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Default Black mould on underside of roof felt

I've just been up into our loft and was horrified to find what appears to be black mould on the underside of the roof felt:

https://thumbsnap.com/Ijt6WPKP
https://thumbsnap.com/w3zVIJbI

(Note: The white 'strips' are where the felt is overlapped)

I haven't been up there since last summer and I am certain it wasn't like that then (or at any time previously).

The house was built in 2007 and the felt appears to be of the breathable variety (it looks like a teabag when viewed close-up) however I am assuming that even a breathable felt can't work miracles if there's excessive moisture being generated in the house, particularly given how dirty the felt appears to be on the tile side? There appears to be no eaves ventilation (hard to tell as it's a 2.5 storey house so the top bedroom has hipped ceilings which mean the eaves aren't visible from the loft space).

We have a nearly-2yr old toddler and have also been undertaking a fair bit of building work over the last six months and so I think a combination of more vegetable steaming than we used to, extra loads of washing, great house occupation, reduced ventilation to 'keep the baby warm' etc have all contributed to an excess of moisture and it has condensed on the cold surface in the loft over the winter months.

If the above is true then I am sure we can remove the cause through lifestyle adjustment, however I am still concerned about the mould that is already present. Should I try and clean/remove it? If so, how and what with? It looks like most of the black mould spray cleaners contain bleach (to kill the mould and remove the staining?) and so wondered if this might damage the felt? Perhaps something without bleach more geared towards mould removal off fabric/furniture? If I just left it (and cured the cause) might some of it disappear anyway?
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Default Black mould on underside of roof felt

On Sunday, 12 May 2019 11:52:42 UTC+1, Mathew Newton wrote:

I've just been up into our loft and was horrified to find what appears to be black mould on the underside of the roof felt:

https://thumbsnap.com/Ijt6WPKP
https://thumbsnap.com/w3zVIJbI

(Note: The white 'strips' are where the felt is overlapped)

I haven't been up there since last summer and I am certain it wasn't like that then (or at any time previously).

The house was built in 2007 and the felt appears to be of the breathable variety (it looks like a teabag when viewed close-up) however I am assuming that even a breathable felt can't work miracles if there's excessive moisture being generated in the house, particularly given how dirty the felt appears to be on the tile side? There appears to be no eaves ventilation (hard to tell as it's a 2.5 storey house so the top bedroom has hipped ceilings which mean the eaves aren't visible from the loft space).

We have a nearly-2yr old toddler and have also been undertaking a fair bit of building work over the last six months and so I think a combination of more vegetable steaming than we used to, extra loads of washing, great house occupation, reduced ventilation to 'keep the baby warm' etc have all contributed to an excess of moisture and it has condensed on the cold surface in the loft over the winter months.

If the above is true then I am sure we can remove the cause through lifestyle adjustment, however I am still concerned about the mould that is already present. Should I try and clean/remove it? If so, how and what with? It looks like most of the black mould spray cleaners contain bleach (to kill the mould and remove the staining?) and so wondered if this might damage the felt? Perhaps something without bleach more geared towards mould removal off fabric/furniture? If I just left it (and cured the cause) might some of it disappear anyway?


Bleach is the stuff to use on mould. When that's not usable I've used copper sulphate.
Is it mould though?


NT
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Default Black mould on underside of roof felt

I guess there isnt enough ventilation in the roof,
has someone added lots of glass fibre and blocked the vents at the eaves?

A humidity controlled fan in kitchen bathroom and laundry room will help.

[george]

On Sunday, May 12, 2019 at 11:52:42 AM UTC+1, Mathew Newton wrote:
I've just been up into our loft and was horrified to find what appears to be black mould on the underside of the roof felt:

https://thumbsnap.com/Ijt6WPKP
https://thumbsnap.com/w3zVIJbI

(Note: The white 'strips' are where the felt is overlapped)

I haven't been up there since last summer and I am certain it wasn't like that then (or at any time previously).

The house was built in 2007 and the felt appears to be of the breathable variety (it looks like a teabag when viewed close-up) however I am assuming that even a breathable felt can't work miracles if there's excessive moisture being generated in the house, particularly given how dirty the felt appears to be on the tile side? There appears to be no eaves ventilation (hard to tell as it's a 2.5 storey house so the top bedroom has hipped ceilings which mean the eaves aren't visible from the loft space).

We have a nearly-2yr old toddler and have also been undertaking a fair bit of building work over the last six months and so I think a combination of more vegetable steaming than we used to, extra loads of washing, great house occupation, reduced ventilation to 'keep the baby warm' etc have all contributed to an excess of moisture and it has condensed on the cold surface in the loft over the winter months.

