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Under Floor Timber Protection.
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user23addy46
Posted: 18 December 2018 9:03 PM
Subject: Under Floor Timber Protection.
 
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Location: Central Deserts of Lancashire !


Hello fellow Motor Homer's -
Following a complete failure in searching for a 'similar / same layout' replacement of our 2009 reg. Bessacarr E695 (we still prefer end lounge + 'over cab storage' 20 yrs. on !) - and after its recent 'Habitation Check' @ Todds Leisure (Preston) report "no problems, its perfect" - I would be foolish not to offer some form of protection to the ply underfloor (a 1998 Royal Ensign 610 SE we owned suffered a floor rot problem) - I now need to consider the best way forward in offering some weather protection to the under-floor Plywood of 'Bessie' (some form of matt black painted from new) ?
Whilst there are proven metal protection products (eg:- Waxoil) I cannot recollect any plywood products, or have i just had my head in the sand ?

Anyone out there used or seen results of a successful under floor plywood protection please ?..

Many thanks



userGman
Posted: 18 December 2018 9:17 PM
Subject: RE: Under Floor Timber Protection.
 
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Posts: 16

Location: Kippax, West Yorkshire. CI carioca 694


Don't usually reply on here, but I've just done our M/H
used Hammerite spray on, it's a messy job but worth it
I think, don't forget to do where the sides meet the floor.

https://www.ebay.co.uk/itm/Hammerite-Black-Original-Car-Van-UnderBody-Arch-Under-Seal-Waxoyl-Spray-600ml/290350917690?epid=1023548983&hash=item439a43683a:g:rPoAAOSwyZ5UmUYn:rk:16:pf:0

steve.
userDerek Uzzell
Posted: 19 December 2018 7:05 AM
Subject: RE: Under Floor Timber Protection.
 


5000500050001000500100
Location: Herefordshire - 2015 Rapido 640F LHD 2.3ltr 150bhp


David

There are products marketed for waterproofing plywood

https://tinyurl.com/ybnuqtfr

and preserving the plywood floor of motorhomes has been discussed here in the past

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Hints-and-Tips/Sealing-under-floor-woodwork/36067/

and on-line generally

https://tinyurl.com/y7zcd528

Spraying the underside of a motorhome with its wheels on the ground will be an unpleasant job, make more difficult if it’s attempted outside and in cold weather. Years ago, when I owned a Herald motorhome with a plywood floor that had an unprotected lower surface, I Waxoyled the vehicle’s underside and had to ‘cook’ the stuff to make it thin it enough to spray successfully. It’s not a task I’d ever want to do again and, fortunately, the floor of the Hobby motorhome that followed the Herald and the floor of my current Rapido both have an underside protected by a GRP skin.

You might try contacting these people

https://www.waxoyltreatment.co.uk/?gclid=EAIaIQobChMIhs2D-q2r3wIVQZztCh0MzwwCEAAYASAAEgJcafD_BwE

and ask them about treating a motorhome’s plywood floor.
userBrian Kirby
Posted: 20 December 2018 4:13 PM
Subject: RE: Under Floor Timber Protection.
 


500050005000100010010010025
Location: East Sussex. Motorhome: Knaus Boxstar 600 Street


I would suggest that you look at Waxoyl, which you can get from Halfords along with a high pressure spray lance. It has the great advantage over most other rust protection treatments that it remains flexible, and is highly penetrative. It will need to be re-applied occasionally, but being a diluted wax that sets to the (approximate! ) consistency of cart grease within about 24 hours (depending on temperature) it will to some extent self-repair if scratched, but will eventually be abraded by road grit etc over time.

It is a filthy job, as Derek says, and would best be carried out during warm weather and, if doing it on your drive, you will need to cover the drive with something to catch the spray drift and inevitable drips, or the drive will become greasy, smelly (it pongs until it has set) and unsightly.

