Anyone any experience of treating something like this? Our near 200 year old house has it under the living room. I see some of the joists have rotted and new ones have been placed alongside, timber props have been used also which are covered in the stuff at the bottom.
mark
sorry......
Last time I treated any it was 30 years ago (treatments may have changed !) - but we flooded the area with some foul-smelling fungicide several times after taking a blowtorch to the fungus that was visible on the surface.
In our case the darn stuff had actually made its way _through_ the bricks, and was visible inside broken bricks.... real 'Dr Who' stuff !
I'd have thought that you'd also want to remove all the infected timber - not simply 'feed' the fungus by nailing nice new fresh timber to the old infected stuff.....
Good luck ! Adrian
Jon.
There's 2 air bricks right near where all the mycelium is. I can't see any water pools and it also appears the radiator pipes aren't leaking but I will be checking again as the radiator is right above where all the mould is.
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wet wall by the looks of it. The joist has been replaced, but I'm not sure why the rotted one was left behind -- that looks like a bad idea.
resting directly on the damp earth, and the wood off-cuts and shavings which are down there, combined with no ventilation. It's been caused by bad workmanship in repairing the earlier wet rot. It's been caught early and doesn't look too bad.
All the debris and the two rotting supports need removing. Don't allow any infected timber or mycelium to come into contact with uninfected timber (bag it under the floor and lift out without spilling any). (You don't need to get all the growth on the soil/brickwork out -- it will die in the absence of any timber in contact to feed on. People often play a blow lamp over it, although I doubt you'll get it all that way as it will go down into the soil.)
I would get at least one, and if possible two air bricks into the subfloor in that dead-air corner. The floor joists want supporting using joist hangers on the wall, and the ends of the joists wrapping in a damp-proof membrane to prevent moisture entering from the wall.
The dry rot should then die, through lack of wet timber to feed on and ventilation keeping the remaining timber dry. I would keep an eye on it though (you can look through the airbricks if you use ones with clip on grills).
Check the rest of the subfloor too, both for any more dry rot, and any other poorly ventilated areas which could use more air bricks.
'sinking' of the wood in the infected area?
To eradicate this, you will need to carry out the following:
Note these steps are simply advisory and can differ according to the level of infection.
1 Remove all loose debris from the area - put it into sealed plastic bags if you have to carry through the property. 2 Remove all infected timber to a least a metre back from the last signs of the fungus - again ensure that the stuff is in bags as in 1 above. 3 Use a blow torch on any brickwork and the floor to burn off the fungus to at least a metre back from the last signs of the stuff. 4 Coat all the brickwork and floors with a chemical dry rot killer (ensure protective clothing is worn) - and as the dry rot will penetrate through brickwork and concrete, follow the manufacturers instructions implicitly. 5 Coat any remaining timber with the chemical. 6 When replacing the damaged timber, ensure that is also chemically treated before fixing - and treat any cut ends before fixing. 7 If you have to re-render or insert new bricks/airbricks, ensure that there is dry-rot killer in the water used for mixing the sand/cement compo. 8 Unsure you have a good air flow to the under-floor by fitting more airbricks.Have a look at this site for a little more information on identification etc.
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I don't like it.
Typical mess under the floor and nothing to stop the damp from rising from a high water table. New wood doesn't seem to have been treated either, by the look of things.
I assume there's no dpc.
Thanks, can you recommend a chemical dry rot killer to use?
Also, I take it I have to remove all the joists ends where there are signs of dry rot?? If so, it is advisable to repair the joists using props (either timber or steel) or fix the joists using brackets like these:
correct, tradesman seem to have a habit of throwing their junk in floor cavities and also doing the least amount of work possible to get the job done. :-/
the only part of the floor that will come up easily is the part you can see in the picture
we can do, you mean simply cover the ground with a polythene DPM sheet and lay bricks on top?
a lot of the joists are rotted so it would mean removing a lot of them. As you can see the previous repairer just attached new wood to the rotted timber without removing it. :-(
Are they clear? And do they allow a cross flow of air from one side of the floor void to the other. Both open on the same face of building won't really ventilate the space particulary well. Opposite sides is best but adjacent at a pinch.
Damp is a fact of life in a 200 year old building, they didn't do damp proof courses then. They just built straight into/on the ground.
Definitely.
There are two main things to do to avoid wood rot in general.
1) Make sure that there is plenty of ventilation. Unblock and add air bricks.2) Remove sources of moisture. This can fall into several categories.
a) Check the ground level outside. It's very common that this will have been raised over the years by there being paths, garden and so on. You can lower it, if necessary just adjacent to the house by digging a trench and filling it with shingle to assist drainage.
b) Check that there is no penetrating damp from leaking downpipes etc.
c) Isolate the timbers from the source of damp. One good way is not to have the timbers going into the outside wall at all and also to avoid the timber prop bodge that was done previously. This can be done by building a sleeper wall running perpendicular to the joists and about 300-500mm in from the outside wall, running parallel to it. This needs ideally to be constructed from hard engineering bricks and arranged to have an open bond - i.e. gap horizontally between each few bricks again for ventilation. A length of DPC material can be run along the top and then the joists rested on that. Cut them back from the outside wall leaving a gap of 20-30mm.
