Any way to halt wood rot?

I'm repairing, for the second time, a window frame in my 140 year old house. About 6 years ago I carefully cut and chiselled out all the rot I could find, and machined up wood to integrate it all back as if nothing had happened. At the time I tried common bleach on the remaining timber to stop progression of the rot, but this has failed, and here I am again about to repeat the first exercise.

So the question is whether there is any proven chemical to brush into the freshly cut faces of the timber that will kill the rot?

Hi JB. I use this product all the time

EARL’S(R) WOOD HARDENER(R) – Timbermate Group

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Originally Posted by Mountain Ash

Hi JB. I use this product all the time

EARL’S(R) WOOD HARDENER(R) – Timbermate Group

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Fascinating - I had not heard of it before. What I can't tell from their literature is whether it kills the cause of the rot, or just hardens up the existing soft resultant wood so that a simple repair can be done.

I use it (as per the instructions funnily enough :rolleyes:) after all the soft spongy stuff is removed. Once the repair has been made and water can no longer access the problem area, the rot should be dealt with. Using bleach will kill mould etc but it is the continued access of water that can't dry out that perpetuates the rotting. Window sills are a great example

There was a Csiro developed product called blue 7 for rot prevention.

There's probably similar products available today.
The problem with mould etc is the spores can be deeper than visible, so even mechanical removal of damaged wood may leave some.
Sealing the wood will no doubt slow it, (and is essential) but dry wood still has moisture in it, so that alone may not guarantee a permanent fix.

It is the unseen spours that cause the rot to continue, even after the punky timber has been removed or treated. 50mm of sound timber removed from all directions will usually be enough. Of course, in a lot of cases this goes beyond the dimensions of the piece of timber, in which case, replacement rather than repair is necessary.

There is Wet Rot & Dry Rot, Wet Rot just needs you to remove the water (moisture) which is feeding it and it will dry out and stop decaying your timber, then cut out the effected areas and splice in new timber sections, if it's to be painted use a good quality durable hardwood to make the repairs that will accept a paint finish. Dry Rot, which I have not heard people mention in Australia, is much harder to get rid of because it can either travel through dry areas looking for moisture or send out airborne spores, I have had to deal with Dry Rot in a couple of buildings I bought, which involved finding the main fruiting body (which in my case was attached to a masonry wall) and drill a circle of holes around it (about 100mm apart) and then inject these holes with a chemical to stop the fruiting body from spreading or starting again somewhere else.

Your problem is commonly called dry rot although it needs persistent moisture to occur. You need to fix both the cause and the problem.

The cause: This usually means damage to the flashing on the window frame and/or damage to the flat areas (sills or sash tops) where moisture can pool. Stop this persistent moisture.

Existing damage: Windows in the 1880's were commonly made from pine or cedar, rarely hardwood. Fix as you have done with the same or a similar species. Do not splice hardwood into softwood as the joint will not last.

Innoculate: Strip all paint from the frames and de-oil with a strong solvent such as acetone. Then apply multiple coats of a penetrating fungicide (rot is fungal action). Tributyltin was brilliant in a sealed environment but was banned in the 1990's; a specialist paint supplier or yacht chandlery should be able to advise on what to use. Staff at BigChains may pretend they have the knowledge! I apply multiple coats while wet and keep painting until it stops soaking in.

Seal: Seal the surface with a penetrating sealant like Everdure (2 coats).
Everdure Epoxy Resin Wood Primer | International

Paint: Good quality undercoat and at least 2 coats of high gloss.

Hi Jabell,

When you say you repaired the windows 6 years ago and rot as now returned, I assumed this new rot was in your new spliced in timber and not your old frame, that is why I suggested using hardwood, because in the 1880 timber was sourced from more mature trees than the farmed plantation trees of today. While hardwood may be more stable than softwood thus movement in hardwood will be less this will be marginal on the window sections that are being spliced and the paint will also seal the timber from moisture, in reality using a farmed modern day softwood could move more than your old 1880 frames. I doubt that it is Dry Rot because it will not have waited 6 years to return it would have continued looking for moisture and you would have a fruiting body (sporophore) somewhere in your building. You are more likely to have the more common Wet Rot and it will have returned because the areas on your windows that got the rot in the first place will be subject to a lot of rain and sun which will breakdown the paint and let moisture back into your new spliced in timber. Timber in this type of environment needs painting every year, because the paint starts to deteriorate and stops protecting your wood.

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Originally Posted by jabell

I'm repairing, for the second time, a window frame in my 140 year old house. About 6 years ago I carefully cut and chiselled out all the rot I could find, and machined up wood to integrate it all back as if nothing had happened. At the time I tried common bleach on the remaining timber to stop progression of the rot, but this has failed, and here I am again about to repeat the first exercise.

So the question is whether there is any proven chemical to brush into the freshly cut faces of the timber that will kill the rot?

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Yes there is stuff you can use but it seems nothing is permanent.

If its the new wood rotted then you havent stopped the water source or used a treated piece of wood replacement.

But if its the old wood cut as much back as you can first . Someone said go 50mm past last of rot but ive read and been told 100mm past last rot if possible

Theres 3 types of rot -wet rot needs lots of water and once water source stopped generally stops
dry rot - hard to see and only needs minimum moisture content -around 20-30 % and can get rest from wood and air.

If its old wood not cut out rotting then its probably dry rot and you didnt cut it back enough or use a decent fungicide - forget bleach.

But it seems Boric Acid is most commonly recommended fungicide.