The only caveat I have (apart from the mess!) is whether it would react in any way with the glues in the plywood. I'm assuming that they will have a technical advisory department that could advise on this.
userjumpstart
Posted: 20 December 2018 4:20 PM
Subject: RE: Under Floor Timber Protection.
 
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Posts: 163
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Location: Somerset


Spray /coat with SBR . Used by tilers to waterproof ply before tiling.Get from Toolstation/Screwfix etc.
usermonique.hubrechts@gm
Posted: 20 December 2018 5:16 PM
Subject: RE: Under Floor Timber Protection.
 


Epic contributor

Posts: 1335
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Location: essen belgium


Is that the same as DINITROL as I used on my datsun 1200 coupe. Was and still is perfect for hidden places on metal plate. But on wood?
userhallii
Posted: 20 December 2018 5:24 PM
Subject: RE: Under Floor Timber Protection.
 


Epic contributor

Posts: 1541
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Location: Worcestershire Hymer Van 522 2007


Dinatrol is different to Waxoyl being more fluid and not waxy like Waxoyl. I have only used waxoyl on my ply under floor and it has worked well. Messy but worth it, do the chassis as well including the box sections, twice as messy. Baby oil gets the stuff off your hands, face, arms, neck, hair and everywhere else!


H
userBrian Kirby
Posted: 20 December 2018 6:41 PM
Subject: RE: Under Floor Timber Protection.
 


500050005000100010010010025
Location: East Sussex. Motorhome: Knaus Boxstar 600 Street


jumpstart - 2018-12-20 4:20 PM

Spray /coat with SBR . Used by tilers to waterproof ply before tiling.Get from Toolstation/Screwfix etc.

Personally, I wouldn't use SBR (styrene-butadiene rubber) as a first preference. This forms a waterproof skin but, on the underside of a van as opposed to being snug on a ply sarking beneath tiles, it will be exposed to everything the road can throw at it. If it then gets damaged the wet will spread unseen behind the SBR, which is exactly what, IMO, one is trying to avoid. In practise, it will merely be the equivalent of traditional underseal, and is likely to develop the same problems.

Waxoyl, OTOH, (or similar products) to not skin, but merely set to a thick, waxy, coating that creeps into all manner of nooks and crannies. It isn't one-shot, but it offers much better protection if damaged as, the substrate is left waxy an so water resistant, plus it tends to self-repair - albeit within limits. As above, my caveat is whether it might react with the glue in the ply, possibly causing de-bonding. The glue should be waterproof (WBP grade - ideally marine, but I can't see many manufacturers paying the extra for that!), but I don't know whether it would also resist the oily constituents of Waxoyl.
userBrian Kirby
Posted: 20 December 2018 6:44 PM
Subject: RE: Under Floor Timber Protection.
 


500050005000100010010010025
Location: East Sussex. Motorhome: Knaus Boxstar 600 Street


hallii - 2018-12-20 5:24 PM...…….. Baby oil gets the stuff off your hands, face, arms, neck, hair and everywhere else! H

This creates an intriguing image of your state of dress when applying the Waxoyl!
userDerek Uzzell
Posted: 21 December 2018 7:54 AM
Subject: RE: Under Floor Timber Protection.
 


5000500050001000500100
Location: Herefordshire - 2015 Rapido 640F LHD 2.3ltr 150bhp


I notice that questions have been asked in the past about potentially negative effecs of treating the underside of a motorhome’s plywood floor with various materials, and - where a hard-and-fast opinion has been given - it has been that Waxoyl should not penetrate far enough into the plywood to harm the glue. This view is based on the plywood being ‘marine grade’, which is a reasonable assumption but not necessarily always the case.

https://tinyurl.com/ydhoprov

Other treatments suggested were Dinitrol or Dynax UB

https://www.dinitroldirect.com/product-category/dinitrol/

https://www.bilthamber.com/corrosion-protection-and-rust-treatments/dynax-ub
userMuswell
Posted: 21 December 2018 9:35 AM
Subject: RE: Under Floor Timber Protection.
 
