Rotten floor?

Phantom

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There was perhaps a bit of a single slightly softer spot on the motorhome floor when we bought it over 3 years ago but was of no great thought. Though after fulltiming in it for the last year the most heaviest trafficked floor areas have become noticeably more flexible, a total area of about 1sqm, so will need to fix that soon when we are not living in it but haven't checked the floor out too much yet apart from getting under the MH and finding the plywood floor base to be completely sound.
I'm not sure of the floor construction in that forward problem area, but further back where there is access to the grey waste tank the floor is a solid 39mm thick, made up of vinyl, 6mm ply, 30mm solid timber, and 2mm ply. But that tank is boxed and insulated so guess that the floor elsewhere could be of a different construction, or not? Yep, I know I need to check it out for sure.
I was quite surprised to see only a 6mm ply top layer back there but if so all over that would actually account for the flex if only an insulation board breakdown or even a rotten timber board below it?
The motorhome is pretty much a 2005 Hymer and I would have assumed the floor to be constructed of ply/insulation/ply sandwich, but I'll check it out properly in a few weeks time and maybe just a resin injection will cure it? It's still no great deal even if I have to cut out and replace that part of the floor as it's only really between the bench seats. But would appreciate any thoughts in the meantime. 👍
 

yorkshireCPLE

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Just done ours a month or so back using https://www.ebay.co.uk/itm/19180211...%2Fy7Fm%2F6xvQ%3D%3D|ampid:PL_CLK|clp:2334524

Worked a treat.. Had to go and buy some more dowel though as the kit comes with about 30 I think, I used about 65 as it was a large area from main hab door and all the kitchen area. 1 Bottle and used all of it just about. I think there was about an inch left inside. Started in the morning and was able to go in at night to bed. It's a quick fix, just hope it's long lasting..
 

Snapster

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I’ll agree that it sounds like delamination especially in high traffic areas. We had similar in our old RV, the soft areas were in front of the kitchen sink/ cooker, and between the bathroom and shower, leading into the bedroom. Resin injection cured it.
Just to rule out any damp, are you able to check the spongy area with a damp meter?
 

QFour

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The flexing breaks down the glue so flexing has to be due to lack of support but supports add weight so there has to be a balance somewhere. If it is wet the interior core seems to turns to wood dust. I put a piece of decent ply in a tub of water and left it outside in February. Checked it a couple of weeks ago and ply is still solid. Only conclusion so far is that MH manufactures must use the cheapest ply they can get. Lots of different types and some actually use waterproof glue. Pity they don't use epoxy resin but it would add weight.
 

Pudsey Bear

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That warning label is a bit omnibus, and I have had experience with Dichcloromethane, (it will remove powder coating from bike frames) it strips skin with prolonged use. the rest will just kill you eventually, no mention of mask type required or what it's like once cured.
 

Snapster

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If you work with it long term, ie heated vats for furniture stripping, you should wear protective clothing including full face masks. But, injecting it into the floor from a bottle would present little risk as long as the area is ventilated and you wear latex or similar gloves. Once dry, there will be no fumes or vapour coming off and the holes in the floor will be plugged anyway.
 

Pudsey Bear

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Yup, I'll go along with that, then you have to cover the area with something that will withstand movement, in ours I'd probably go with laminate, rather than vinyl, but the doors are too low then you get into cutting bits off the bottom, yuk.
 

Snapster

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Sounds like a major refit! We were lucky with ours, it had a vinyl floor that I took up then replaced after it was all dry.
 

yorkshireCPLE

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That warning label is a bit omnibus, and I have had experience with Dichcloromethane, (it will remove powder coating from bike frames) it strips skin with prolonged use. the rest will just kill you eventually, no mention of mask type required or what it's like once cured.
There was very little to no fumes but we had all windows wide and sky light open full. We used the syringe and found that to be easiest and cleanest method but each to their own. We laid some really cheap lino stuff down before we went to bed. The hardest bit was preping the floor ready to lay lino as some bits had expanded past the dowls. So just got a sander on the go and sorted that out..
 

jacquigem

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Anyone done it twice ? I repaired ours maybe 4 years ago , worked really well . Have lived in it for half that time and now getting a few "squeaks" from the most used areas. Still no sign of damp so thinking shoving some more resin down ?
 

Phantom

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We were lucky with ours, it had a vinyl floor that I took up then replaced after it was all dry.
On ours the vinyl looks to be well bonded and goes under bench seats either side of the problem area so am happy to just drill it as the carpet will cover it all.
 

Phantom

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I guess that the best practice is to set a drill depth stop at the lower ply board so that the resin gets both above and below the insulation to fill any gaps, I am thinking of 10cm hole spacings. That is of course assuming that my floor is of such a construction?
 

Snapster

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Anyone done it twice ? I repaired ours maybe 4 years ago , worked really well . Have lived in it for half that time and now getting a few "squeaks" from the most used areas. Still no sign of damp so thinking shoving some more resin down ?
You may have different areas of ply that are delaminating. Give it a go, it can’t do any harm.
 

yorkshireCPLE

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I guess that the best practice is to set a drill depth stop at the lower ply board so that the resin gets both above and below the insulation to fill any gaps, I am thinking of 10cm hole spacings. That is of course assuming that my floor is of such a construction?
Be careful that it doesn't expand and push the bottom out. I would stick some tape on the drill bit at the depth of dowl only. That way the resin will run into the areas needed then expand only in the gaps. Someone on YouTube drilled to the bottom and caused more trouble than it should of been. But each to their own..
 
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