Localised dry rot...

[Johnmelad502]

Went on a job today, where I was supposed to level a bathroom floor but ended up removing the bath loo and sink, having found some serious wet rot.

Having removed some floor boards I then found some localised dry rot.

What's available (off the shelf and where) to treat the area affected and the surrounding area. I am replacing all timber with tanalised throughout the bathroom.

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[^woody^]

You wont be able to just brush on some fungicide. Jut adding tanalised timber wont be any good.

Dry rot has to be treated by removing at least 1m of timber past the rot, and the walls steralised by injecting the whole thickness of the walls with fungicide - holes at 300mm horizontally and 150mm vertically, and solution pumped in according the manufacturers guidance

Steralisation may have to include [behind] plaster too

 

[mpaton2009]

Having had a nasty outbreak of dry rot myself just recently, and reading hundreds of articles on the subject, there is a lot of conflicting information on whether full on masonry sterilisation actually has any benefits if the masonry itself is dry and the food sources of the rot (ie damp wood) are eliminated - the rot will die naturally and you save saturating walls with water (which can cause further damp problems elsewhere in the building)

that joist is knackered tho, my old ones were the same (embedded into the masonry), the end (+ 1m) will need to come out and new spliced in with DPC wrap or joist hangars

 

[alittlerespect]

You would be well advised to steralise the walls as recommended.
Regretfully once established dry rot can survive on the moisture present in air alone - hence the term 'dry rot'. There does not need to be any damp/moisture present to encourage further growth. Dry rot will penetrate brickwork and can easily travel vertically and horizontally between the interface of the brickwork and wall plaster and if not fully eradicated/treated you will find it coming back to haunt you in a few years.

From the photographs you do not have a serious problem at this time however you should get a reputable company with an insurance backed guarantee to carry out any remedial treatment.

One final comment, look for the causes behind the occurence, there will be no point in carrying out the remedial repairs if the conditions that led to the outbreak of dry rot are not dealt with. For example is the oversite damp, did a rubberised/vinyl floor covering trap the air and with the damp oversite lead to a high level of humidity in the floor void - is the floor void ventilated sufficiently You also have an opportunity to concrete over the oversite!


Regards

 

[JohnD]

read http://www.cuprinol.co.uk/treatment/wet_dry_rot.jsp

and http://www.cuprinol.co.uk/treatment/treat_dry_rot.jsp

http://www.cuprinol.co.uk/products/5_star_complete_overview.jsp

http://www.cuprinol.co.uk/products/5_star_complete_usage.jsp

http://www.cuprinol.co.uk/advice/index.jsp

 

[mpaton2009]

You would be well advised to steralise the walls as recommended.
Regretfully once established dry rot can survive on the moisture present in air alone - hence the term 'dry rot'. There does not need to be any damp/moisture present to encourage further growth.

Sorry but that's claptrap. Moisture and a food source (i.e wood) is a _key_ factor in the survival of any wood-decaying fungi. Dry rot does not "just exist" without these factors. Get rid of either one and it disappears.

Dry rot /cannot/ affect dry wood!

 

[alittlerespect]

I hate to disagree as it goes against my rather placid nature - but why the hell not - mpaton2009 needs to do a lot more research before he/she goes making such a critical statement, after all, all I ask is for alittlerespect!

Dry rot is a fungus and once established in timber because of poor environmental conditions i.e. humid and stagnant conditions it can and will propogate and is more than capable of surving on the water vapour in air alone as it feeds off the cellulose structure of the timber.
Dry rot can travel incredible distances and through bricks and mortar and will even traverse metal elements in its journey to find new food, and as such will wreak havoc within any building if left untreated.
For example, if you walk into a room with bare floor boards and your foot disappears as you walk onto a board, you will know that you have a problem with dry rot (and that is just the start - if it gets to the structural timbers then you will really have a serious problem to contend with!) This fungus that will eat the heart out of timber while leaving the surface looking quite alright and destroying its structural integrity.

Once established dry rot can turn into a home owners living nightmare, even with the best will in the world there is no guarantee that there will not be a re-ocurrence (ok you may get a paper guarantee from the specialist treatment company, but dry rot won't pay any attention to what is written on the paper!)