If the above is true then I am sure we can remove the cause through lifestyle adjustment, however I am still concerned about the mould that is already present. Should I try and clean/remove it? If so, how and what with? It looks like most of the black mould spray cleaners contain bleach (to kill the mould and remove the staining?) and so wondered if this might damage the felt? Perhaps something without bleach more geared towards mould removal off fabric/furniture? If I just left it (and cured the cause) might some of it disappear anyway?


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Default Black mould on underside of roof felt

On Sunday, 12 May 2019 12:17:38 UTC+1, wrote:
On Sunday, 12 May 2019 11:52:42 UTC+1, Mathew Newton wrote:

I've just been up into our loft and was horrified to find what appears to be black mould on the underside of the roof felt:

https://thumbsnap.com/Ijt6WPKP
https://thumbsnap.com/w3zVIJbI

(Note: The white 'strips' are where the felt is overlapped)

I haven't been up there since last summer and I am certain it wasn't like that then (or at any time previously).

The house was built in 2007 and the felt appears to be of the breathable variety (it looks like a teabag when viewed close-up) however I am assuming that even a breathable felt can't work miracles if there's excessive moisture being generated in the house, particularly given how dirty the felt appears to be on the tile side? There appears to be no eaves ventilation (hard to tell as it's a 2.5 storey house so the top bedroom has hipped ceilings which mean the eaves aren't visible from the loft space).

We have a nearly-2yr old toddler and have also been undertaking a fair bit of building work over the last six months and so I think a combination of more vegetable steaming than we used to, extra loads of washing, great house occupation, reduced ventilation to 'keep the baby warm' etc have all contributed to an excess of moisture and it has condensed on the cold surface in the loft over the winter months.

If the above is true then I am sure we can remove the cause through lifestyle adjustment, however I am still concerned about the mould that is already present. Should I try and clean/remove it? If so, how and what with? It looks like most of the black mould spray cleaners contain bleach (to kill the mould and remove the staining?) and so wondered if this might damage the felt? Perhaps something without bleach more geared towards mould removal off fabric/furniture? If I just left it (and cured the cause) might some of it disappear anyway?


Bleach is the stuff to use on mould. When that's not usable I've used copper sulphate.
Is it mould though?


To be honest I am just assuming it us, because it's arrived seemingly so suddenly - I've got photos from previous jobs over the years in the loft which show how clean the felt has always been:

https://thumbsnap.com/7CssXGzL

(This one admittedly taken in 2011)

Whilst we don't have any issues of condensation and/or mould elsewhere in the house I have noticed when coming home after work how humid the air has been when my wife has been drying clothes indoors and steaming the nipper's vegetables (sound awful!). Putting two and two together I am assuming this warm moist air has risen up through less-then-perfectly-sealed upper floor ceiling and condensed on the felt.

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Default Black mould on underside of roof felt

On Sunday, 12 May 2019 12:21:24 UTC+1, George Miles wrote:
I guess there isnt enough ventilation in the roof,
has someone added lots of glass fibre and blocked the vents at the eaves?


I don't think there is any eaves ventilation on these houses; certainly looking at the soffits there's no obvious vent holes and I had always assumed that the breathable felt was the reason why (accepting it only probably works in conjunction with a reasonably ventilated house below).

A humidity controlled fan in kitchen bathroom and laundry room will help.


Funnily enough I am actually in the process of taking advantage of the building work going on to install a whole-house MVHR system; having been planning it for ages - not for any specific problem to solve but just because I like the idea on how it works and stumbled across a nearly-new unit at a bargain price.


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Default Black mould on underside of roof felt

On Sunday, 12 May 2019 12:17:38 UTC+1, wrote:

Bleach is the stuff to use on mould. When that's not usable I've used copper sulphate.


I've been reading that a solution of Hydrogen Peroxide 3% w/w can work well and is not as damaging as bleach can be?
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Default Black mould on underside of roof felt

On 12/05/2019 11:52, Mathew Newton wrote:
I am still concerned about the mould that is already present. Should I try and clean/remove it?


I wouldn't bother. It'll die when conditions are no longer suitable.

The bigger question is how is the damp getting into the loft. I don't
suppose you have a bathroom extractor that vents into the loft instead
of outside?

Andy
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Default Black mould on underside of roof felt

On Sunday, 12 May 2019 21:51:51 UTC+1, Vir Campestris wrote:

I wouldn't bother. It'll die when conditions are no longer suitable.


I've found that vacuuming it makes it far less noticeable, so perhaps that might be suggesting it is not all mould (i.e. also general dirt). That or I've just blown mould spores out from the vacuum extract!

