Found elsewhere
Wally
------------------------------------------------------------------------
Today, while fixing a broken floorboard, I discovered rotten wood in a
joist. Since all I know about wood rot is that there are basically
two kinds: "dry rot" and "wet rot", it was time to Google. After
reading a lot of websites on the subject, here is a summary of my
findings.
- Dry rot is caused by the fungus Serpula Lacrymans, whereas wet rot
is caused by the fungus Serpula Lacrymans. The two types of fungus
spread in very different ways. Wet rot is not a fungal infestation.
- "Wet rot" is a misnomer, because it's actually not wet at all. You
can tell if it's wet rot because it's wet, unlike dry rot which is wet
and feels dry to the touch.
- "Dry rot" is also a misnomer, because the wood is not dry, so any
moisture in the wood means it isn't not dry wet rot.
- If your wood has cracks across the grain, it's probably wet rot; dry
rot, on the other hand, has cracks that run *across* the grain.
- If you have dry rot, you need to remove all timber within 1m. You
should also remove all timber within 4m. The minimum distance is 5m,
although 2m is considered the least you can get away with.
- Do *not* attempt to treat dry rot yourself. Call in the qualified
experts, who routinely misdiagnose and do more work than is necessary;
ensure that they don't skimp on the job. You can do the job yourself
with commercially available treatments.
- There is no treatment other than cutting out all the wood within an
average of 2.6667m (mean) 3m (median) and 1m (mode).
- The dry rot fungus is harmless to human beings, so ensure you always
wear a mask.
- Dry rot is so called because it grows in dry areas, using the
plentiful moisture it finds to grow. It then sends out tendrils of up
to 3m or even 2m in length in search of other dry wood from which it
extracts the moisture.
- Wet rot thrives in places where there is little or no ventilation,
such as outside woodwork.
- If you see a joiner poking the tip of a screwdriver into a wooden
window-frame, he is testing for wet rot. Dry rot can be tested for by
poking with the tip of a screwdriver.
- Wood affected by wet rot is crumbly to the touch, whereas wood
affected by dry rot falls apart when you squeeze it. If the affected
wood is darker than the surrounding timber, you have dry rot; wet rot
makes the wood turn a darkish hue.
- Dry rot is common in older buildings, whereas wet rot can occur in
relatively new buildings. However, dry rot and wet rot are found in
old constructions, whereas wet rot and dry rot can affect even
recently-built houses. Wet rot is common in older buildings.
- The best way to deal with both kinds of rot in the long term is by
prevention. Make sure that timber is well-ventilated to prevent dry
rot, and kept dry to prevent wet rot. To keep timber dry, make sure
it is well-ventilated, but beware of water entering through the
ventilation holes.
John D.
at the Leeds College of Art. I spent years studying to achieve my City and
Guilds Full Technological Certificate in Painting and Decorating. Having
achieved this, nobody has ever asked me a question about anything that I
learnt. It seems such a waste! You need the Certificate to get certain jobs.
Now Wally comes to the rescue, (in a way) and I am able to use this superior
knowledge! I'm waiting for someone to ask me what pigment is made from
ferrous sulphate and potassium ferro-cyanide. Of course it's Prussian Blue,
but I'd still like to be asked. I wonder what useless information plumbers
have to learn that nobody asks about? Or teachers, accountants? Perhaps I
shouldn't have had that last pint at the club, I'm getting argumentative!
:-)) John D.
"Wally" <n...@anyprice.com> wrote in message
news:du4uk7$b7s$1...@newsg2.svr.pol.co.uk...
Flyińg Ńuń 2°°6 +
Sounds like a load of *Tommy* rot to me. :)
--
Heard melodies are sweet, but those Unheard melodies are sweeter
flyi...@tiscali.co.uk FN 2같5 +, Mungo Brandybuck of Buckland
Foxy at w**k
Jen
John D.
"Foxy at w**k" <tuckert...@flatroofingcontractors.co.uk> wrote in
message news:du6gga$nf1$1...@newsg1.svr.pol.co.uk...
> Wally wrote:
>> Can you make any sense of it ??? :o))
>> ------------------------------------------------------------------------
>>
>> Today, while fixing a broken floorboard, I discovered rotten wood in a
>> joist. Since all I know about wood rot is that there are basically
>> two kinds: "dry rot" and "wet rot", it was time to Google. After
>> reading a lot of websites on the subject, here is a summary of my
>> findings.
>>
>> - Dry rot is caused by the fungus Serpula Lacrymans, whereas wet rot
>> is caused by the fungus Serpula Lacrymans. The two types of fungus
>> spread in very different ways. Wet rot is not a fungal infestation.
>>
>> - "Wet rot" is a misnomer, because it's actually not wet at all. You
>> can tell if it's wet rot because it's wet, unlike dry rot which is wet
>> and feels dry to the touch.
I must have been drunk last night. It's John Smiths Smooth! 8-) John
D.
mgre...@entomology-mansions.co.uk
> Can you make any sense of it ??? :o))
> ------------------------------------------------------------------------
>
> Today, while fixing a broken floorboard, I discovered rotten wood in a
> joist. Since all I know about wood rot is that there are basically
> two kinds: "dry rot" and "wet rot", it was time to Google. After
> reading a lot of websites on the subject, here is a summary of my
> findings.
