Hi all,

Lots of work at the Bungalow today. All went well, until this, though:

http://photos.dionic.net/v/public/bungalow/mushroom/

Wonder if the phots are enough for someone to be able to cast an opinion on
whether it's dry or wet rot?

These are the timbers underneath a lead flat roof, on the side of the
building (which is otherwise hipped roofed).

Looks more like wet rot to me - but how can I be sure it's not dry rot?

If it's wet rot, then I can replace the visible section of wall plate and
one flat roof rafter (which is separate to the main roof rafters) and one
ceiling joist.

If it's dry rot, then I'm scared... Presumably that means new flat roof
time, due to having to cut back 2-3 feet from the affected areas?


More background:

I didn't see any "cotton wool" nor fruiting bodies. Not sure what the white
staining is, but it's not hairy.

The neighbour told me that the roof used to be felted, and was leaded 10-15
years back - presumably there could have been a serious leak then. It's
generally dry now.

The rafter has rotted completely at the end, and is apparantly all right,
otherwise *except* that the core has rotted for about another 8" (needed to
jab a chisel in to discover that).

The wall plate is totally gone a foot either side, but neighbouring rafters
seem fine. The wall plate has bottom half rot for all the visible parts,
but on the far left, it's petered down to perhaps only 1/8" is dodgey.

Looks like the water got into the inner wall leaf, then rotted the wall
plate from beneath.

The planks supporting the lead seem solid and as you can see, not problems
at all at the other end, where the main hipped roof rafters sit.

Thanks *very* much in advance

Cheers

Tim

AIUI the diamonding pattern in the timber is characteristic of wet rot
and, as you say, the only remedial action required should be to cut
out and replace the affected areas. So long as the source of dampness
has been stopped, ther should be no more problems. Was that an
enclosed roof void with no ventilation?

RubberBiker coughed up some electrons that declared:

AIUI the diamonding pattern in the timber is characteristic of wet rot
and, as you say, the only remedial action required should be to cut
out and replace the affected areas.

Yea! Then I won't worry if the odd millimeter or so of the base of the wall
plate is rotton to the far left then - it would be a right PITA to replace
that bit as it disappears behind various things.

Replacing the bit that disappears off the right side (over the end external
11" wall) will be bad enough, but I think I can wiggle/hack that out once
I've acrow-propped the roof up and relieved the load. There's only one
further rafter beyond the right side and it feels sound to my fingers,
though I can't actually see it.

I'll stick some DPM under the new section of wall plate for good measure.

So long as the source of dampness
has been stopped,

It has - probably 10+ years back.

ther should be no more problems. Was that an
enclosed roof void with no ventilation?

Sort of. It is open to the roof voids in the main house via a 2" gap over
the main wall plate on the inside wall, but not to the outside directly.
This area is going to be a shower room, so I knew I needed to take the
plasterboard off in order to insulate, vapour seal and re-panel with
aqua-panel or similar - otherwise I'd get a ton of moisture going up into
that space.

I'll be adding ventilators into the fascia too (no soffits in that part).

Is it worth sloshing some fungicide around too?

Thanks very much

Cheers

Tim

PS

I should be grateful - despite the house having had some abuse over the
years, this is the first bit of serious rot I've come across, apart from
the soffits - but they always go eventually. I'll be re-doing them in a
couple of years.

On 7 Mar, 22:52, Tim S wrote:
RubberBiker coughed up some electrons that declared:

AIUI the diamonding pattern in the timber is characteristic of wet rot
and, as you say, the only remedial action required should be to cut
out and replace the affected areas.

Yea! Then I won't worry if the odd millimeter or so of the base of the wall
plate is rotton to the far left then - it would be a right PITA to replace
that bit as it disappears behind various things.

Replacing the bit that disappears off the right side (over the end external
11" wall) will be bad enough, but I think I can wiggle/hack that out once
I've acrow-propped the roof up and relieved the load. There's only one
further rafter beyond the right side and it feels sound to my fingers,
though I can't actually see it.

I'll stick some DPM under the new section of wall plate for good measure.

So long as the source of dampness
has been stopped,

It has - probably 10+ years back.

ther should be no more problems. Was that an
enclosed roof void with no ventilation?

Sort of. It is open to the roof voids in the main house via a 2" gap over
the main wall plate on the inside wall, but not to the outside directly.
This area is going to be a shower room, so I knew I needed to take the
plasterboard off in order to insulate, vapour seal and re-panel with
aqua-panel or similar - otherwise I'd get a ton of moisture going up into
that space.

I'll be adding ventilators into the fascia too (no soffits in that part).

Is it worth sloshing some fungicide around too?

Thanks very much

Cheers

Tim

PS

I should be grateful - despite the house having had some abuse over the
years, this is the first bit of serious rot I've come across, apart from
the soffits - but they always go eventually. I'll be re-doing them in a
couple of years.

Tim
AFAIK the characteristic of dry rot is that the mycellium will grow
out from the initial place of infection to seek moisture. If there is
a centre here - the rotted area - I would have expected dry rot in the
intervening 10 years to have spread out from that seeking moisture and
rotting the timbers in the process. The other factor is that dry rot
requires a degree of warmth hence the problem with adding CH to old
buildings - if this roof space is dry and 'cold' then any DR spores
won't have had an opportunity to develop.

One of the best examples of DR I've seen was in an old building that
had wooden warm air ducts for it's CH - it also had a cavity
constructed wall with heather insulation. Sadly there was a water
pipe leak and DR developed in the ducting where the fruiting bodies
were large - was transmitted round the building and got into the
cavity insulation. I think in the end the building was flattened.

Anyhow I would, as you suggest, slosh some suitable anti-fungal stuff
around.