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Location: North London


Marine ply uses waterproof glue but the wood is untreated so it will still rot if it is unprotected.
usercoppo
Posted: 22 December 2018 6:08 AM
Subject: RE: Under Floor Timber Protection.
 
Just joined

Posts: 10

Location: Concorde Concerto 2005


Difficult one this, it's like saying what should I treat a pathetic, useless, cheap material with.

Plywood should never have been put on underfloors, Hyme r certainly now know this, the amount of Hyme r floors I have put my fingers straight through is amazing.

If new timber I would just use Tung oil or something, checked and a quick recoat yearly.
userDerek Uzzell
Posted: 22 December 2018 8:41 AM
Subject: RE: Under Floor Timber Protection.
 


5000500050001000500100
Location: Herefordshire - 2015 Rapido 640F LHD 2.3ltr 150bhp


When a motorhome is fitted with a plywood floor that has an unprotected under-surface, that floor should not be expected to last forever. But the historical method of constructing coachbuilt motorhomes has been to use a plywood floor (either solid plywood or with plywood ‘sandwiching’ an insulation core) and it would be interesting to know which (if any) manufacturers of (say) pre-2010 coachbuilt models were NOT employing a plywood floor and, of those manufacturers using a plywood floor, how many manufacturers were protecting the floor’s underside with other than a lick of paint or a layer of ‘car type’ underseal.

It’s only relatively recently that motorhome construction methodology has begun to move away from using wood in bodywork and, even though the floors of coachbuilt motorhomes now tend to be better protected, floors that have a GRP-sheathed underside will still have plywood beneath the sheathing. Plywood is used for motorhome floors because it’s available in large flat sheets, it’s strong and light, accepts fixings well and, provided that it is the correct plywood type and protected from water penetration, should last the realistic life of the motorhome.

David does not suggest in his original posting that the plywood floor of his 9-year-old Bessacarr has rot in it - he just wants to try to ensure that it stays rot-free.... Tung oil would be unsuitable for doing this, for (as you say) it needs to be used on clean bare wood, not on wood that has any other type of finish (paint, underseal, etc.) and it’s 99.9% certain that no motorhome manufacturer will have used a plywood floor that has no finish whatsoever on its under-surface.

As long as a coachbuilt motorhome’s plywood floor is in good condition, spraying its underside with Waxoyl (or a similar product) should not cause harm and should provide useful protection against water penetrating the floor from beneath the vehicle. What it won’t do is cure existing rot, nor provide protection from water penetration through the floor’s top surface as (apparently) happened with the Auto-Sleepers motorhome mentioned in this earlier discussion.

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Rotten-wood-underneath-MH/40901/
usercoppo
Posted: 22 December 2018 11:04 AM
Subject: RE: Under Floor Timber Protection.
 
Just joined

Posts: 10

Location: Concorde Concerto 2005


Derek, I have to disagree somewhat

Plywood floors on the underside of any Motor home is bad, simply because of the fact that 99% of owners never even look underneath, out of sight out of mind so to speak. It's ok for dedicated people like yourself and me who check and look after them but it is meant to be checked annually and treated, then any areas made good. Most people don't even look underneath, then it's gets sold through different hands and becomes a damp soggy mess. I always think how will that van fare in 10 years and on the 3rd or 4th owner etc.

I have looked at many Hymers from 1997 onwards which have been a soggy mess underneath, putting my fingers straight through, owners oblivious, when contacting them initially it's the first question asked and the comment is horror, what a cheek, mine is perfect, in fact when you get there they didn't even know the floor is plywood. Often the only time they realise is when it has come through the garage floor.

Then look at a Niesmann or concord e of the same era, floor perfect underneath. Because it's GRP or aluminium as in our little concorde. No wood used at all even beneath the GRP or ally, result, last forever.

It's a cheap nasty material is plywood for a exterior floor and the price of motorhomes should be reflected in the materials, but never is.

