Spongy floor (1 Viewer)

Apr 18, 2013
118
173
Nuthampstead
Funster No
25,596
MH
Rv
Exp
since 2013
Hi, would appreciate any comments on the above. Appreciate its probably been covered before, but would still like opinions.
I have a spongy floor, an area of around 1m square, in a RV.
Its always been a bit soft, but has got progressively worse over a number of years.
I can`t see any leaks, so I think the ply may have just delaminated over time.
I was going to peel back the vinyl, cut out the ply, and see whats required. But, having had a quick look on Youtube, it seems there are other methods of repair, such as epxoy or single part adhesives, and dowels.
Any thoughts on what be the best action to take ?
 

TheBig1

LIFE MEMBER
Nov 27, 2011
17,160
40,923
Dorset
Funster No
19,048
MH
A class
Exp
many many years! since I was a kid
Cutting out and a full repair is a much larger job than you might expect. A delamination kit, injecting resin is by far the least destructive method. One thing that some neglect to do is add a sheet of polythene over the area before adding weight to any bulging area. This prevents any seepage from gluing the weights (bricks are ideal) to the floor
 
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OP
neilydun
Apr 18, 2013
118
173
Nuthampstead
Funster No
25,596
MH
Rv
Exp
since 2013
Thanks for the replies.
Its a Gulfstream Sun Voyager.
Has anyone tried the single part adhesives ?
I presume its an expanding PU adhesive like Gorilla glue.
Just to check, with this type of repair, drill through the top sheet of ply only, then inject, dowel and weight down ?

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TheBig1

LIFE MEMBER
Nov 27, 2011
17,160
40,923
Dorset
Funster No
19,048
MH
A class
Exp
many many years! since I was a kid
Thanks for the replies.
Its a Gulfstream Sun Voyager.
Has anyone tried the single part adhesives ?
I presume its an expanding PU adhesive like Gorilla glue.
Just to check, with this type of repair, drill through the top sheet of ply only, then inject, dowel and weight down ?
you are correct, drill multiple uniform grid of holes 20mm into floor. inject resin and immediately plug with dowels. Then lay plastic sheet and weight down to prevent a bulge. 48 hours then lift plastic and trim any protruding dowels

Can be a messy job if you are not careful
 
Feb 2, 2019
1,034
2,407
Norfolk
Funster No
58,334
MH
Pilote G740C
Exp
2018
Buy one of the kits off ebay with the resin, syringe and dowels. Follow the instructions and after an hour or so you'll have a floor that once dried, will be rock solid.

I did it to a 1975 caravan that had a spongy floor and it turned out great. No more movement or bounce and a cheap easy fix too.

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Oct 25, 2018
14
10
Funster No
56,919
MH
Pilote P740FC
Exp
14 years
I privately purchased a 2019 Pilote last November only a few days following its 2nd habitation check at the Dealership where it was first purchased by the previous owner. We bought the vehicle on the basis that the vehicle would be in tip top condition prior to purchasing.

On our first trip we noticed that the floor in the kitchen area was very spongey. Fearing the worst, we thought we had a water leak. This was not the case and we had the floor inspected by a registered motorhome service engineer who inspected the floor and concluded that there were no damp issues but the floor was badly delaminated. In a vehicle just over 2 years old, he was surprised how this could have occurred and even more surprised that the Dealership had passed it as ok.

Following numerous calls querying the Dealership's inspection and contacting the head of Pilote in the UK, I am left with statements telling me I am out of Warranty and still left with this problem. Not sure of the next step but in the meantime I have covered the kitchen area with a 4 mm aluminium plate to limit any more damage to the floor.
 
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OP
neilydun
Apr 18, 2013
118
173
Nuthampstead
Funster No
25,596
MH
Rv
Exp
since 2013
Before I start drilling holes in the floor, is there any reason that the floor build up would be different on an american ?
 

POH

May 29, 2018
1,107
803
Funster No
54,135
I privately purchased a 2019 Pilote last November only a few days following its 2nd habitation check at the Dealership where it was first purchased by the previous owner. We bought the vehicle on the basis that the vehicle would be in tip top condition prior to purchasing.

