Dry rot problem - Advice?

stuhaynes

stuhaynes

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We're coming out of the water in 4-6 weeks for routine antifoul etc. We are also going to install a 55 litre calorifier across the bow (we need the ballast anyway). Currently the whole of the bow is a big double bed that stands about 650mm above the deck. Originally this was 2 berths, one each side, below which are mahogany facias with drawer fronts, but no drawers. These facias effectively cut off the hull (below the bed) from everyday inspection. It also means that there is no ventilation to speak of, ideal breeding ground for dry rot I believe.
Today I took out the bed and removed a drawer front to see what size calorifier I could fit. I saw patches of a white cotton wool like substance here and there where the torch would reach. I believe that this is dry rot.

The boat is 60 years old, mahogany on oak.

I need some advice:confused: How do I get rid of the mould? I could jet wash it off, but I've got 2 problems with this. The first is that the jet wash may knock out the white lead caulking and secondly, if the mould is not dead I may be spreading the problem into the bilges.

I've read that Boron based products are good at treating this problem, but have no experience of it. Anyone used Boron and if so, what further protection was added? I thought maybe proper red lead paint, Lead being poisonous to most things might work, but don't know. Any thoughts anyone?

I should add that the current non ventilated situation is being ended. I'm going to remove the mahogany facias, to allow the required ventilation, and fit a pair of low wattage heaters, one each side. Currently we use a single 500 watt heater in winter, so 2 x 250 watts below the bed should warm both us and the hull. Any lost heat from the calorifier will also warm the space.

As I see it I have to kill the mould somehow and then jet wash it into the bilge where the pump will remove it from the boat. Should I do this before we come out of the water, or while we are on hardstanding?

I need a plan of attack if anyone can help.
Thanks.
 
If it has got to the stage of white fruiting bodies with Dry rot its likely to be rampant. Once you have opened the area up you need to see how rotten the timbers are & cut them out & replace, it will be pointless to do anything else. Borate based wood preservers work as do cuprinol but will not make rotten wood good again.
Forget proprietary snake oil like Git rot or epoxy they wont stop it either.
If its really bad a gallon of diesel & a match kills the rot quite well.
 
Agreed - dry rot can be terminal. The book says cut away all timber six feet away from where you perceive the end of the problem to be and you might just get rid of it. There is also a distinctive smell - and usually ripples in the outside of the hull. One moral of tale is to ensure decent air circulation in fusty corners.

You have my sympathy - dry rot can finish a boat if not hit hard ... and expensively. OF
 
Thanks :eek: 2 very scary replies!! I've just had the big knife out and there doesn't appear to be any damage to the wood thank goodness.... as far as I can see anyway. If the news stays good when I take everything out I still need to figure out what to do about not spreading it by just scraping it off and transferring it into the bilges. I could do with some kind of contact killer spray if such a product exists.
 
I've no experience of dry rot in boats, but I have in buildings.

In one, an old church, we removed many tons of timber, then about three foot of earth, took plaster off the walls, then used an industrial burner on the walls. Then used cuprinol. We sold the building, but some years later, the roof fell in.

Dry rot is serious and very hard to stop.

I hope I have not spoiled your day.
 
I've been reflecting on your problem over night. It is possible that you don't have dry rot at all. The first thing that I'd do is dry it all out. Then I think I'd strip the paint off and have a good look at the wood underneath. If the wood is sound, I'd just give it a really good soaking with 5* Cuprinol. If you get the distinctive small of dry rot and the wood is crumbling, you have no option but to cut it out and go back as far as you can - six feet into solid timber is enough! When you reassemble make sure that ventilation is sufficient. OF
 
Not an expert but have had conversations with several. Dry rot in timber usually produces a very distinctive pattern of decay; the affected timber fractures both along AND across the grain giving a kind of chequered appearance. The timber will usually crumble quite easily. Although it's called dry rot moisture is required to start it off.

HTH, good luck.
 
stuhaynes said:
Thanks :eek: 2 very scary replies!! I've just had the big knife out and there doesn't appear to be any damage to the wood thank goodness.... as far as I can see anyway. If the news stays good when I take everything out I still need to figure out what to do about not spreading it by just scraping it off and transferring it into the bilges. I could do with some kind of contact killer spray if such a product exists.
Click to expand...

