong enough, but I fear that even though the loads are light they may be too much for lightweight boards.

My very last resort would be to bond the base of the table to the floor, or am I wrong to be reluctant to do that?

Any insight will increase my knowledge 100%, so thanks.
 

Mikey RV

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Mar 7, 2010
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Why do you need to bolt it to the floor. We have removed ours and I bought a Fammia tripod leg and just attached the table top to that. Which means it is lighter, and I can put it exactly where I want it, including outdoors. If we don't want the table up its easy to store away and you have more room.
 
Jul 5, 2013
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I guess the floor will be composite sandwich. Ali or GRP outer skin, thin ply inner skin and held together with bonded foam insulation. Can't see self tappers or threaded inserts working. Normally drill and bolt through with spreader plate underneath to prevent bolt and washer pulling through the ali/GRP.
 
Apr 27, 2008
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Eastbourne East Sussex
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Hymer low profile
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Since 1972
If its already got a table why not see how thats fitted. Mine (Rapido) was just screwed with ordinary woodscrews, so thats how I fixed the smaller replacement.

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Tootles

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I wanted to do that for Les but she poo pooed the idea..:xwink:
It works quite well, Pete. With a drain hole as well, it means that she can 'go' whilst we are 'going', if you see what I mean. :xsmile:

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Tootles

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Not sure this is helping to answer @chuns original post but sure brings it down to floor level if nothing else!
It might make him laugh, which, after all, is partly what *FUN* is all about.......:xgrin:

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DuxDeluxe

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Does anybody know anything about the floors used in Motorhomes?

I ask because I want to fit a different table to my 2015 Adria, and need to fix it to the floor. I was going to bolt it through, but there is a chassis member in the way, so I am thinking about self-tappers, or threaded inserts.

If I drill, and break through the floor I can seal it with mastic where I can get to it, but not where I can’t, for example in the upside-down top-hat section of the chassis.

So to crystallise my thoughts, does anybody have an idea of the likely thickness (not keen on drilling a test hole), and what material? In a mock up I have found a conventional mate machine screw driven into heavy marine ply more than strong enough, but I fear that even though the loads are light they may be too much for lightweight boards.

My very last resort would be to bond the base of the table to the floor, or am I wrong to be reluctant to do that?

Any insight will increase my knowledge 100%, so thanks.
I think that with a 2015 van that Mikey RV's idea might be the best for several reasons; warranty, you can move it if not quite right and options to use outside.

Apologies to @Tootles for inconsiderately dragging this thread kicking and screaming back on to topic........
 

Lenny HB

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Sorry to be serious, floor construction is likely to be a sandwich of 2mm ply on either side bonded to either 25 mm or 35mm polystyrene or styrofoam.
 

Popeye

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There is really no need to drill the floor to find out how thick it is just measure it.

It's even easier these days with highly accurate cheap laser levels.
 
Last edited:
Jul 5, 2013
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Sorry to be serious, floor construction is likely to be a sandwich of 2mm ply on either side bonded to either 25 mm or 35mm polystyrene or styrofoam.
I think Adria use GRP on the underside. They certainly did with my 2008 coachbuilt.

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OP
OP
Chuns
Jun 19, 2014
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Thanks for all the helpful thoughts, and the amusing drift off topic.
 

Terry

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Dec 27, 2007
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Hi I don't know about your model floor but you have obviously done some investigating yourself-- Once you have screwed your table down (or bolted) remove the screws and fill holes with Puraflex 40 or Sikaflex then replace the screws in the holes -I personally would use TEC bolts but that's just my liking
terry
 

Bailey58

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Why do you need to bolt it to the floor. We have removed ours and I bought a Fammia tripod leg and just attached the table top to that. Which means it is lighter, and I can put it exactly where I want it, including outdoors. If we don't want the table up its easy to store away and you have more room.

you could glue and screw using sikaflex or similar.

I guess the floor will be composite sandwich. Ali or GRP outer skin, thin ply inner skin and held together with bonded foam insulation. Can't see self tappers or threaded inserts working. Normally drill and bolt through with spreader plate underneath to prevent bolt and washer pulling through the ali/GRP.

If its already got a table why not see how thats fitted. Mine (Rapido) was just screwed with ordinary woodscrews, so thats how I fixed the smaller replacement.

Sorry to be serious, floor construction is likely to be a sandwich of 2mm ply on either side bonded to either 25 mm or 35mm polystyrene or styrofoam.

There is really no need to drill the floor to find out how thick it is just measure it.

It's even easier these days with highly accurate cheap laser levels.

Hi I don't know about your model floor but you have obviously done some investigating yourself-- Once you have screwed your table down (or bolted) remove the screws and fill holes with Puraflex 40 or Sikaflex then replace the screws in the holes -I personally would use TEC bolts but that's just my liking
terry

Don't know what Fun's coming to, all these serious answers spoiling a good thread. :shake:
 

Judge Mental

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how old is the van as drilling through structure can be used as an excuse it invalidate warranty. With some vans only dealers are allowed to drill the structure..if out of warranty no problermo

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OP
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Chuns
Jun 19, 2014
331
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Wimborne
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Adria Coral+ 670SL
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An update for those who kindly showed an interest, and gave opinions...

There is a double floor where I want to fit the table pedestal, made of 15mm ply. Although soft and light, this will easily accept the likely loads it will endure, the mountings are 8mm, spaced at around 250mm diameter.

Getting to it is another matter - I pulled the fresh water tank out, only to find supportive webs in the way, so no backing plate, or nuts and washers. However I found some 8mm spring toggles, like you use with plasterboard, and they should suffice.

I'm going to dwell on it for a while.
 
OP
OP
Chuns
Jun 19, 2014
331
513
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Adria Coral+ 670SL
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It seems my iPad post didn't work, apologies if I end up double-posting here.

An update for those who kindly showed an interest, and gave opinions...

There is a double floor where I want to fit the table pedestal, made of 15mm ply. Although soft and light, this will easily accept the likely loads it will endure, the mountings are 8mm, spaced at around 250mm diameter.

Getting to it is another matter - I pulled the fresh water tank out, only to find supportive webs in the way, so no backing plate, or nuts and washers. However I found some 8mm spring toggles, like you use with plasterboard, and they should suffice.

I'm going to dwell on it for a while.

Cheers

Peter
 
OP
OP
Chuns
Jun 19, 2014
331
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Adria Coral+ 670SL
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Damn. Sorry.

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Terry

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Hi Peter try some thick (fat) gauge screws first ///// you have to make big holes for toggle screws
Terry
 
OP
OP
Chuns
Jun 19, 2014
331
513
Wimborne
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Adria Coral+ 670SL
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Yep, good thought, Terry, however the ply, unlike the marine ply I am used to, is very light (though stiff) - the plies seem to be of a soft and light wood, somewhere between balsa and birch. I already have ripped a fitting out of a vertical wall just by inadvertently leaning on it! I don't think 15mm will give enough meat for those types of fastening.

Cheers,

P
 
Sep 25, 2009
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Just a thought.is there room to get a piece of thicker ply between the floor space to strengthen the area you are screwing to.

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