The bigger question is how is the damp getting into the loft. I don't
suppose you have a bathroom extractor that vents into the loft instead
of outside?


All extractor's are properly vented, however in typical new-build fashion the house has dot-and-dabbed plasterboard walls but in something of a 'plasterboard tent' form which almost certainly creates some airways all the way from the the ground floor upto the loft. With the ground floor currently stripped back bare to build an open-plan extension it wouldn't surprise me if warm, moist, air is rising up behind the plasterboards all the way to the loft. I'll be foaming up around the ground floor perimeter when I get a chance so if that's is a contributory factor that should help.

All that said, I've just dug some loft photos out from last year and they do show something similar so I am now thinking it might not be as 'new' as I thought, and perhaps more also not be as much mould as I thought either.

Might just keep an eye on it, and as mentioned, improve our ventilation prior to the MVHR going in.
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Default Black mould on underside of roof felt

Yes I was wondering about that and indeed whether a bit of condensation from
the causes mentioned would be enough to create it.
After all it has to have come from somewhere, and I was thinking another
moisture source from evaporating hot water or somesuch.
Brian

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On Sunday, 12 May 2019 11:52:42 UTC+1, Mathew Newton wrote:

I've just been up into our loft and was horrified to find what appears to
be black mould on the underside of the roof felt:

https://thumbsnap.com/Ijt6WPKP
https://thumbsnap.com/w3zVIJbI

(Note: The white 'strips' are where the felt is overlapped)

I haven't been up there since last summer and I am certain it wasn't like
that then (or at any time previously).

The house was built in 2007 and the felt appears to be of the breathable
variety (it looks like a teabag when viewed close-up) however I am
assuming that even a breathable felt can't work miracles if there's
excessive moisture being generated in the house, particularly given how
dirty the felt appears to be on the tile side? There appears to be no
eaves ventilation (hard to tell as it's a 2.5 storey house so the top
bedroom has hipped ceilings which mean the eaves aren't visible from the
loft space).

We have a nearly-2yr old toddler and have also been undertaking a fair bit
of building work over the last six months and so I think a combination of
more vegetable steaming than we used to, extra loads of washing, great
house occupation, reduced ventilation to 'keep the baby warm' etc have all
contributed to an excess of moisture and it has condensed on the cold
surface in the loft over the winter months.

If the above is true then I am sure we can remove the cause through
lifestyle adjustment, however I am still concerned about the mould that is
already present. Should I try and clean/remove it? If so, how and what
with? It looks like most of the black mould spray cleaners contain bleach
(to kill the mould and remove the staining?) and so wondered if this might
damage the felt? Perhaps something without bleach more geared towards
mould removal off fabric/furniture? If I just left it (and cured the
cause) might some of it disappear anyway?


Bleach is the stuff to use on mould. When that's not usable I've used copper
sulphate.
Is it mould though?


NT


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Default Black mould on underside of roof felt

In article ,
Vir Campestris wrote:
On 12/05/2019 11:52, Mathew Newton wrote:
I am still concerned about the mould that is already present. Should I try and clean/remove it?


I wouldn't bother. It'll die when conditions are no longer suitable.


The bigger question is how is the damp getting into the loft. I don't
suppose you have a bathroom extractor that vents into the loft instead
of outside?


Andy


Is there an open water tank feeding a heating system?

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle


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Default Black mould on underside of roof felt

On Monday, 13 May 2019 08:17:26 UTC+1, charles wrote:

Is there an open water tank feeding a heating system?


No, we have a sealed system (and unvented cylinder for HW).
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Default Black mould on underside of roof felt

I'm starting to wonder that myself Brian. Certainly I couldn't see any 'fur' that I've seen accompanying black mould I've seen in other houses / on the web, indeed there doesn't look to be any 3D properties to what I've got as far as I can tell.

On Monday, 13 May 2019 07:23:59 UTC+1, Brian Gaff wrote:
Yes I was wondering about that and indeed whether a bit of condensation from
the causes mentioned would be enough to create it.



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Default Black mould on underside of roof felt

Forgot to add that there's no musty smell up there either and so I am really starting to have doubts now...

On Monday, May 13, 2019 at 1:50:59 PM UTC+1, Mathew Newton wrote:
I'm starting to wonder that myself Brian. Certainly I couldn't see any 'fur' that I've seen accompanying black mould I've seen in other houses / on the web, indeed there doesn't look to be any 3D properties to what I've got as far as I can tell.

On Monday, 13 May 2019 07:23:59 UTC+1, Brian Gaff wrote:
Yes I was wondering about that and indeed whether a bit of condensation from
the causes mentioned would be enough to create it.