On our first trip we noticed that the floor in the kitchen area was very spongey. Fearing the worst, we thought we had a water leak. This was not the case and we had the floor inspected by a registered motorhome service engineer who inspected the floor and concluded that there were no damp issues but the floor was badly delaminated. In a vehicle just over 2 years old, he was surprised how this could have occurred and even more surprised that the Dealership had passed it as ok.

Following numerous calls querying the Dealership's inspection and contacting the head of Pilote in the UK, I am left with statements telling me I am out of Warranty and still left with this problem. Not sure of the next step but in the meantime I have covered the kitchen area with a 4 mm aluminium plate to limit any more damage to the floor.
Hi Rob, we have a 2021 evidence and have the same problem in the same area looks like they a problem with the floors, but it is still under warranty thank god, dealer has tried to fix but broke 3 needles so it's going back to France to be sorted early Oct, apparently they are taking all the floor up that means all kitchen , seats and fridge out and putting a new one in ,all in 2 weeks?? Hope you get yours sorted soon (y)(y)

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John Barrett

Free Member
Jan 19, 2020
1,963
18,442
Hamble, Southampton.
Funster No
68,164
MH
One Eyed in Hamble!
Exp
Since 2012
I had the same problem with our 15 year old caravan. I Used some 6 minute urethane glue and 10mm dowels at 100mm intervals and the floor was soon as good as new. Make sure that the dowels are long enough as the kits you buy supply 30mm, not the 40mm required on most floors!
 
Oct 25, 2018
14
10
Funster No
56,919
MH
Pilote P740FC
Exp
14 years
Hi Rob, we have a 2021 evidence and have the same problem in the same area looks like they a problem with the floors, but it is still under warranty thank god, dealer has tried to fix but broke 3 needles so it's going back to France to be sorted early Oct, apparently they are taking all the floor up that means all kitchen , seats and fridge out and putting a new one in ,all in 2 weeks?? Hope you get yours sorted soon (y)(y)
Thanks John, hope so. The engineer that looked at the problem said the only way to fix it properly would be to remove all the furniture to replace that section of floor and would cost a few thousand pounds.
Just annoyed the Pilote dealership didn't pick up the problem prior to our purchasing it.
 
Oct 25, 2018
14
10
Funster No
56,919
MH
Pilote P740FC
Exp
14 years
Apologies POH
I have called you John by mistake.
You don't happen to know what the Dealership were trying to achieve when they broke 3 needles?
Cheers Rob

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POH

May 29, 2018
1,107
803
Funster No
54,135
Apologies POH
I have called you John by mistake.
You don't happen to know what the Dealership were trying to achieve when they broke 3 needles?
Cheers Rob
Hi Rob, you can call me anything it's Friday :rofl:, in answer to your question they we're trying to fix the floor in my van apparently they drilled holes underneath and insert the needles in put the resin in, but as I said they broke 3 , so it goes back in October and pilote will fix it šŸ¤žšŸ¤ž
 
Oct 25, 2018
14
10
Funster No
56,919
MH
Pilote P740FC
Exp
14 years
Hi Rob, you can call me anything it's Friday :rofl:, in answer to your question they we're trying to fix the floor in my van apparently they drilled holes underneath and insert the needles in put the resin in, but as I said they broke 3 , so it goes back in October and pilote will fix it šŸ¤žšŸ¤ž
Shame the floor quality in these relatively new vans are poor.
I'm trying to put off fixing with resin but fear that it's the only way to go.
The underneath of the floor is protected with a pvc sheet, does that mean the Dealership would have drilled through yours to get the resin in?
Rob
 
Jan 9, 2014
111
125
Scotland
Funster No
29,628
MH
Rapido 803F
Exp
Since 2006
I looked into this years ago to fix a partially delaminated floor on an old MH.
I remember reading at the time that, if using epoxy resin, then it was very important while the resin was curing, to also remember to temporarily shore up the underside of the floor, in conjunction with putting weights on the top as described in various posts above. This was to prevent any expansion from bulging the underside of the floor.