All the best and I well understand your worries.
Rob

Rob G coughed up some electrons that declared:


Tim
AFAIK the characteristic of dry rot is that the mycellium will grow
out from the initial place of infection to seek moisture. If there is
a centre here - the rotted area - I would have expected dry rot in the
intervening 10 years to have spread out from that seeking moisture and
rotting the timbers in the process. The other factor is that dry rot
requires a degree of warmth hence the problem with adding CH to old
buildings - if this roof space is dry and 'cold' then any DR spores
won't have had an opportunity to develop.

That's very interesting - didn't know about dry rot not liking cold.
Regarding the 10 years - I would have expected serious devastation too, from
dry rot in that time, which gave me hope.


One of the best examples of DR I've seen was in an old building that
had wooden warm air ducts for it's CH - it also had a cavity
constructed wall with heather insulation. Sadly there was a water
pipe leak and DR developed in the ducting where the fruiting bodies
were large - was transmitted round the building and got into the
cavity insulation. I think in the end the building was flattened.

Anyhow I would, as you suggest, slosh some suitable anti-fungal stuff
around.

All the best and I well understand your worries.

The only time I've actually seen dry rot, was in a window frame and
surrounding wall when I was a lad, so only vague memories...

Thanks

Tim

Tim S wrote:

Lots of work at the Bungalow today. All went well, until this, though:

http://photos.dionic.net/v/public/bungalow/mushroom/

Wonder if the phots are enough for someone to be able to cast an opinion on
whether it's dry or wet rot?

These are the timbers underneath a lead flat roof, on the side of the
building (which is otherwise hipped roofed).

Looks more like wet rot to me - but how can I be sure it's not dry rot?

Yup I would agree - almost certainly not dry rot. None of the tell tales
like (fruiting bodies etc), no filaments with dripping water, and none
of the typical crazing/shrinkage visible where the wood shrinks and
cracks like a dry river bed as the cellulose gets digested.

If it's wet rot, then I can replace the visible section of wall plate and
one flat roof rafter (which is separate to the main roof rafters) and one
ceiling joist.

As long as you make sure no new water can get it, then that should fix it.

If it's dry rot, then I'm scared... Presumably that means new flat roof
time, due to having to cut back 2-3 feet from the affected areas?

Its not as scary as people make out... The main requirement is to cut
off the source of water. Ventilation helps as well. Cut away anything
obviously rotten and a bit beyond (2 - 3 feet is probably excessive),
spray everythign in the are with a decent dry rot treatment.

Looks like the water got into the inner wall leaf, then rotted the wall
plate from beneath.

Quite possible.

Found something similar in the under stairs cupboard here. 9" solid wall
with waterproof render over and no ventilation at the far end of the
cupboard (about 12' deep!) resulted in condensation on the wall. Since
the wall was impermeable, this just ran down behind the skirting and
into the floor, when it then tracked along the under side of the floor
boards until it hit the joist. It rotted a joist (which was also placed
parallel and too close to the outside wall), plus the end of another
couple that met it on sleeper walls.

My fix was to foam 50mm of celotex to the inside of the wall, replace
the dodgy bits of joist, and fit another 9 air bricks to help ventilate
the (substantial) under floor void - see if we can dry out the damp bits)

The planks supporting the lead seem solid and as you can see, not problems
at all at the other end, where the main hipped roof rafters sit.

Thanks *very* much in advance

In the words of the HHGTTG, Don't Panic!


--
Cheers,

John.

/================================================== ===============\
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| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Rob G wrote:

AFAIK the characteristic of dry rot is that the mycellium will grow
out from the initial place of infection to seek moisture. If there is

I thought they grew out from a wet place to seek new timber - conducting
the moisture with them to otherwise dry timber (hence the name)?

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

"Tim S" wrote in message
...
Hi all,

Lots of work at the Bungalow today. All went well, until this,
though:

http://photos.dionic.net/v/public/bungalow/mushroom/

Wonder if the phots are enough for someone to be able to cast an
opinion on
whether it's dry or wet rot?

These are the timbers underneath a lead flat roof, on the side of
the
building (which is otherwise hipped roofed).

Looks more like wet rot to me - but how can I be sure it's not dry
rot?

If it's wet rot, then I can replace the visible section of wall
plate and
one flat roof rafter (which is separate to the main roof rafters)
and one
ceiling joist.

If it's dry rot, then I'm scared... Presumably that means new flat
roof
time, due to having to cut back 2-3 feet from the affected areas?


More background:

I didn't see any "cotton wool" nor fruiting bodies. Not sure what
the white
staining is, but it's not hairy.

The neighbour told me that the roof used to be felted, and was
leaded 10-15
years back - presumably there could have been a serious leak then.
It's
generally dry now.

The rafter has rotted completely at the end, and is apparantly all
right,
otherwise *except* that the core has rotted for about another 8"
(needed to
jab a chisel in to discover that).

The wall plate is totally gone a foot either side, but neighbouring
rafters
seem fine. The wall plate has bottom half rot for all the visible
parts,
but on the far left, it's petered down to perhaps only 1/8" is
dodgey.

Looks like the water got into the inner wall leaf, then rotted the
wall
plate from beneath.

The planks supporting the lead seem solid and as you can see, not
problems
at all at the other end, where the main hipped roof rafters sit.

Thanks *very* much in advance

Cheers

Tim

That looks identical to the dry rot fungus I had in my last house
before Rentokil replaced timbers and sprayed. Surpula lacrymans iirc
but it was 25 years ago!

AWEM

Andrew Mawson coughed up some electrons that declared:


That looks identical to the dry rot fungus I had in my last house
before Rentokil replaced timbers and sprayed. Surpula lacrymans iirc
but it was 25 years ago!