This is the construction of our 2005 little van, as you see no wood underfloor although you are correct some manufacturers did/do use plywood still and I cant see any justification for it in this day and age. Recipe for disaster due to the reasons given.

At last Hymer have finally seen the light and ditched plywood, about 20 years too late though.




Edited by coppo 2018-12-22 11:31 AM




(Concerto 2005 construction.jpg)



Attachments
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Attachments Concerto 2005 construction.jpg (78KB - 32 downloads)
user23addy46
Posted: 16 February 2019 9:41 PM
Subject: RE: Under Floor Timber Protection.
 
Just joined

Posts: 10

Location: Central Deserts of Lancashire !


Hi - further to my December 18th 2018 "Under Floor Timber Protection" enquiry - having (yesterday and today) enjoyed the high temperatures (15 c) here in the central deserts, i managed to complete the task of weather proofing the plywood underfloor of 'Bessie' - Following long, detailed discussions with many 'wood preservative' suppliers, I finally settled upon Cuprinol Wood Preserver Clear (BP) - ie:- a solvent based preserver (with very little smell ?) , BUT prior to treating the Motorhome under floor area, I applied a few test areas of my (30 yr old) Garden Shed by applying the above preserver along side the 'standard' water based shed preserver to assess the performance of the new Cuprinol Clear (BP) - One reason being to test the application of the 'New' preserver by my rather old 'Wagner W300' electric spray gun ! This proved to me both (A) the viability of being able to (low pressure) spray the Cuprinol Clear, and (B) that it does soak in very well indeed. Allowing an hour between the first coat I then re-sprayed a second coat, again being absorbed very well indeed. The overnight rain (yes we do get the occasional rain here !) showed both the treated test areas to be water repellent, the difference being THE CUPRINOL CLEAR WAS SPRAYED ON - THE WATER BASED WAS BRUSHED !!! So the ability to spray the Cuprinol Clear (BP) was the 'Clear winner' (Pun) - it took no more than simply backing up onto the ramps to provide easy access, with the first coat (a full litre) was completed within an hour (Note:- I have a 'bendy' flex nozzle for the gun so was easy to hold the gun level whilst 'spraying up' onto the floor), the Cuprinol soaking in to the ply very quickly - I applied a second coat today, again it soaked in to the ply well, giving me no cause not to believe it will provide good water proofing qualities - AND, as it was so easy to complete, I shall re apply the preserver on an annual basis ! - Total time 2 hours approx - total cost for 2.1/2 litres Cuprinol Clear (BP) , less than £28.00 delivered via E Bay.
I am now, far more confident with the under floor area !
Hope this is of some help, the important point being "My plywood under floor is sound, no rot" - as has been pointed out so many times - this would not / can not help if rot is present !

Thanks to all who contributed.
Dave Adams
.

userEJB
Posted: 17 February 2019 12:48 PM
Subject: RE: Under Floor Timber Protection.
 
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Posts: 390
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Location: Suffolk Burstner Nexxo T620G


If a plywood floor is sealed underneath it may not dry out if it gets wet.
Most modern protected floors (Fibre glass or alloy sheeting) are also sealed on top to stop the ingress of water.
Many 20 to 60 year old caravans have perfectly sound bare ply floors.
Appreciate they don't often do too much distance.
userbolero boy
Posted: 17 February 2019 6:15 PM
Subject: RE: Under Floor Timber Protection.
 


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Location: Somerset 2017 Carthago C-Compactline i138


can't add anything to the above treatment comments except today that it was also aart ocular text of Swift vans of that era (we had one...) to be shy of decent rear mud flaps and exposed floor edges...
it might be worthwhile to look at these issues as well....to aid prevention of unnecessary water 'attack'.
userpelmetman
Posted: 17 February 2019 9:30 PM
Subject: RE: Under Floor Timber Protection.
 


Walks with the gods

Posts: 25315
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Location: 1990 Ford Travelhome.Currently of no fixed abode..