This method is effective and is the least disruptive to the floor since it can be implemented by removing a few floor boards at the edge.
All of this assumes removing infected material as others have suggested and thoroughly disinfecting the area. Cuprinol solvent based fluid is effective.
For any new timber, buy known pressure treated stuff from a timber merchant selling constructional timber, not a DIY store.
Mark,
My advice, is that if you have dry rot infected wood (of any type and especially structural) is to remove it and replace it with new and suitably treated - it's possible for the fungi spores to be deeply embedded in the wood for some distance away from where the fungus is showing.
I sorry, I cannot recommend any particular chemical - the reason being is that when I took early retirement (7 years ago) I left all that information in my old office ready for my successor, and if I recall correctly, it was only supplied to 'the trade' due to the COSSH regulations :-(
A quick Google has thrown up this link to Rentokill which may me of some use to you:
My sincere advice would be to at least get a professional survey done along with a quotation on the cost because if you fail to eradicate it first time around, things can be made worse by carrying the fungus spores around your property on your clothes and shoes - and contrary to popular belief, it doesn't need a dark place to propagate and survive.
[1] Many people, including some so-called professionals, wrongly identify dry rot when in fact it is wet-rot.All the best with it
Brian G
While that all looks quite nasty, I have a suspicion is is not as bad as it first appears. The stuff on the floor certainly looks like dry rot - but quite possibly in the very early stages - there are no fruiting bodies visible, and it does not look like it has spread that far since most of the timber on the vertical struts is still sound (although that will not last long, so prompt action is required here!)
The damage to the joist ends however, looks more like the result of ordinary wet rot - probably a result of contact with what looks like moist brickwork.
With either type of rot, cutting off the supply of water is the most important first step.
After that, getting rid of all infected material (and 1m beyond), then chemically treating what's left is the usual remedy.
Also those vertical timbers are a bodge. They should never have been there in the first place.
The house is built on damp soil, as are millions of houses. If you remove it, the house will collapse.
This is unnecessary. The house survived for 200 years, and dry rot only set in when some workman did a bad job. You only need to correct that, as it looks like it hasn't spread very far yet.
The joists look like wet rot (can't tell for sure from the pictures, but I don't see any sign of dry rot on them). Whilst it would have been more professional to strip them out, you can leave them where they are providing they are no longer getting wet.
This isn't necessary. Dry rot will only grow in quite limited conditions and all you need to do is to change the environment there so the conditions are wrong for dry rot growth (in this case, timber in contact with moist soil). Growth here has only happened due to the bodged repair for wet rot at an earlier stage. It needs a source of moisture and timber in order to grow. Whilst it needs a piece of damp wood to start growing, the hyphae which consume and grow out from the infected timber in search of more timber to eat can carry the moisture required to drier timber (hence the name). Providing the house timber is not getting damp (ventilated and not in contact with damp soil or brickwork) and there is no infected timber left in contact with moisture to enable hyphae to grow to the dry timber, you will be OK.
Dry rot originates in caves in the himalayas, where it eats dead tree roots. It was brought back to the UK (and many parts of the world) in wooden goods, and also infected the wooden ships which carried them. It needs very specific conditions to grow which don't exist naturally in the UK. However, they can be found in the man-made micro-climates in some buildings. You just need to disrupt those ideal micro climates, which isn't very difficult in many cases.
There are no magic bullet chemicals which prevent dry rot. The chemicals which do exist just work by being very toxic to everything, and you probably don't want those poured around your home, and they haven't been available to the public for a few years now anyway.
Dry rot, like damp, is something the treatment companies love to scare you with, and you will hear lots of stories of people having excessive treatments carried out at great expence and disruption.
I wouldn't do that you'll be trapping the moisture from the ground underneath it making a nice damp enviroment for the fungus to live in...
Removing the visible fungus and all the timber that it has been in contact with and sloshing chemicals about will help but what you really want to do is make the conditions such that they are not suitable for the thing to grow. ie. dry. which means decent ventilation and timbers isolated from sources of damp by physical separation or damp proof layers, DPC membrane or slate to rest joists on etc.
Air bricks are only on 1 side, under the other side of the house(under the kitchen) is a valuted cellar and there's no way to get air bricks in there because of the thickness of the bricks in the valut.
It doesn't feel damp under the living room though, there's quite a draft. The cellar is a PITA
The joists are very crumbly, I can easily brake bits off by hand. Is this not dry rot?
Also, we have something that looks like this on the wall near the joists:
thanks for your advice.
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