Oh - the concensus is no longer 100%.

Tim S wrote:
Andrew Mawson coughed up some electrons that declared:


That looks identical to the dry rot fungus I had in my last house
before Rentokil replaced timbers and sprayed. Surpula lacrymans iirc
but it was 25 years ago!

Oh - the concensus is no longer 100%.


well it hardly matters which it is, since both need damp to flourish and
both need entirely removing, and remedial action to remove the wetness
applied, as well a replacement of structurally deficient timbers.

A good fungicide is also a good idea as well.

The Natural Philosopher coughed up some electrons that declared:


well it hardly matters which it is, since both need damp to flourish and
both need entirely removing, and remedial action to remove the wetness
applied, as well a replacement of structurally deficient timbers.

A good fungicide is also a good idea as well.

So would it matter if a section of generally sound, but inaccessible timber
with a trace of rot is left in place (the alternative being to strip the
roof, which is lead)?

For wet rot, I would say yes.

For dry rot, I'm still a bit contaminated by the 70's notion that one hint
of dry rot left will eat your house alive.

Where did that idea come from? Was it scaremongering by rot-killing firms?

Cheers
Tim

Tim S wrote:
The Natural Philosopher coughed up some electrons that declared:


well it hardly matters which it is, since both need damp to flourish and
both need entirely removing, and remedial action to remove the wetness
applied, as well a replacement of structurally deficient timbers.

A good fungicide is also a good idea as well.

So would it matter if a section of generally sound, but inaccessible timber
with a trace of rot is left in place (the alternative being to strip the
roof, which is lead)?

For wet rot, I would say yes.

For dry rot, I'm still a bit contaminated by the 70's notion that one hint
of dry rot left will eat your house alive.

Where did that idea come from? Was it scaremongering by rot-killing firms?

Cheers
Tim

If theres no water getting to the wood, it isnt going to rot any more.
That simple.

If you realy want to know which it is, this should clear it up:
http://www.wiki.diyfaq.org.uk/index.php?title=Wood_Rot


NT

coughed up some electrons that declared:



If theres no water getting to the wood, it isnt going to rot any more.
That simple.

OK - I'm happy to believe that now, but old habits die hard - hope you
understand!

If you realy want to know which it is, this should clear it up:
http://www.wiki.diyfaq.org.uk/index.php?title=Wood_Rot

Wibble.... That about summed up my conclusion after googling, before I
posted the start of this thread!

In article ,
writes:

If you realy want to know which it is, this should clear it up:
http://www.wiki.diyfaq.org.uk/index.php?title=Wood_Rot

I presume that's meant to be a joke?

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Andrew Gabriel wrote:

In article ,
writes:
If you realy want to know which it is, this should clear it up:
http://www.wiki.diyfaq.org.uk/index.php?title=Wood_Rot

I presume that's meant to be a joke?

http://newsgroups.derkeiler.com/Arch.../msg00009.html

Andrew Gabriel coughed up some electrons that declared:

In article
,
writes:

If you realy want to know which it is, this should clear it up:
http://www.wiki.diyfaq.org.uk/index.php?title=Wood_Rot

I presume that's meant to be a joke?



I took it to be, after the first couple of sentences. Sadly, it *is* an
accurate reflection on the results of earnest research into the subject on
google. There seems to be very little deliberate effort at parody and a
great deal of ******** on the web.

The problem with something like this is the FUD factor - *if* dry rot can
consume your house, even after the initial water ingress is cured (by
supposedly generating its own water as a by product of eating the wood),
then you scare people into expensive work just to get a 10 year guarantee.

OTOH, if that were true, given my roof has been dry for 10+ years, then it
should have continued to eat at least the entire rafter, not stopped after
about 8".

My concern is that once this ceiling is put back, there's no easy way to
monitor the situation, which amplifies the risk of getting it wrong.

But I'll go with the general opinion that the sodding mushrooms are
dead/inactive, and I'll just replace structurally deficient timber as is
practical, lob some fungicide in because it's cheap and why not, and
reconstruct things so that damp can never form there again.

Sound reasonable?

Cheers

Tim

Tim S wrote:
Andrew Gabriel coughed up some electrons that declared:

In article
,
writes:

If you realy want to know which it is, this should clear it up:
http://www.wiki.diyfaq.org.uk/index.php?title=Wood_Rot

I presume that's meant to be a joke?



I took it to be, after the first couple of sentences. Sadly, it *is* an
accurate reflection on the results of earnest research into the subject on
google. There seems to be very little deliberate effort at parody and a
great deal of ******** on the web.

The problem with something like this is the FUD factor - *if* dry rot can
consume your house, even after the initial water ingress is cured (by
supposedly generating its own water as a by product of eating the wood),
then you scare people into expensive work just to get a 10 year guarantee.

OTOH, if that were true, given my roof has been dry for 10+ years, then it
should have continued to eat at least the entire rafter, not stopped after
about 8".

My concern is that once this ceiling is put back, there's no easy way to
monitor the situation, which amplifies the risk of getting it wrong.

But I'll go with the general opinion that the sodding mushrooms are
dead/inactive, and I'll just replace structurally deficient timber as is
practical, lob some fungicide in because it's cheap and why not, and
reconstruct things so that damp can never form there again.

Sound reasonable?

Cheers

Tim

Perfectly. I also note that on roofs like that, even if one joist
fails completely the result isnt anything serious, just a little minor
local sag, hence some folk wouldn't do anything about it.

Rot fungi are like any other fungal plant, they need water to survive.
Without that, they're going nowhere.