EJB - 2019-02-17 12:48 PM

If a plywood floor is sealed underneath it may not dry out if it gets wet.
Most modern protected floors (Fibre glass or alloy sheeting) are also sealed on top to stop the ingress of water.
Many 20 to 60 year old caravans have perfectly sound bare ply floors.
Appreciate they don't often do too much distance.


The plywood floor in our 29 year old camper has only suffered damage from the step because the bolts were counter sunk a 1" into the 2" ply ..........and a leak from the water filler which I didn't detect for a couple of years .......

That said they were both sorted by myself at minimal cost .......

and a damn sight cheaper than repairing the rust in my works van .......

Edited by pelmetman 2019-02-17 9:36 PM
userWill86
Posted: 18 February 2019 11:11 AM
Subject: RE: Under Floor Timber Protection.
 


1000500100252525
Location: Gatwick. Rapido 987 M. Now a VW Nexa


"WORKS VAN?"
userpelmetman
Posted: 18 February 2019 12:41 PM
Subject: RE: Under Floor Timber Protection.
 


Walks with the gods

Posts: 25315
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Location: 1990 Ford Travelhome.Currently of no fixed abode..


Will86 - 2019-02-18 11:11 AM

"WORKS VAN?"


A 1999 Mk 5 Transit Will.......commonly known as Fanny the Tranny .....

user23addy46
Posted: 26 February 2019 3:36 PM
Subject: RE: Under Floor Timber Protection.
 
Just joined

Posts: 10

Location: Central Deserts of Lancashire !


Hy and thanks for your reply, however in addition to your comments, many "Old Caravans" etc. did not have the complex pressurised water systems on board (our first caravan new in 1967) still had Gas Lighting plus a 'Foot Pump to get the water from the outside 'bucket' to the sink !) therefore could not have water leakage of the type now sometimes experienced - Further, whilst I cannot claim to have the knowledge or experience to check - I have very grave doubts that any manufacturer past (or indeed present) would have the ability (or more realistic) the desire to provide an effective 'water proof seal' twixt the inside floor to side walls or skirts of any motorhome or caravan ? The point I made was to offer what (after lots of research) I fully believe to be a very efficient & with a spray gun, relatively easy way to extend the working life of any exposed (but sound) 'underfloor area' in preventing water rotting ingression to the same. In the interest of painting a background to the above, I should point out the following :- Following collection of our brand new 'Bessie', August 2009 from 'Discover Chorley, Lancs' (ex Barrons), I made the
alarming 'discovery' of eighteen (18 No.) easy identifiable faults, varying from a simple blown fuse on the toilet flush to far more concerning problems such as completely inadequate applications (to a measured 1.5 Mtrs.) completely missing black PU sealant. This area spread between the underfloor to Cab, PVC wheel arches, the side and rear skirts ! Further 'stupid' errors such as the 6cm miss-alignment of the mudflaps, fractured outlet elbows to both fresh & grey water tanks along with two 2 (No.) blue water pipe couplings that hadn't been fitted correctly all showed up when the water tank(s) where first filled ? Thus begging the question - WHAT Pre Delivery Inspection took place ?.- To shorten what could be a very, very long report - As the Discover Group were in very serious financial debts at the time (a friendly bank 'insiders' knowledge proved to be accurate !), plus they where only 'able to look at my issues in ' 2 or 3 weeks time', And not wanting 'Bessie' to be entrapped within any "Financial Receivers" issues, I took it upon myself to successfully put to right and modify the many issues, such as application of three (3 No.) tubes of black PU sealant to the main (underfloor) problem areas along with repairs and sensible modifications to the many others items, including the application of Truck Standard flexible 'Brush' mudflaps that DO what the original fitments couldn't possibly achieve. To this degree I have been very involved with all areas including the under floor areas of 'Bessie' since my purchase - so I am able to comment with accuracy re all the above...

Take care and lets hope the problem of Brexit problem sorts its self out soon -

Dave Adams

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