Regards

 

[gregers]

(ok you may get a paper guarantee from the specialist treatment company, but dry rot won't pay any attention to what is written on the paper!)


i have even seen dry rot growing in an outside concrete path that was totally infected from the house about 1m away.
the best way of discribing true dry rot(Serpula lacrymans)used to be called merryillis (sp)lacrymans)is a cancer that will concour everything if not treated.

 

[stuart45]

BRE have done a lot of research into dry rot over the years, and their advice is that the primary measures are to remove the cause of the moisture and rapid drying of the structure. Secondary measures include removing the rotted timber and replacing with treated timbers as well as treating the sound timbers. If further wetting of the structure is avoided it may not be necessary to treat the walls.
This is part of the advice given in Digest 299.

 

[mpaton2009]

I hate to disagree as it goes against my rather placid nature - but why the hell not - mpaton2009 needs to do a lot more research before he/she goes making such a critical statement, after all, all I ask is for alittlerespect!

Dry rot is a fungus and once established in timber because of poor environmental conditions i.e. humid and stagnant conditions it can and will propogate and is more than capable of surving on the water vapour in air alone as it feeds off the cellulose structure of the timber.
Dry rot can travel incredible distances and through bricks and mortar and will even traverse metal elements in its journey to find new food, and as such will wreak havoc within any building if left untreated.
For example, if you walk into a room with bare floor boards and your foot disappears as you walk onto a board, you will know that you have a problem with dry rot (and that is just the start - if it gets to the structural timbers then you will really have a serious problem to contend with!) This fungus that will eat the heart out of timber while leaving the surface looking quite alright and destroying its structural integrity.

Once established dry rot can turn into a home owners living nightmare, even with the best will in the world there is no guarantee that there will not be a re-ocurrence (ok you may get a paper guarantee from the specialist treatment company, but dry rot won't pay any attention to what is written on the paper!)

Regards

Apologies for being a little flippant.

I still stand firm though - while you are correct that dry not is best supported in humid and stagnant conditions it absolutely cannot infest dry wood. It's like having a fire without one part of the fire triangle. If this were true, every piece of wood in the whole country would be infested with all sorts of rot (not just S. Lacrymans) due to the millions of natural spores that are present in the air.

The conditions for dry rot have to be very specific which is why it is relatively rare compared to wet rot:

DAMP timber of ~ 20% moisture content, much higher or lower and dry rot will cease to propagate.

STAGNANT air - if you have good ventilation, dry rot will not happen.

Get rid of either condition, the fungus eventually dies, treatment or no treatment.

 

[mpaton2009]

(ok you may get a paper guarantee from the specialist treatment company, but dry rot won't pay any attention to what is written on the paper!)


i have even seen dry rot growing in an outside concrete path that was totally infected from the house about 1m away.
the best way of discribing true dry rot(Serpula lacrymans)used to be called merryillis (sp)lacrymans)is a cancer that will concour everything if not treated.

That almost certainly won't have been dry rot - it cannot survive outside (except in the absolute rarest of conditions which most climates will not provide)

 

[gregers]

(ok you may get a paper guarantee from the specialist treatment company, but dry rot won't pay any attention to what is written on the paper!)


i have even seen dry rot growing in an outside concrete path that was totally infected from the house about 1m away.
the best way of discribing true dry rot(Serpula lacrymans)used to be called merryillis (sp)lacrymans)is a cancer that will concour everything if not treated.

That almost certainly won't have been dry rot - it cannot survive outside (except in the absolute rarest of conditions which most climates will not provide)

mmmm really...........
the fact that it was sent off for lab tests proved it was dry rot,so yeah i think it was.we were sufferering from the same illusions as yourself,this was a major outbreak that infected a large part of the rear of the house and started from the sewers overflowing and filling up the cavitys.then drying out and hey presto perfect conditions for it to start.

and it will search for new food,even if it means creeping over treated timber/tanilized,now this knowledge is from training and doing from years back,unless they now know different ill keep on offering advice and doing it how i was trained to.never did like the containment method though(personal opinion).
back in the day when i used to do this,the firm i worked(big firm) for had a big job on an office/converted block to treat and they missed a bit,about 9 mths later it blew up in there faces and cost them thousands to rip out and retreat.