NT

In article ,
Tim S writes:
Andrew Gabriel coughed up some electrons that declared:

In article
,
writes:

If you realy want to know which it is, this should clear it up:
http://www.wiki.diyfaq.org.uk/index.php?title=Wood_Rot

I presume that's meant to be a joke?

I took it to be, after the first couple of sentences. Sadly, it *is* an
accurate reflection on the results of earnest research into the subject on
google. There seems to be very little deliberate effort at parody and a
great deal of ******** on the web.

I've written a few articles about dry rot if you search on Google.
I agreed with the comments others already made that this doesn't
look like dry rot from what I can see in the pictures. However,
it's perfectly possible to have dry rot with no fruiting bodies,
and it's possible you can't see the mycellium, so it's impossible
to completely rule it out. The pictures aren't easy to examine in
detail. The location looks perfect for dry rot though.

The problem with something like this is the FUD factor - *if* dry rot can
consume your house, even after the initial water ingress is cured (by
supposedly generating its own water as a by product of eating the wood),
then you scare people into expensive work just to get a 10 year guarantee.

It needs a source of moisture (doesn't need to be visible water,
a damp wall will do). It will carry the water from one site to
another, in order to infect timber which wouldn't otherwise be
susceptable, hence its ability to infect dry timber, unlike wet
rot. If the water source is cut off, it will stop growing. There
could still be enough moisture leaking in from the house to stop
it from completely dying though.

OTOH, if that were true, given my roof has been dry for 10+ years, then it
should have continued to eat at least the entire rafter, not stopped after
about 8".

It's not true.

My concern is that once this ceiling is put back, there's no easy way to
monitor the situation, which amplifies the risk of getting it wrong.

Keeping water out, and ventilation are the important things.
Secondly, you can try protecting new timber against contact with
walls. Nowadays, joist hangers are often used which are much better
in this respect. The other technique is to wrap the joist ends which
are in close contact with walls (although the wrapping could be bad
if you end up with water streaming in, by keeping it in the timber).

But I'll go with the general opinion that the sodding mushrooms are

I couldn't make out any mushrooms in the pics. Were there some?

dead/inactive, and I'll just replace structurally deficient timber as is
practical, lob some fungicide in because it's cheap and why not, and
reconstruct things so that damp can never form there again.

You won't be able to get any fungicide nowadays which will protect
against anything, and there never was one which was particularly
effective against dry rot (it's one of the most resistant fungi).
The only protection was to make the whole area toxic with heavy
metals, but that's no longer allowed.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Tim S wrote:
The Natural Philosopher coughed up some electrons that declared:


well it hardly matters which it is, since both need damp to flourish and
both need entirely removing, and remedial action to remove the wetness
applied, as well a replacement of structurally deficient timbers.

A good fungicide is also a good idea as well.

So would it matter if a section of generally sound, but inaccessible timber
with a trace of rot is left in place (the alternative being to strip the
roof, which is lead)?

For wet rot, I would say yes.

For dry rot, I'm still a bit contaminated by the 70's notion that one hint
of dry rot left will eat your house alive.

Where did that idea come from? Was it scaremongering by rot-killing firms?

Cheers
Tim

If you mange to halt the fungus growth and th wood is adequately sound,
thats all that matters.

The Natural Philosopher coughed up some electrons that declared:

If you mange to halt the fungus growth and th wood is adequately sound,
thats all that matters.

Thanks for the re-assurance

I'll order the wood. As the room's a shower area, I'll make sure the ceiling
is totally vapour proof (that's why I pulled the plasterboard off in the
first place!).

Cheers

Tim

Judging by the second picture it is dry rot.
You don't always get a fruiting body - I've seen plenty of rampant dry
rot and not a mushroom in sight.
You do often get the stringy white rhizomes - particularly visible
when you cut out the infected wood - it runs along between the brick
and the wood.
by law you are meant to cut out all timber 1metre beyond the any
evidence of the dry rot and replace.
The adjoining walls should be treated and treated timbers used in the
repair.
You can be held responsible if at a later stage your dry rot invades a
neighbour's property so it is especially important to properly deal
with any dry rot on or near a party wall.
dry rot spores lie dormant for many years/decades waiting for the
right conditions ie 40% moisture or above

Tim S wrote:

Hi all,

Lots of work at the Bungalow today. All went well, until this, though:

http://photos.dionic.net/v/public/bungalow/mushroom/

Wonder if the phots are enough for someone to be able to cast an opinion on
whether it's dry or wet rot?

These are the timbers underneath a lead flat roof, on the side of the
building (which is otherwise hipped roofed).

Looks more like wet rot to me - but how can I be sure it's not dry rot?

If it's wet rot, then I can replace the visible section of wall plate and
one flat roof rafter (which is separate to the main roof rafters) and one
ceiling joist.

If it's dry rot, then I'm scared... Presumably that means new flat roof
time, due to having to cut back 2-3 feet from the affected areas?


More background:

I didn't see any "cotton wool" nor fruiting bodies. Not sure what the white
staining is, but it's not hairy.

The neighbour told me that the roof used to be felted, and was leaded 10-15
years back - presumably there could have been a serious leak then. It's
generally dry now.

The rafter has rotted completely at the end, and is apparantly all right,
otherwise *except* that the core has rotted for about another 8" (needed to
jab a chisel in to discover that).

The wall plate is totally gone a foot either side, but neighbouring rafters
seem fine. The wall plate has bottom half rot for all the visible parts,
but on the far left, it's petered down to perhaps only 1/8" is dodgey.

Looks like the water got into the inner wall leaf, then rotted the wall
plate from beneath.

The planks supporting the lead seem solid and as you can see, not problems
at all at the other end, where the main hipped roof rafters sit.