Heres my response to a friend here in NZ about a turbo wood hardener available in NZ he was going to try. He has has used Metalex green in the past (CopperNaphthenate) which im about to do;

I stayed away from woodhardeners because

1. they seem designed to restrengthen wood which isnt my main goal as I want kill any rot on the edges of my cutting out wood where I cant go any further and these products dont seem to mention fungicide killing
2. Theres the 2 different types of rot that destroy wood differently and these products probably only repair one of them .
   dry rot (aka brown rot) destroys the cellulose in wood
   wet rot (aka soft rot) destroys the lignin in the wood

1. According to a guy on property talk chat forum website , epoxy products dont fix the cellulose problem aka dry rot . I dont know if they are epoxy or not. Heres his reply to a guy boasting about earls wood hardner.

Originally posted by friendly_prawnView Post
a brilliant tip.. I don't know why, actually I do know why builders don't recommend this stuff.. It would cost them a lot of work. My mum just spent $1000 replacing a rotten window frame. If only I had of known about this stuff. It's amazing stuff. http://www.youtube.com/watch?v=Jq5wlpKOmmc So any of you guys that have a bit of rot in a window sill etc, and are told by the carpenter it needs replacing, bollocks... I tried it the other day and was amazed with the results... Absolutely brilliant.. I seen a clip on youtube where an American product of exactly the same type of stuff was used on a structural beam. I thought they were crazy.. But after the repair I could understand why.. CAnt find the clip again or I would post it. Apparently that earls wood harderner is not supposed to be used on anything structural but I guess they have to say that just incase.. I got a support beam on my deck Im almost tempted to use it on.. Not quite brave enough to use it on anything structural myself... But highly recommended for any rot that isn't structural.. It will save you a lot of money in unnecessary repairs...




Hardness and Strength are two completely different properties of materials. It is common to confuse the two but they are distinct and unrelated. Hardness relates to the ability of a material to withstand scratches and dents. Strength is the ability of a material to withstand an applied load without failure.

Composite materials can be incredibly strong and are made up generally of two or more very different materials with very different natural properties. One material acts as a matrix that binds and holds the other material which may well be a fibre. When an epoxy matrix is combined with fibre reinforcing, the composite material has properties far in excess of its separate individual components simply added together.

Wood is a natural composite of cellulose fibres in a lignin matrix. Depending on the type of decay, rot will take out either the cellulose or lignin first and leave behind the other (e.g brown rot vs soft rot). Untreated timber is generally hit by brown rot first, so the cellulose fibre is consumed leaving behind a brittle matrix of lignin. Filling this with epoxy will give you a matrix reinforced with more matrix, and is therefore not reinforced as it is not a composite and has only a fraction of the strength of the original timber.

I strongly advise you to not use it on your deck beam if it is rotten, either replace the beam, or put another one beside it.

A few other points:
1. Why did it rot in the first place? You have to fix the source of the leak first, then repair the frame otherwise it will just happen again.
2. If you don't remove all the rot you should try an in situ treatment on the timber to stop it from spreading further.
3. It is non toxic "when cured".

Other than that, looks like a good product.


Wood hardener -

PropertyTalk.com


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Different wood rot explained here in detail;
Wood Decay in Trees | Forest Pathology


Dry rot looks is way harder to get rid of as can be harder to spot and eliminate/cut out.


Most websites recommend boric acid to treat rot
but Copper Naphthenate which is what green Metalex is (the clear is Zinc Naphthenate 60%, ) has also been mentioned
Rot Repair in Wooden Boats - The Rot Doctor



This one recommends mixing them together I think – I only read conclusion

https://static1.squarespace.com/stat...nd+Synergy.pdf

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Originally Posted by russ57

The problem with mould etc is the spores can be deeper than visible, so even mechanical removal of damaged wood may leave some.
Sealing the wood will no doubt slow it, (and is essential) but dry wood still has moisture in it, so that alone may not guarantee a permanent fix.

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This.

The problem with moulds that infect wood is the rhizoids travel up the cellular tissue a relatively long way, much further than any mould killer can wick up the wood... That mould will continue to live and produce spores that will lay dormant in unfavourable seasons, waiting for the right moisture level to be present and off it goes again, and again, and again... You can't seal the wood, regardless of what any product says and prevent the mould from continuing after it's already infected the wood. It might slow it down but that's it. High humidity is often all mould needs, not soaking wet wood to flourish. And humidity as we all know will still absorb into wood, even after we finish it.

The only way to guarantee you stop the rot is to cut well beyond the known rot and replace the affected wood, preferably with wood that's been treated and rated for exterior use. Slather the area in an antifungal. And just as important, deal with the moisture problems the window frames are having. Just don't do what I see so many DIY people do. Pump copious amounts of Sikaflex (tm), gap filler, or silicone into the gaps and hope it keeps the water out - it won't. Often it has the opposite effect and keeps the moisture in.

As noted above, borates will treat the fungal growth. You need to remove all unsound timber and mke any needed repairs. In the original timber that remains, you can drill a series of holes and insert boron based rods. This will slowly release into the remaining timber and stop the fungal growth.

See here for examples:
Preschem No-Rot Wood Preservative Rods | Bowens
Bor-8 Rods | Borate Rods - System Three Resins
System Three 1/4-Inch by 1/2-Inch Wood Care Borate Rods, 12-Pack, 14112 : Amazon.com.au: Home Improvement

Here is an abstract of study showing effectiveness:
Long-term performance of fused borate rods for limiting internal decay in Douglas-fir utility poles - University of the Sunshine Coast, Queensland (usc.edu.au)

And so/me more info:
PowerPoint Presentation (illinois.edu)