OK, dry rot is very, very serious! :( Dry rot is not dry, it is very wet.

It is called dry rot as the timber, when infected, looks very similar to wood that has been slowly converted to charcoal. It has a cuboid structure and appearance along the grain but is not dry, in fact it carries a load of moisture which in turn carries the fungal tendrils! :eek:

I suffered a serious dry rot infection in the ground floor timber joists in my very first house and know a thing or two about it. :mad: Timber has to be very carefully cut out and burnt and the usual talk in the building trade is to cut back about a metre from the visible infected areas in all directions! Test any infection or suspect timber with a sharp awl or thin screwdriver. Deal with any tools that you might use as mentioned below.

Treat the area you are working in as if it has an serious infectious disease as your hands and clothes can carry the spores to new timber not yet infected!! :eek:

Pictures of dry rot here:

http://images.google.com/images?hl=...bv=2&aq=0&aqi=g3g-m1&aql=&oq=dry+rot&gs_rfai=

and Wikipedia here:

http://en.wikipedia.org/wiki/Dry_rot

Ventilate with great care and don't blow any fruiting fungal spores about your vessel. Use thin medical gloves to handle any infected wood and destroy gloves after use on a daily basis.

http://www.medisupplies.co.uk/acatalog/Value_Powdered_Latex.html#aTOP0048

Any tools you use (wood saw, awl, hammer etc) can be gently 'flame' treated after use and also left out in the sun for further UV treatment.

Any solution with copper in it will stop mild fungal infection AFTER you have rid the boat of serious infection.

I really hope for your sake it is NOT dry rot? :confused:
 
Don't get too stressed :)

Wooden boats rot, they need fixing, that's life. See caring for your boat as part of the price of owning something with some history. The trick is keeping on top of rot and not ignoring it.

Have a good probe with a bradawl around all of the area you've found. If the wood is soft it needs replacing.

Speaking as somebody who's working through the repairs from the rot I found in my boat, I'd say don't ignore it, but don't panic either. Read around *a lot* on the subject and you'll soon start to develop an opinion of your own.

Good luck!

Chris
 
lenseman said:
OK, dry rot is very, very serious! :( Dry rot is not dry, it is very wet.

It is called dry rot as the timber, when infected, looks very similar to wood that has been slowly converted to charcoal. It has a cuboid structure and appearance along the grain but is not dry, in fact it carries a load of moisture which in turn carries the fungal tendrils! :eek:

I suffered a serious dry rot infection in the ground floor timber joists in my very first house and know a thing or two about it. :mad: Timber has to be very carefully cut out and burnt and the usual talk in the building trade is to cut back about a metre from the visible infected areas in all directions! Test any infection or suspect timber with a sharp awl or thin screwdriver. Deal with any tools that you might use as mentioned below.

Treat the area you are working in as if it has an serious infectious disease as your hands and clothes can carry the spores to new timber not yet infected!! :eek:

Pictures of dry rot here:

http://images.google.com/images?hl=...bv=2&aq=0&aqi=g3g-m1&aql=&oq=dry+rot&gs_rfai=

and Wikipedia here:

http://en.wikipedia.org/wiki/Dry_rot

Ventilate with great care and don't blow any fruiting fungal spores about your vessel. Use thin medical gloves to handle any infected wood and destroy gloves after use on a daily basis.

http://www.medisupplies.co.uk/acatalog/Value_Powdered_Latex.html#aTOP0048

Any tools you use (wood saw, awl, hammer etc) can be gently 'flame' treated after use and also left out in the sun for further UV treatment.

Any solution with copper in it will stop mild fungal infection AFTER you have rid the boat of serious infection.

I really hope for your sake it is NOT dry rot? :confused:
Click to expand...

I'm not certain that is is dry rot, but I'm going to treat it as if it is. I've spoken or emailed various companies and organisations about this and the consensus appears to be this:

Dry rot needs three conditions to thrive.
1. Food (wood)
2. Moisture / particularly wetted timber. As in timber already affected by water.
3. An acceptable temperature and low ventilation levels.