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On 13/05/2019 15:33, Mathew Newton wrote:
Forgot to add that there's no musty smell up there either and so I am really starting to have doubts now...

On Monday, May 13, 2019 at 1:50:59 PM UTC+1, Mathew Newton wrote:
I'm starting to wonder that myself Brian. Certainly I couldn't see any 'fur' that I've seen accompanying black mould I've seen in other houses / on the web, indeed there doesn't look to be any 3D properties to what I've got as far as I can tell.

On Monday, 13 May 2019 07:23:59 UTC+1, Brian Gaff wrote:
Yes I was wondering about that and indeed whether a bit of condensation from
the causes mentioned would be enough to create it.



It looks like the black lichen spots that you get on patios that
are only cleaned once in a blue moon.

Do you have a combi boiler or are there tanks in the loft ?.

If the latter, are they fitted with snug-fitting lids and
insulated ?.

If you have expansion/overflow tank for the heating system,
is there any possibility of pumping over ?.
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Default Black mould on underside of roof felt

On 12/05/2019 12:21, George Miles wrote:
I guess there isnt enough ventilation in the roof,
has someone added lots of glass fibre and blocked the vents at the eaves?


I don't think they bother these days if the roof is constructed
with a breathable membrane under the tiles.

A cul-de-sac of social houses near me included a specially
adapted house for a wheelchair-bound lady.

I think a lift was installed but she ended up almost bedbound.

A few years after being built I noticed that some vents had
been addded to the flanks of the roof, two on each side of
the ridge half way down. I guess with her living upstairs
with the heating on full blast, a lot of hot moist air must
have permeated into the loft space.



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On 13/05/2019 13:46, Mathew Newton wrote:
On Monday, 13 May 2019 08:17:26 UTC+1, charles wrote:

Is there an open water tank feeding a heating system?


No, we have a sealed system (and unvented cylinder for HW).


Which answers a question I asked.

Did the builders use foil-backed plasterboard for the
upstairs ceilings (they should have).

Do you have downlighters in any of the upstairs rooms,
notably the bathroom ?. These will allow warm, moist
air to leak into the loft.

Ditto a badly fitted loft access hatch.

Then there is also the possibiluity that warm moist air
is getting into the cavity and the water vapour molecules
migrate up the cavity, into the soffitt space and then
back inside your loft.
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Default Black mould on underside of roof felt

the original poster has said that theres lots of steam from laundry and boiling which is maybe getting up[ behind plasterboard - it will find a way up there as theres a pressure difference!

And he's working on a second hand MVHR

So I'd make the holes for MVHR and get it working without the complicated heat recovery stuff and see if that solves the condensation, if not put in more air vents.

(may have to wait till winter to fully test it)

I've insulated above my attic floor with wool and kingspan so i can have lots of draughts in the attic.

a dehumidifier in the attic wouldnt be a long term solution,
anyhow with this week of hot weather it just needs lots of draughts and it will dry out.

a humidity meter with hourly readings and a graph?

https://www.designingbuildings.co.uk/wiki/Dew_point


https://www.google.com/search?q=insulation+dewpoint

george
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On Tuesday, 14 May 2019 15:47:13 UTC+1, George Miles wrote:

So I'd make the holes for MVHR and get it working without the complicated heat recovery stuff and see if that solves the condensation, if not put in more air vents.


The unit is installed and I just need to fit the manifolds and route the pipes - will probably get a good chunk of it done this weekend.

(may have to wait till winter to fully test it)


Yes, most likely.

a dehumidifier in the attic wouldnt be a long term solution,
anyhow with this week of hot weather it just needs lots of draughts and it will dry out.


Nothing feels damp in there at all. Indeed I've got quite a few cardboard boxes and they all feel fine; none have that 'weakened' feel to them that happens when they've got previously got damp/cold.

a humidity meter with hourly readings and a graph?


I will be controlling the MVHR with a Raspberry Pi so might add a temperature+humidity sensor for the loft to keep an eye on things.
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On Tuesday, 14 May 2019 15:42:12 UTC+1, Andrew wrote:

Did the builders use foil-backed plasterboard for the
upstairs ceilings (they should have).


No, just paper-backed plasterboard and a skim coat.

Do you have downlighters in any of the upstairs rooms,
notably the bathroom ?. These will allow warm, moist
air to leak into the loft.


The only penetrations are lighting cables and an en suite extractor; all seemingly well sealed.

Ditto a badly fitted loft access hatch.


That too is pretty good - it's an insulated affair with a well fitting compressible rubber seal.