Thanks *very* much in advance

Cheers

Tim

Having suffered wet and dry, I'd vote for the wet.
Common factor in the dry rot I've come acoss, is that the infected
wood looks warped/anorexic in all axes and runs some distance from the
starting point. The pics show rotted wood but still holding it's
initial shape.

On 7 Mar, 22:34, RubberBiker wrote:
AIUI the diamonding pattern in the timber is characteristic of wet rot
and, as you say, the only remedial action required should be to cut
out and replace the affected areas. So long as the source of dampness
has been stopped, ther should be no more problems. Was that an
enclosed roof void with no ventilation?

Dear Tim
The fungus is unquestionably a brown rot but as dry rot is also a
brown rot that does not help!
The photographs have most of the characteristics of wet rot and none
of dry rot. The white part looks to me like a sporophore of C. puteana
(one of the wet rots).
The reasons for my opinion a
a superficial hard outer skin about 0.5 to 1.0 mm thick
the absence of obvious hypal strands
the absence of visible mycelial strands
the confined location
the characteristics of the location (in a roof timber without the
necessary lime mortar for dry rot)
the history of past leaks

To answer and dispel some of the comments and assertions made by
others
Serpula (with an "e") lacrymans has no requirement for a high
temperature and most strains have their optimum at 26 C and are
controlled/killed only a few degrees above that - hence the lack of it
in the outside timbers of south facing windows
Coniophora - cerebella/puteana actually has a higher optimum growth
temperature

You only have to remove unsound timber if the timber cannot fulfil its
structural role
I concur with the opinion that if there is a bit of rot and it is not
fulfilling any structural role it can be left in
It is good sensible practice to isolate from timber with a dpc and
essential to instal ventiation and cross flow of air with cross
battening if you can

Use a thin long drill bit to check for hidden decay in any rafters
timbers about which you are concerned

Use only Tanalised replacements and dip treat overnight any cut end
grain
Put the tanalised end near the brick and the on-site treated end in
the room

It is not worth "sloshing" any fungicide arouond - complete waste of
money and not reasonable in a coshh assessement. Immersion of cut ends
is the only effective use needed

Strands are for the purpose of conduction of nutrients from the hyphal
front not water to it. The strands are thought to have evolved to
reduce water loss in this process. Water at the hyphal front is
abstracted from the atmosphere not along strands
This was published in 1981 by DH Jennings at the University of
Liverpool using C 14 glucose to follow the nutrients - mostly in
trehalose. The conclusion was that one needed 95% RH for DR to
flourish.


Meow2 is correct but that does not fix your structural problem or
prevent recurrence if there is a new leak

Dry rot can only continue to "eat your house" (after the water source
has been fixed) if the interstices are at an RH of greater than 95%
and that only happens when the masonry is very wet and acts as a
reservoir. it also has to be alkaline as cement mortar does not suppor
the dry rot. This is not common so most dry rot dies when the water
source is fixed. That is most - not all!!!
If, however, you have active dehumidifiction you will cure it and
after a year at normal ~RT it will die

I do not agree with Andrew G that the location is perfect for dry rot
for the reasons cited above and specifically absence of lime mortar in
the roof where the sporophore/mycelium is and the absence mortar to
act as a reservoir

It does not carry water from one site to the other - read the Jennings
paper.

There are plenty of fungicides available - how about boron for a kick
off - but I agree that non is needed for sloshing. All on the market
have passed efficacy tests or they would not get the licence!

I shall be interested to know which Parliamentary Act requires one to
cut out a metre beyond as I have served on various committees such as
the BWP(D)A / HSE consulation group prior to the introcuction of COSHH
in the late 70s and am familiar with COPR, BRE digest 299 and BRs and
have been working both academically (my thesis was at ICST on
hemicellulose degradation by fungi) and practically since the late 60s
and am unaware of such a law. Indeed I have spent most of the last 35
years promoting the complete opposite and opposing the con-men who
propose such rubbish

Chris

coughed up some electrons that declared:

Hi Chris,

The fungus is unquestionably a brown rot but as dry rot is also a
brown rot that does not help!
The photographs have most of the characteristics of wet rot and none
of dry rot. The white part looks to me like a sporophore of C. puteana
(one of the wet rots).

OK

The reasons for my opinion a
a superficial hard outer skin about 0.5 to 1.0 mm thick

Check. That was what I found for the next 8" or so beyond the totally gone
bit. Looked OK, but poking a chisel in showed the core to be rotted.

the absence of obvious hypal strands
the absence of visible mycelial strands
the confined location
the characteristics of the location (in a roof timber without the
necessary lime mortar for dry rot)
the history of past leaks

OK.


To answer and dispel some of the comments and assertions made by
others
Serpula (with an "e") lacrymans has no requirement for a high
temperature and most strains have their optimum at 26 C and are
controlled/killed only a few degrees above that - hence the lack of it
in the outside timbers of south facing windows

This is a north facing roof. Interestingly, I've measured 38C in the roof
voids on the southern facing side, during the height of summer.

Coniophora - cerebella/puteana actually has a higher optimum growth
temperature

You only have to remove unsound timber if the timber cannot fulfil its
structural role
I concur with the opinion that if there is a bit of rot and it is not
fulfilling any structural role it can be left in

Whew! As I said, the mostly good bit on the far left would be a sod to
remove as it goes behind a wall.


It is good sensible practice to isolate from timber with a dpc and
essential to instal ventiation and cross flow of air with cross
battening if you can

Yes - I was going to put the new section of plate on a DPC. I'll be sure to
put plenty of ventilation in the fascia - the wind will be able to blow up
into the main roof from this flat roof, and ultimately out some other
vents.

Use a thin long drill bit to check for hidden decay in any rafters
timbers about which you are concerned

Good idea.