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TheBig1

LIFE MEMBER
Nov 27, 2011
17,160
40,923
Dorset
Funster No
19,048
MH
A class
Exp
many many years! since I was a kid
I looked into this years ago to fix a partially delaminated floor on an old MH.
I remember reading at the time that, if using epoxy resin, then it was very important while the resin was curing, to also remember to temporarily shore up the underside of the floor, in conjunction with putting weights on the top as described in various posts above. This was to prevent any expansion from bulging the underside of the floor.
many years ago it was more of an issue with lightweight 3mm ply on the underside. Manufacturers now use coated or better quality ply. Unless the floor is damp or split I would not worry about propping up the underside. Everything gets done from above to maintain structural strength and water tightness. Once the resin sets it is stronger and more durable than the OEM composite that relies on the heat and pressure bonded glue between ply and urethane foam. One downside is that it does compromise an area of thermal insulation on the floor. However the trade of on cost and disruption to the owner makes this very cost effective. It is all that a dealership will do under warranty anyway
 
Oct 25, 2018
14
10
Funster No
56,919
MH
Pilote P740FC
Exp
14 years
The floor in our Pilote is 50mm which comprises of 45mm foam sandwiched between 2.5mm ply
This construction is obviously the reason for the premature delamination.
 
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OP
neilydun
Apr 18, 2013
118
173
Nuthampstead
Funster No
25,596
MH
Rv
Exp
since 2013
The floor in our Pilote is 50mm which comprises of 45mm foam sandwiched between 2.5mm ply
This construction is obviously the reason for the premature delamination.
I didn`t even know 2.5mm ply was available. I thought 4mm was the thinnest

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POH

May 29, 2018
1,107
803
Funster No
54,135
Shame the floor quality in these relatively new vans are poor.
I'm trying to put off fixing with resin but fear that it's the only way to go.
The underneath of the floor is protected with a pvc sheet, does that mean the Dealership would have drilled through yours to get the resin in?
Rob
Hi Rob, yes they were going to do the resin thing and then seal it with some sort of dowelling and then with some underseal stuff .
 
Jan 17, 2021
33
91
Essex, UK
Funster No
78,836
MH
Phoenix 8800
Exp
Since 2004
Our van has a honeycombe floor of some kind of synthetic material about 50mm thick. I understand it's the same sort of material used for aircraft flooring. Very light in weight but very stiff and strong and no chance of rotting. I scrounged a few pieces from Phoenix which make excellent pads under the hydraulic jacks. Do any other makers use such synthetic materials?

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Sep 2, 2014
517
670
Near Colchester, Essex
Funster No
33,147
MH
Burstner Nexxo
Exp
12 years
Thanks for the replies.
Its a Gulfstream Sun Voyager.
Has anyone tried the single part adhesives ?
I presume its an expanding PU adhesive like Gorilla glue.
Just to check, with this type of repair, drill through the top sheet of ply only, then inject, dowel and weight down ?
Do not use a foam type Gorilla glue, you need to use a two part epoxy resin, you an easily inject it into the ply through the prepared holes.
We used to use this method on ply boat decks with great success.
The Gorilla foaming type of glue will probably push out the dowels if you use them, we never used foaming glue on decks as the resin was stronger than dowels, so we filled up every hole with resin.
The dowels have a grain in them which over time may let in water and rot away.
I hope this helps.
 
Sep 23, 2019
24
20
Funster No
64,680
MH
C Class
Exp
3 months
Cutting out and a full repair is a much larger job than you might expect. A delamination kit, injecting resin is by far the least destructive method. One thing that some neglect to do is add a sheet of polythene over the area before adding weight to any bulging area. This prevents any seepage from gluing the weights (bricks are ideal) to the floor
I agree wit using a delaminatin kit. I was advised not to use the one-part resin as it expands so I used a 2 part resin kit. It's ot difficult to do- just a bit messy.
 

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