dry rot

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Does anyone have any dry-rot DIY experience?
I have a cottage that shares a wall with the main house. The cottage is full of wet and dry rot, mostly caused by leaking roof and broken gutters. The dry rot has come through the shared wall and is in the joists of the ground floor of the main house.
I am happy to fix the original leaks, etc.but am wondering about tackling the dry-rot myself?
Any help appreciated.
Cheers! Stuart.
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Well, it's a case of removing the source of the damp, making sure all areas containing timber are well ventilated, and then it will die. You will need to replace the infected timber as it will have been weakened and could rapidly start a new outbreak if it gets damp (ideally with pressure treated timber, and after the brickwork has dried out).
You cannot really just do this on one side of a party wall though -- at least the investigation for sources of damp and ventilation must take place on both sides, and checking for extent of spread.
--
Andrew Gabriel


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Thanks Andrew,
Any idea of how long it will take to die out? how long should I leave the brickwork to dry out before replacing the infected wood?
Are you saying that if I stop the damp source, let dry out, replace infected wood, and keep ventilated, then there is no need to apply the 'toxic box' chemicals? It is the chemical application that seems to cost big money to get a contractor to do, and if it doesnt need done, then the whole job becomes a lot more DIY friendly.
Thanks, Stuart.
PS. I will be fixing both sides of the wall, as (un)fortunately, the cottage came with the house!
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Depends how thick the wall is, and how wet. A rough ball-park figure is that a brick wall dries out at around 1 week per inch thickness once well ventilated. If you reconstruct with no timber in contact with the wall (e.g. using joist hangers, membrane barrier protection, etc), then waiting for the wall to dry is not so important, but ventilation to ensure the humidity is not high becomes more important.

The damp and timber treatment industry is for the most part just a large rip-off business. I don't believe there is any magic bullet chemical to protect against dry rot. So any such protection is done with very toxic "kill everything" chemicals, which might not be the sort of thing you want around your home. There have been a number of cases of Trading Standards catching such companies just spraying water in any case, and charging a fortune of course.
If you remove the infected timber and the rhyzomorphs (branches which grow out of the timber in search of new timber to infect and carry the water necesssary to digest the timber away from the water source), and get the humidity and brickwork moisture back down to normal levels, it can't grow. (A blow lamp is good for burning it off walls.)
Dry rot is not native to the UK and cannot live in our normal weather conditions. It only lives in damp micro-climates which are created in damp unventilated areas of homes. It can grow from there to drier areas, carrying the water it needs to grow with it, but there has to be a source of damp somewhere for it to grow. It needs quite specific moisture conditions for a spore to germinate, but once it starts, it can grow over a slightly wider range of humidities and survive without growing over an ever wider range.
Its native habitat are damp caves in the Himalayas where it lives on the tree roots which break in through the cave walls. It was brought back to the UK in the hulls of wooden ships (which it also really liked to infect).
--
Andrew Gabriel


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Yes, it looks like a nest. Certainly not dry rot! This would be within the joist itself, not stuck on the outside like this.
Rob Graham
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Many thanks to you both, vastly relieved. There have been dead wasps appearing in the loft - but I must check and recheck ventilation in that corner anyway - it is next to the water tank, so prone to feel damp.
Lol
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It is deffanitly a small wasp nest. Just remove it, From the size there sould not be any active wasps.
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Yup defiantly a wasps nest.
Had a few in my loft and no matter how many times you remove them or spray the timbers afterwards them seem to come back overnight. The only way is to remove all traces of the nest, if you can, and then spray the timbers around the area with that nice spray foam to try and mask the scent. If they do return then again, from a safe distance, spray the foam over the nest and retreat. Keep doing this over several days to wear them down and kill them all. Pity really because their nests (combs) are really quite artistic and delicate - been made of wood pulp and saliva and are very light to the touch.
Ash.
http://www.localhoney.co.uk/aboutbeespages/wasps.htm
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A word of warning - although this probably doesn't apply in a loft....
We had a wasps' nest in the top corner of the garage last year, so dealt with it from a safe distance with the foam spray stuff.
Lower down, we had a couple of old brass oil-lamps on a shelf. The foam dripped on to these, and they turned horribly green very shortly afterwards. Haven't tried to clean them, as we assume they're ruined (unless anyone has some tips to the contrary...?).
So definitely worth checking for vulnerable "treasures" before squirting...!
--
Martin













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It is a wasp nest, you can leave it there if you like as wasps will not return to an old nest. Trevor Smith
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Sorry Trevor but the wasps will return to the old nest ... they're attracted to the scent of the old nest ... but they wont reuse the old nest as it's too fragile and unhygienic for the new grubs. They'll make a new nest next to the old one. Best to remove and try and mask the scent. If you've had the wasps for a year or two you can usually find old shells of nests close by. Now is an ideal time to give the area a good masking with either the pray foam wasp killer or some nice smelly creosote (if you can stand the smell of the stuff).
Ash.
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I tried Creosote but the wasps totally ignored it. Also be careful about using spray yourself, as dead wasps give off some type of scent which then prompts the other wasps to attack, ok if you have got a full protective suit, but very painful if not.
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You could always play a recording of Gordon "Slack Jaw" Brown's British Job's for British Workers speech ... that'll make the wasps bawk and want to retreat to a safe distance.
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I didn't realize that, I have had an old little nest in my loft for about three years so I better get rid just in case.
Trevor Smith
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If they haven't returned in the 3 years I don't think they'll be returning so you should be ok .... they tend to return each year and if they don't then chances are they've all been killed or made off with some better looking wasp :o)
Ash
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I didn't know this either until about 6 years ago. Having left a couple of nests in our loft the size of the one originally pictured, the next year the little buggers built one the size of a dustbin!!! Now I always spray them when I spot a small one.
Mike
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This site may help to relieve you of worries about dry rot ... if you have anything like this in your house ... RUN
Ash
http://www.marstontimber.co.uk/true_dry_rot_infestation.html
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That site is clearly designed for shock horror impact rather than to be helpful. What would be more useful is a picture of what the very first signs look like.
Its a worry for me, as this is an old house built c. 1895 - has a lot of old timber
Thanks to this group for reassurance - really!
Lol
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The very first signs are hard to see, and I'm not too sure what they look like.
Next you will see what looks like creeper branches growing out from the infected timber, along surfaces in search of new timber to feed on. They can also go through cracks in brickwork and along behind plaster. The infected timber will shrink, crack and crumble, as the dry rot eats the cellulose in the timber (which is what gives timber its strength). This cracking and shrinking is common to most fungal infections though, as they all strip the cellulose out of timber to feed themselves.
Those pictures were the fruiting bodies, but sometimes you don't get those at all.

Dry Rot is not native to the UK, and will not grow in normal conditions of temperature and moisture found here. It comes from the Himalayas, where it lives in damp caves on dead tree roots which break in through the cave walls. It was carried back here in timber boats and probably in some of the goods they carried.
The only way it can grow here is if you manage to create a micro climate somewhere in your building which resembles a Himalayan cave. This will be an area with excess moisture, and a lack of ventilation. Water leaking into an enclosed unventilated building space is the normal cause. It can be a micro area such as where a timber is in contact with damp brickwork, even if the area as a whole doesn't seem damp. So that's the sort of situation you need to avoid, and then it can't establish itself. If it does get established, it can spread into areas which are not so damp, as it can carry the moisture it needs to grow through its branches (hyphae).
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
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Yes it's a wasps nest. We have had two treated. Take care as angry wasps are very aggressive, best to contact your local council who will spray it safely with the right type of powder.This is a good time as they will be not very active.
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