The consensus continues with the recommendation to use Boron based products to kill the problem. I'm looking now to see what after treatment I should use, as in primers and finishing coat after stripping. All of the wood appears to be completely sound but I intend to give it some serious attention with a blow lamp, apparantly it can be killed at 40c.

I've started pre treatment by (gentle) forced ventilation of the area. I'm going to do this for the next 2 weeks. The gradual moisture reduction will slow the 'infection', whatever it is, then I'm going to kill it. I hope! ;)

The questions I need answering are; how long should the Boron ( or other product, if there's one better ) be left before a primer coat. Is 'proper' lead paint a suitable primer. What gloss paint is the most suitable anti-fungal. I've not had an answer to these questions yet, and I can't afford to get it wrong!

Thanks for the responses so far, a problem shared......
 
Long while since I dealt with this stuff and really hope it is not dry rot. A local building surveyor should be able to get a sample tested/inspected to see if it actually is dry rot. The reason for needing to treat up to 2metres away is that the dry rot can spread its white tentacles (mycellium) that far and transfer moisture to carry on the rotting process. The mycellium can break through brick work etc. It does take more than a closed space to cause rot you need damp unprotected wood as well. Also when clearing it out no point worrying about spreading it further because if it has sporred the millions of microscope spores will be all over your boat. Is the rot in cheap ply or has some one used some softwood to hold joinery together? If so get rid. What ever you do with this do not cut corners.
Good luck.
Just read your last post: If it where mine: check meticulously for rot: any must go. As long as the wood is dry enough to take paint then I would use any good quality oil based primer after using a clear wood preservative. Then what ever you want on top but proper paints, under coat and gloss not one pot solutions. You could also try and borrow a wood moisture meter, wood will not rot below 20% (or 18 cannot remember) and seem to recall most household timber outdoors would be around the 14-16% and interior wood will be around 8%. Not sure what timber on a boat would be but would expect timber inside to be below 16%. I would also want to find out why the wood is so wet in the first place.
GL
 
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I'm a cynic. Borates are usually considered to be more 'eco-friendly', an expression I often associate as a euphemism for being less effective. I have used it on my own boat - so have some experience.

You can inject boron pastes into the wood for severe problems but the general theory is that the boron salts wash into your wood with water. This is where my logic parts company - if the boron can wash into your wood it can wash out again too. I have reverted - dry out the area well and give a good soaking with 5* Cuprinol - hoping to get the Cupinol absorbed as far as possible into the wood. Since the Cuprinol is oil based it shouldn't wash out as quickly as the borates A garden spray with a wand usually helps get it into the difficult corners. OF
 
On a more optimistic note. Dry rot is quite unusual on a boat and this winter has been a spectacular one for condensation and therefore mould everywhere, especially in ill ventilated areas against the skin.
May I suggest that you post a couple of clear piccies before further speculation ?

Btw, dry rot spores are everywhere, in the air. But for Dry Rot proper to take hold you need damp, dark and poor ventilation, which is why through draught is so important in buildings and boats and why it is typically found in floor joists, bricks etc close above bare earth where the underfloor vents in a house have been allowed to block up.

I would hazard a guess that you have impressive mildew and mould along the caulking lines. Warm water and bleach on all surfaces will stop that.
Once you see little cracks across the grain of the wood ( as said) then is the time to worry, piccies first.
 
I recently did some major renovations to a house removing a first floor full of dry rot and I would agree with blue boatman,this is unlikely to be dry rot if the timber is sound.The timber I removed from the house was completely wrecked and decayed.There was also a big fruiting body in the house like a large red mushroom.If there is no decayed or rotten timber I dont think it is dry rot.Be wary of companies telling you that u have dry rot,they may be seking some work !
 
Thanks everyone for the comments so far. I'm a few days into gently forced ventilation and at least 2 weeks away from stripping the whole bow cabin. It's got to be done but I can't say I'm looking forward to it. Pictures are not possible yet but I will post some when I've stripped everything back.
Does anyone have a view about the use of red lead paint (the proper stuff) as a follow up after the wood treatment? When the boat was built Wilsons did the whole of the inside with pink lead, which was common practice then.
 
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