Water stains on wooden interior walls

[Floating Guye]

Hi there,

 

I had a small inside flood on my boat last year (when a mate left a tap on in a blocked sink - circa 100L overflowed according to our guesstimates) and although I cleared out almost all of the water that had seeped down into the hull with a wet vac over the following 2 days, there remain cosmetic (?) signs of damage to some of my wooden walls and also to some floorboards (though less visible).

 

The remaining (visible) damage amounts to:

 

-staining at the base of a couple of wooden partition walls

and

-rippling in the oak veneer floorboards.

 

Could you please let me know if:

a) any of this is a problem structurally (i.e. will the wood start rotting, or something similar?)

or

b) if anything can be done to either fix it (short of pulling the wood panels out & replacing them) or at least cover up the visual signs of the past flood. One suggestion that was given was to attach skirting boards at the base of these walls, so as to cover the stains. But I was wondering if there might be some kind of substance to "paint" over the top of the markings... but I imagine that any such substance might be likely to add a colour... like there wouldn't be a "transparent" version of this that could somehow magic away stains, I imagine.

Anyway, I have attached a couple of photos to give you an idea of the damage (the rippling in the floorboards is less obvious). Please let me know your thoughts!

Thank you!

Chris

[blackrose]

If it was all dried out within a reasonable time period and has remained dry since then generally no rot or structural problems would result. Wood rots when it's soaked and stays wet or is repeatedly soaked. Did you definitely get all the water out of the bilges?

 

I can't really help with the cosmetic repairs but someone with more knowledge will be along soon.

 

I bet you were happy with your mate. That's why I wouldn't let anyone use my boat while I'm away. I did it once and the idiot blocked the toilet and left the bathroom light on for two weeks which ran the batteries flat. Nobody cares for your boat like you do.

Edited January 31, 2022 by blackrose

[Floating Guye]

Totally - can definitely relate to that feeling of no one looking after your boat like yourself! Amen to that.

 

Yeh, I've kept sticking my hand down into the hull cavity ever since and it's dry as a bone down there. From the sound of it, I may well have avoided wood rot then 👍

The only slightly tricky bit is with the floorboards - so the oak veneer panels themselves are highly waterproof - standing water would have to sit on top of it for days for it to seep through, and even then it would only be at the joins, if at all. The issue, however, was that the during the flood the water flowed to the sides, where the walls join to the floor panels, and there are cracks here where water can get in (hence the 100L getting into the hull). When the water filtered into these cracks, it will have been partially soaked up by the composite wood that underlies the oak veneer on the surface (some kind of good quality MDF, I'm told). The issue with this under-layer is that it is much more absorbent, and since the capping layer of oak veneer is so watertight, it is also unbreathable. The result of all of this, I have concluded, is that having seeped in, the water would have been sucked up by these MDF layers and then may have difficulty drying out, since it cannot "breathe". I say this because the rippled floorboards used to be everywhere, but over the months the ripples nearest radiators or the fireplace have flattened out and disappeared - this makes me think that, if I could get enough heat to these areas, I could perhaps still "drive out" the remaining moisture...

Any further thoughts welcomed. Thanks Black Rose

Edited January 31, 2022 by Floating Guye

[Bee]

Bleach of some sort might work. Oxalic acid is the one that I would try but apart from that I can't help.

[Tracy D'arth]

Paint a base line skirting to cover the stains. You will not reduce them by any treatment, the glue/resin in the composite will resist bleaching.

A good reason why MDF or chipboard should never be used in a boat I am afraid.

[blackrose]

Unless it's waterproof MDF. My tiled bathroom counter is made from green waterproof MDF. I left a large offcut outside on the pontoon for about 6 months in the rain and it was still fine when my neighbour asked if he could use it to build a cupboard. It had gone a bit yellow from the sun but it was still flat and hadn't absorbed any water. People talk about MDF as if it's all the same stuff but there are different grades and some are fine for boat use 

[ditchcrawler]

8 minutes ago, blackrose said:

Unless it's waterproof MDF. My tiled bathroom counter is made from green waterproof MDF. I left a large offcut outside on the pontoon for about 6 months in the rain and it was still fine when my neighbour asked if he could use it to build a cupboard. It had gone a bit yellow from the sun but it was still flat and hadn't absorbed any water. People talk about MDF as if it's all the same stuff but there are different grades and some are fine for boat use 

No one will believe you. my ceiling is MDF and I have bits kicking around 20 years later still in one piece

[Mike Jordan]

You can find out how to use Oxalic acid solutions by looking at. -constructionchemicals.co.uk

You can normally buy a small quantity from the local chemists shop.