Use only Tanalised replacements and dip treat overnight any cut end
grain
Put the tanalised end near the brick and the on-site treated end in
the room

OK

It is not worth "sloshing" any fungicide arouond - complete waste of
money and not reasonable in a coshh assessement. Immersion of cut ends
is the only effective use needed

Strands are for the purpose of conduction of nutrients from the hyphal
front not water to it. The strands are thought to have evolved to
reduce water loss in this process. Water at the hyphal front is
abstracted from the atmosphere not along strands
This was published in 1981 by DH Jennings at the University of
Liverpool using C 14 glucose to follow the nutrients - mostly in
trehalose. The conclusion was that one needed 95% RH for DR to
flourish.

Ah. So prior to then, a lot of misbelief was floating around.


Meow2 is correct but that does not fix your structural problem or
prevent recurrence if there is a new leak

Dry rot can only continue to "eat your house" (after the water source
has been fixed) if the interstices are at an RH of greater than 95%
and that only happens when the masonry is very wet and acts as a
reservoir. it also has to be alkaline as cement mortar does not suppor
the dry rot. This is not common so most dry rot dies when the water
source is fixed. That is most - not all!!!
If, however, you have active dehumidifiction you will cure it and
after a year at normal ~RT it will die

I do not agree with Andrew G that the location is perfect for dry rot
for the reasons cited above and specifically absence of lime mortar in
the roof where the sporophore/mycelium is and the absence mortar to
act as a reservoir

It does not carry water from one site to the other - read the Jennings
paper.

There are plenty of fungicides available - how about boron for a kick
off - but I agree that non is needed for sloshing. All on the market
have passed efficacy tests or they would not get the licence!

OK

I shall be interested to know which Parliamentary Act requires one to
cut out a metre beyond as I have served on various committees such as
the BWP(D)A / HSE consulation group prior to the introcuction of COSHH
in the late 70s and am familiar with COPR, BRE digest 299 and BRs and
have been working both academically (my thesis was at ICST on
hemicellulose degradation by fungi) and practically since the late 60s
and am unaware of such a law. Indeed I have spent most of the last 35
years promoting the complete opposite and opposing the con-men who
propose such rubbish

I've heard everything from a foot to 3 feet - mostly I assumed from
companies offering remedial work!

Many thanks indeed for such an informed reply.

This sure could form a good Wiki entry

Cheers

Tim

wrote:

Strands are for the purpose of conduction of nutrients from the hyphal
front not water to it. The strands are thought to have evolved to
reduce water loss in this process. Water at the hyphal front is
abstracted from the atmosphere not along strands
This was published in 1981 by DH Jennings at the University of
Liverpool using C 14 glucose to follow the nutrients - mostly in
trehalose. The conclusion was that one needed 95% RH for DR to
flourish.

Ah, not heard that before... I appreciated that they strands were taking
nutrients back, but had also read (presumably incorrectly) that they
also carried water to the front (which I presume is also needed for the
digestion of the timber's cellulose by the fungus).

Dry rot can only continue to "eat your house" (after the water source
has been fixed) if the interstices are at an RH of greater than 95%
and that only happens when the masonry is very wet and acts as a
reservoir. it also has to be alkaline as cement mortar does not suppor
the dry rot. This is not common so most dry rot dies when the water
source is fixed. That is most - not all!!!

What would you say to the oft repeated advice that plaster should be
replaced with cement based render? Quite often you see this done on
solid walls with lime mortar. It would seem that this will make the
process of the wall drying even slower?

If, however, you have active dehumidifiction you will cure it and
after a year at normal ~RT it will die

What is the best way to apply the dehumidification - i.e. just running
an ordinary room dehumidifier in the vicinity while keeping the side
exposed, or are there other ways?



--
Cheers,

John.

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\================================================= ================/

Tim S wrote:

Many thanks indeed for such an informed reply.

This sure could form a good Wiki entry

Well volunteered that man ;-)

(got a feeling we did actually discuss that in the past - but never got
round to doing anything. The current one does seem to get mistaken for a
serious article from time to time even though it is in the Humour
category)

--
Cheers,

John.

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| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

wrote in message
...
On 7 Mar, 22:34, RubberBiker wrote:
AIUI the diamonding pattern in the timber is characteristic of wet rot
and, as you say, the only remedial action required should be to cut
out and replace the affected areas. So long as the source of dampness
has been stopped, ther should be no more problems. Was that an
enclosed roof void with no ventilation?

Dear Tim
The fungus is unquestionably a brown rot but as dry rot is also a
brown rot that does not help!
The photographs have most of the characteristics of wet rot and none
of dry rot. The white part looks to me like a sporophore of C. puteana
(one of the wet rots).
The reasons for my opinion a
a superficial hard outer skin about 0.5 to 1.0 mm thick
the absence of obvious hypal strands
the absence of visible mycelial strands
the confined location

It was fine up to here

the characteristics of the location (in a roof timber without the
necessary lime mortar for dry rot)

But that's rubbish, the presence of lime mortar or not
has no relevance as to whether Dry Rot could form in the above case.

-

Mark wrote:
wrote in message
...
On 7 Mar, 22:34, RubberBiker wrote:
AIUI the diamonding pattern in the timber is characteristic of wet rot
and, as you say, the only remedial action required should be to cut
out and replace the affected areas. So long as the source of dampness
has been stopped, ther should be no more problems. Was that an
enclosed roof void with no ventilation?
Dear Tim
The fungus is unquestionably a brown rot but as dry rot is also a
brown rot that does not help!
The photographs have most of the characteristics of wet rot and none
of dry rot. The white part looks to me like a sporophore of C. puteana
(one of the wet rots).
The reasons for my opinion a
a superficial hard outer skin about 0.5 to 1.0 mm thick
the absence of obvious hypal strands
the absence of visible mycelial strands
the confined location

It was fine up to here

the characteristics of the location (in a roof timber without the
necessary lime mortar for dry rot)

But that's rubbish, the presence of lime mortar or not
has no relevance as to whether Dry Rot could form in the above case.