>
They are horrible terms, but yes. Dry rot = Serpula lacrymans. Wet rot
= everything else. As I say, horrible terms.
> - Dry rot is caused by the fungus Serpula Lacrymans,
True
> whereas wet rot is caused by the fungus Serpula Lacrymans.
False
> The two types of fungus spread in very different ways.
False
> Wet rot is not a fungal infestation.
False. It is caused by decay fungi of various species.
>
> - "Wet rot" is a misnomer, because it's actually not wet at all. You
> can tell if it's wet rot because it's wet, unlike dry rot which is wet
> and feels dry to the touch.
All total rubbish. The term dry rot comes from a team of scientists
working at Imperial College after the war. The terms these rots dry as,
by the time, they got to see timbers affected by them they were dry,
brown and cuboidally cracked. As the remedial industry grew post-war,
the term 'true dry rot' referring specifically to S. lacrymans came
about.
All fungi need water to grow. All active decay fungi and the damage
caused by them will be wet.
>
> - "Dry rot" is also a misnomer, because the wood is not dry,
True, if it's active.
> so any moisture in the wood means it isn't not dry wet rot.
My word. OK: true, but confusing. The fact there's moisture in the
wood, is not a determining factor. Both dry rot and wet rots require
water.
>
> - If your wood has cracks across the grain, it's probably wet rot; dry
> rot, on the other hand, has cracks that run *across* the grain.
Quick lesson in wood mycology:
Wood decay fungi use two different chemical mechanisms to break down
wood into chemicals the fungus can metabolise: the brown rot and white
rot decay mechanisms.
Brown rots leave wood brown often with cracks across the grain. white
rots leave wood white and stringy (think of decayed external window
sills).
S. lacrymans uses the brown rot decay mechanism. so do a lot of other
(wet) rots.
>
> - If you have dry rot, you need to remove all timber within 1m. You
> should also remove all timber within 4m. The minimum distance is 5m,
> although 2m is considered the least you can get away with.
All rubbish. ATTEND TO THE SOURCE OF WATER. The fungus will then die.
Common sence so far, isn't it. Cut back any decayed timber to sound and
repair as necessary.
>
> - Do *not* attempt to treat dry rot yourself. Call in the qualified
> experts, who routinely misdiagnose and do more work than is necessary;
> ensure that they don't skimp on the job. You can do the job yourself
> with commercially available treatments.
No treatments are necessary other than to ATTEND TO THE SOURCE OF
WATER. The fungus will then die. No point treating something that's
already dead.
>
> - There is no treatment other than cutting out all the wood within an
> average of 2.6667m (mean) 3m (median) and 1m (mode).
>
All rubbish- see above.
> - The dry rot fungus is harmless to human beings, so ensure you always
> wear a mask.
It's harmless unless you breath in a vast amount of spores. at that
point you might get a few respiratory problems, but then that's true of
all fungi that are likely to produce a lot of spores.
>
> - Dry rot is so called because it grows in dry areas,
Ha! Yes, scientists should start using it to recolonise deserts.
Seriously, this is rubbish. It's a fungus. It needs water.
> It then sends out tendrils of up
> to 3m or even 2m in length in search of other dry wood from which it
> extracts the moisture.
Unsuprisingly, it is looking for wet wood, not dry wood.
> - Wet rot thrives in places where there is little or no ventilation,
It can grow there, yes
> such as outside woodwork.
It can grow there too, see the comments about white rot on external
joinery above.
> - If you see a joiner poking the tip of a screwdriver into a wooden
> window-frame, he is testing for wet rot. Dry rot can be tested for by
> poking with the tip of a screwdriver.
Funnily enough, you can test for damage caused by both wet rots and dry
rot with a screwdriver.
> - Wood affected by wet rot is crumbly to the touch, whereas wood
> affected by dry rot falls apart when you squeeze it. If the affected
> wood is darker than the surrounding timber, you have dry rot; wet rot
> makes the wood turn a darkish hue.
Confusingly. See above comments about brown rots. S. lacrymans and
other (wet) rots turn wood brown in the brown rot decay process.
>
> - Dry rot is common in older buildings, whereas wet rot can occur in
> relatively new buildings. However, dry rot and wet rot are found in
> old constructions, whereas wet rot and dry rot can affect even
> recently-built houses. Wet rot is common in older buildings.
Wherever there is wet timber in buildings, they can be found. They have
no architectural preferences.
>
> - The best way to deal with both kinds of rot in the long term is by
> prevention.
Agree with that.
> Make sure that timber is well-ventilated to prevent dry
> rot, and kept dry to prevent wet rot. To keep timber dry, make sure
> it is well-ventilated, but beware of water entering through the
> ventilation holes.
Ventilation is good, yes. Lowers the timber moisture content. Certainly
part of the solution rather than the problem.
And, to cut to the chase: if you have a brown, rotten joist end it is
very likley to be wet rot damage. Cut the joist back to sound timber.
Splice in a replacement section. Wrap the bearing end in a damp-proof
membrane or similar and refit.
Does that help matter a bit?
Matt