It’s sensible to try a small area first.

best of luck

Mike.

[GUMPY]

I would be tempted to  fit a skirting board along where its stained, it will cover the marks and you could stain it to match

 

[RichM]

Oxalic acid works in some scenarios on natural wood.
 

I had this problem on my boat, albeit much worse. Photo can be seen here. It really annoyed me as I hated defects/imperfections like this. Oxalic acid worked wonders on my oak kitchen worktop before re-coating in Danish oil but it failed to do anything on plywood/cabin sides et al. In fact, if anything it made it worse by removing the grain effect but that was perhaps my fault for being too aggressive.
 

Really love the natural wood look but once water damage sets in, it's very difficult to remove the damage and if you're not careful you can easily make it worse. I guess this is why many resort to the good ole' paintbrush but of course once you do that, there's no going back!

 

On the subject of paintbrushes, I have seen a solution whereby you can paint on a wood effect, but you have to replicate the grain effect. I did not try it as I wasn't confident I'd be able to replicate the natural look. This video gives some idea how it can be done though.
 

 

For what it's worth though, I don't think the floor is too bad and unless you pointed it out I wouldn't have noticed. If anything it gives it a more rustic look. The water damage at the base of the cabin partitions can be masked as suggested but the key thing is prevention. Obviously you don't want it to get worse. There's several different products (e.g. Danish oil) which you can apply to prevent water ingress but bear in mind that these may change the natural look/appearance and need to be re-applied periodically.  
 

Good luck!

[Floating Guye]

So it turns out the underlying wood in the sub-flooring is not in fact MDF but "Eastern plywood", according to my manual. I don't know if this changes anything - would plywood be more water-resistant (or better at drying once wet) than MDF?

On 01/02/2022 at 18:06, RichM said:

Oxalic acid works in some scenarios on natural wood.
 

I had this problem on my boat, albeit much worse. Photo can be seen here. It really annoyed me as I hated defects/imperfections like this. Oxalic acid worked wonders on my oak kitchen worktop before re-coating in Danish oil but it failed to do anything on plywood/cabin sides et al. In fact, if anything it made it worse by removing the grain effect but that was perhaps my fault for being too aggressive.
 

Really love the natural wood look but once water damage sets in, it's very difficult to remove the damage and if you're not careful you can easily make it worse. I guess this is why many resort to the good ole' paintbrush but of course once you do that, there's no going back!

 

On the subject of paintbrushes, I have seen a solution whereby you can paint on a wood effect, but you have to replicate the grain effect. I did not try it as I wasn't confident I'd be able to replicate the natural look. This video gives some idea how it can be done though.
 

 

For what it's worth though, I don't think the floor is too bad and unless you pointed it out I wouldn't have noticed. If anything it gives it a more rustic look. The water damage at the base of the cabin partitions can be masked as suggested but the key thing is prevention. Obviously you don't want it to get worse. There's several different products (e.g. Danish oil) which you can apply to prevent water ingress but bear in mind that these may change the natural look/appearance and need to be re-applied periodically.  
 

Good luck!

And thanks Rich - this is really helpful and quite reassuring about the rippled floorboards. What I would say, however, is that although the casual observer would never notice them (they are very subtle, as you say) I worry that were I to carry out a survey some day, a surveyor would very likely pick it up. 

 

Thoughts on this? I don't know quite how thorough surveyors are, and I've even heard that they can be quite blasé and gloss over a lot of things.

 

Thanks again for your help!

[Mike Jordan]

Far Eastern plywood varies greatly in quality and is the cheapest available. It’s reaction to water varies from a little temporary swelling through to turning it into something that resembles puff pastry! As for surveyors, their opinions and level of honesty vary  depending on who is paying them and whether they are qualified in any way. For instance if you are buying a boat from a broker, only a fool would use the surveyor they recommend to examine the boat.

NB there are good honest surveyors out there but you need to be cautious.

[David Schweizer]

I have never found any treatment that will get rid of water stains in timber, without also altering the base colour of the wood. I would go along with the suggestion of adding a narrow skirting board to hide the marks, You may be able to find something suitable in oak in a timber merchant or DIY outlet with a decent mouldings stock.

 

Edited to add :- Wickes advertise a range of Oak veneered skirting board, but it isn't cheap!

 

 

Edited February 3, 2022 by David Schweizer

[David Mack]

If you are within reach of Skipton, https://www.britishhardwoods.co.uk can supply more or less anything you want in oak. And if you want something not on their standard list they are very accommodating if you give them a call.