I don't think you can dismiss the effect that easily - cement based
mortars are far less likely to transmit moisture. As evidenced by the
number of soft brick walls that spall the first time there is a frost
after being repointed with an inappropriate cement based mortar (because
the bricks get saturated and can't shift the water into the mortar as
easily as they once did).

So a lime mortar will be more likely to admit moisture, even before you
get onto the effects of its pH.


--
Cheers,

John.

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\================================================= ================/

"Mark" wrote in message
...

wrote in message

...
On 7 Mar, 22:34, RubberBiker wrote:
AIUI the diamonding pattern in the timber is characteristic of
wet rot
and, as you say, the only remedial action required should be to
cut
out and replace the affected areas. So long as the source of
dampness
has been stopped, ther should be no more problems. Was that an
enclosed roof void with no ventilation?

Dear Tim
The fungus is unquestionably a brown rot but as dry rot is also a
brown rot that does not help!
The photographs have most of the characteristics of wet rot and
none
of dry rot. The white part looks to me like a sporophore of C.
puteana
(one of the wet rots).
The reasons for my opinion a
a superficial hard outer skin about 0.5 to 1.0 mm thick
the absence of obvious hypal strands
the absence of visible mycelial strands
the confined location

It was fine up to here

the characteristics of the location (in a roof timber without the
necessary lime mortar for dry rot)

But that's rubbish, the presence of lime mortar or not
has no relevance as to whether Dry Rot could form in the above
case.

-



Except indirectly - lime mortar tends to imply an older building which
may not have the advantage of modern understandings of the need for
sub floor or roof ventilation hence more suceptable to dry rot if
moisture makes its way into the structure, which the very age of the
building increases the likelyhood.

AWEM

John Rumm wrote in message
et...

But that's rubbish, the presence of lime mortar or not
has no relevance as to whether Dry Rot could form in the above case.

I don't think you can dismiss the effect that easily -

" without the _necessary_ lime mortar for dry rot)"

was the quote, Yes its more likely No its not a necessary ingredient, so
anyone reading this thinking oh its ok I haven't got Lime mortar so I cant
have Dry Rot.

-

ScrewMaster wrote:
Judging by the second picture it is dry rot.
You don't always get a fruiting body - I've seen plenty of rampant dry
rot and not a mushroom in sight.
You do often get the stringy white rhizomes - particularly visible
when you cut out the infected wood - it runs along between the brick
and the wood.
by law you are meant to cut out all timber 1metre beyond the any
evidence of the dry rot and replace.
The adjoining walls should be treated and treated timbers used in the
repair.
You can be held responsible if at a later stage your dry rot invades a
neighbour's property so it is especially important to properly deal
with any dry rot on or near a party wall.
dry rot spores lie dormant for many years/decades waiting for the
right conditions ie 40% moisture or above

Why do you judge it to be dry rot?

Dry rot isn't rampant, it spreads according to food source and moisture
content. A maximum is generally regarded to be 1m per year and even then
only under ideal conditions. Above 40% moisture??? More like above 22% and
it'll grow!!

While it's been suggested dry rot spreads more quickly in warm conditions,
it must be remembered that warm ventilated conditions imply dry wood where
dry rot cannot grow!

Dry rot spores tend to last 3 years, longer in cold conditions, shorter in
warm.

One charcteristic of dry rot is a brown dust. A very wet cotton wool like
structure and shrunken and dry looking cracked timber. These pictures show
wet rot!

If you've removed all signs of dry rot, it's unlikely you'd be responsible
for any further damage though it would be reasonable to inform your
neighbour so he can inspect his own timber. Dry rot tends to inflict
volumes with no access!

Remember dry rot needs mosture. As long as wood is in a ventilated area it
will not support dry rot. Moisture content is key.

"Andrew Mawson" wrote in message
...

"Mark" wrote in message

The reasons for my opinion a
a superficial hard outer skin about 0.5 to 1.0 mm thick
the absence of obvious hypal strands
the absence of visible mycelial strands
the confined location

It was fine up to here

the characteristics of the location (in a roof timber without the
necessary lime mortar for dry rot)

But that's rubbish, the presence of lime mortar or not
has no relevance as to whether Dry Rot could form in the above
case.




Except indirectly - lime mortar tends to imply an older building which
may not have the advantage of modern understandings of the need for
sub floor or roof ventilation hence more suceptable to dry rot if
moisture makes its way into the structure, which the very age of the
building increases the likelyhood.


No lime mortar or render is completely irrelevant to an infestation of dry
rot, it can if conditions are suitable aid the spread to other adjacent
timbers that would not initially been able to support the Fungi spoor
germinating.

Serpula lacrymans is a naturally occurring woodland Fungi it survives well
enough outdoors so ventilation alone is clearly not sufficient to stop it's
occurrence, but the inside of a house can if the timber is able to support
germination act as a wonderful petri dish regardless of age.



-

On 9 Mar, 20:57, John Rumm wrote:
wrote:
Strands are for the purpose of conduction of nutrients from the hyphal
front not water to it. The strands are thought to have evolved to
reduce water loss in this process. Water at the hyphal front is
abstracted from the atmosphere not along strands
This was published in 1981 *by DH Jennings at the University of
Liverpool using C 14 glucose to follow the nutrients - mostly in
trehalose. The conclusion was that one needed 95% RH for DR to
flourish.

