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.
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.
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.
PS. I will be fixing both sides of the wall, as (un)fortunately, the cottage
came with the house!
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
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).
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.
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
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...!
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
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.
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)
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.
That site is clearly designed for shock horror impact rather than to be
What would be more useful is a picture of what the very first signs look
Its a worry for me, as this is an old house built c. 1895 - has a lot of old
Thanks to this group for reassurance - really!
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
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).
[email address is not usable -- followup in the newsgroup]
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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