Ah, not heard that before... I appreciated that they strands were taking
nutrients back, but had also read (presumably incorrectly) that they
also carried water to the front (which I presume is also needed for the
digestion of the timber's cellulose by the fungus).

Dry rot can only continue to "eat your house" (after the water source
has been fixed) if the interstices are at an RH of greater than 95%
and that only happens when the masonry is very wet and acts as a
reservoir. it also has to be alkaline as cement mortar does not suppor
the dry rot. This is not common so most dry rot dies when the water
source is fixed. That is most *- not all!!!

What would you say to the oft repeated advice that plaster should be
replaced with cement based render? Quite often you see this done on
solid walls with lime mortar. It would seem that this will make the
process of the wall drying even slower?

If, however, you have active dehumidifiction you will cure it and
after a year at *normal ~RT it will die

What is the best way to apply the dehumidification - i.e. just running
an ordinary room dehumidifier in the vicinity while keeping the side
exposed, or are there other ways?

--
Cheers,

John.

/================================================== ===============\
| * * * * *Internode Ltd - *http://www.internode.co.uk* * * * * *|
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\================================================= ================/

Dear John

Answers to your two questions
What is the best way to apply the dehumidification - i.e. just running
an ordinary room dehumidifier in the vicinity while keeping the side
exposed, or are there other ways?

Isolate the rooms or areas from any other water sources by shutting
doors and windows and sealing any porous walls such as internal stud
walls by lining with polythene or the like and draught stripping
provide dry heat
install dehumidifer

It is often practical in buildings in the summer simply to open all
the windows in the day and get solar gain and dehumify at night
In the winter just do it all the time!

What would you say to the oft repeated advice that plaster should be
replaced with cement based render? Quite often you see this done on
solid walls with lime mortar. It would seem that this will make the
process of the wall drying even slower?


We never recommend removal of plaster unless it is covering up timbers
that are damp or at risk
Plaster removal is often overdone particularly in listed buildings
where I go to great lenghts not to take it off if possible

If lime plaster is removed there is a cogent argument to put back
lime
I only use cement within 1 m of the ground when there is a history of
hygroscopic salts contaminating due to years of rising damp or when
the building is so modern that it matters not if you use cement

Cement will slow down the drying of the walls but equally it will
provide an instant dry surface for putting on joinery timbers at risk
such a skirtings or architraves and the water in the brick cannot
therefore go out internally but has to externally
even if it stays there it matters not as the plaster acts as a dpm

Chris

Well, overall, I'm happy to go with the majority vote that it's wet rot.

I've exposed the wall plate in two more locations, 1m and 2m to the left of
the rot centre and the plate is 100% sound.

I've pulled a couple of the short ceiling joists out which means I can see
right to the far end wall (0.5m to the right of the rot) and although the
plate is knackered there, surprisingly the roof rafter seems mostly fine.

No hairy stuff anywhere.

Reckon I can cut, remove and slide a new plate in, if I lift the roof 1/2"
with acrow props. I'll leave it open for now - it's no longer an urgent
job. Let it get baked out a bit in summer then do it.

Thanks for all your opinions

Cheers

Tim

[Context if needed...]

Tim S coughed up some electrons that declared:

Hi all,

Lots of work at the Bungalow today. All went well, until this, though:

http://photos.dionic.net/v/public/bungalow/mushroom/

Wonder if the phots are enough for someone to be able to cast an opinion
on whether it's dry or wet rot?

These are the timbers underneath a lead flat roof, on the side of the
building (which is otherwise hipped roofed).

Looks more like wet rot to me - but how can I be sure it's not dry rot?

If it's wet rot, then I can replace the visible section of wall plate and
one flat roof rafter (which is separate to the main roof rafters) and one
ceiling joist.

If it's dry rot, then I'm scared... Presumably that means new flat roof
time, due to having to cut back 2-3 feet from the affected areas?


More background:

I didn't see any "cotton wool" nor fruiting bodies. Not sure what the
white staining is, but it's not hairy.

The neighbour told me that the roof used to be felted, and was leaded
10-15 years back - presumably there could have been a serious leak then.
It's generally dry now.

The rafter has rotted completely at the end, and is apparantly all right,
otherwise *except* that the core has rotted for about another 8" (needed
to jab a chisel in to discover that).

The wall plate is totally gone a foot either side, but neighbouring
rafters seem fine. The wall plate has bottom half rot for all the visible
parts, but on the far left, it's petered down to perhaps only 1/8" is
dodgey.

Looks like the water got into the inner wall leaf, then rotted the wall
plate from beneath.

The planks supporting the lead seem solid and as you can see, not problems
at all at the other end, where the main hipped roof rafters sit.

Thanks *very* much in advance

Cheers

Tim

On Mar 8, 5:57*pm, (Andrew Gabriel) wrote:
It will carry the water from one site to
another, in order to infect timber which wouldn't otherwise be
susceptable, hence its ability to infect dry timber, unlike wet
rot.

It can conduct water, but dry rot has no ability to wet up dry timber.
Dry rot cannot attack dry timber. The same as every other brown rot.

It was not named 'dry rot' because it attacks dry timber.

You won't be able to get any fungicide nowadays which will protect
against anything, and there never was one which was particularly
effective against dry rot (it's one of the most resistant fungi).

Do you want to back that up at all? Because it dies when surface
sprayed with boron, propaconazole, Jeyes fluid....It was never
particularly tollerant of CCA pre-treatments either. Trametes
versicolor, perhaps, but not Serpula lacrymans.


Matt
-I particularly liked the comment further up about it growing readily
outdoors- so readily that a expedition had to be mounted to the
Himalyas to find it! There are still only about five recorded
instances of outdoor growth in the world.