Then there is also the possibiluity that warm moist air
is getting into the cavity and the water vapour molecules
migrate up the cavity, into the soffitt space and then
back inside your loft.


Could well be; unfortunately I can't see if the cavities have been closed at the top due to the design of the roof.

I'll give the felt a good vacuum, and might test some hydrogren peroxide to see if that cleans it up. If I can get it back to a 'mould (or whatever it is) free' state then I can keep a proper an on it, perhaps with humidity monitoring as George suggested along with visible observations of the felt.
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On Tuesday, 14 May 2019 15:47:13 UTC+1, George Miles wrote:

anyhow with this week of hot weather it just needs lots of draughts and it will dry out.


Forgot to comment on this; everything feels bone dry. You would of course expect this with the current weather but there's no sign that anything has ever been damp other than the black marks on the felt.

One thing I haven't done is tried to look on the tile side of the felt - it could well be there's something on there that is causing the marks on the inside. I don't know what, if any, relevance this has but we're in a rural location any there must be a lot of pollen etc floating around which must get trapped on this teabag-like felt. In the past I've found the odd dead fly in the loft dangling from the felt with appears to be a leg stuck!


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Andrew Wrote in message:
On 13/05/2019 15:33, Mathew Newton wrote:
Forgot to add that there's no musty smell up there either and so I am really starting to have doubts now...

On Monday, May 13, 2019 at 1:50:59 PM UTC+1, Mathew Newton wrote:
I'm starting to wonder that myself Brian. Certainly I couldn't see any 'fur' that I've seen accompanying black mould I've seen in other houses / on the web, indeed there doesn't look to be any 3D properties to what I've got as far as I can tell.

On Monday, 13 May 2019 07:23:59 UTC+1, Brian Gaff wrote:
Yes I was wondering about that and indeed whether a bit of condensation from
the causes mentioned would be enough to create it.



It looks like the black lichen spots that you get on patios that
are only cleaned once in a blue moon.

Do you have a combi boiler or are there tanks in the loft ?.

If the latter, are they fitted with snug-fitting lids and
insulated ?.

If you have expansion/overflow tank for the heating system,
is there any possibility of pumping over ?.


Do read the F thread...
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there was cold air the other side of the roofing felt which is why condensation happened there, not anywhere else.

[george]

On Tuesday, May 14, 2019 at 8:13:18 PM UTC+1, Mathew Newton wrote:
On Tuesday, 14 May 2019 15:47:13 UTC+1, George Miles wrote:

anyhow with this week of hot weather it just needs lots of draughts and it will dry out.


Forgot to comment on this; everything feels bone dry. You would of course expect this with the current weather but there's no sign that anything has ever been damp other than the black marks on the felt.

One thing I haven't done is tried to look on the tile side of the felt - it could well be there's something on there that is causing the marks on the inside. I don't know what, if any, relevance this has but we're in a rural location any there must be a lot of pollen etc floating around which must get trapped on this teabag-like felt. In the past I've found the odd dead fly in the loft dangling from the felt with appears to be a leg stuck!


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On Wednesday, 15 May 2019 17:32:57 UTC+1, George Miles wrote:
there was cold air the other side of the roofing felt which is why condensation happened there, not anywhere else.


If it was as straightforward as that I would have expected the overlaps to have suffered similarly as there'd be very little, if any, temperature difference there.

Some have questioned whether it really is mould and I am leaning towards that too; not due to wishful thinking but rather that the basis of the initial hypothesis is not looking strong.

I'll given the felt a vacuum, try some of the hydrogen peroxide that arrived today, and see how things go from there. Finger's crossed I won't see it again or, if I do, it'll be in another few years time as appears to have been the case here which should point to it being something more benign than a ventilation/mould issue.
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On 15/05/2019 11:24, Jim K.. wrote:
Andrew Wrote in message:
On 13/05/2019 15:33, Mathew Newton wrote:
Forgot to add that there's no musty smell up there either and so I am really starting to have doubts now...

On Monday, May 13, 2019 at 1:50:59 PM UTC+1, Mathew Newton wrote:
I'm starting to wonder that myself Brian. Certainly I couldn't see any 'fur' that I've seen accompanying black mould I've seen in other houses / on the web, indeed there doesn't look to be any 3D properties to what I've got as far as I can tell.

On Monday, 13 May 2019 07:23:59 UTC+1, Brian Gaff wrote:
Yes I was wondering about that and indeed whether a bit of condensation from
the causes mentioned would be enough to create it.


It looks like the black lichen spots that you get on patios that
are only cleaned once in a blue moon.

Do you have a combi boiler or are there tanks in the loft ?.

If the latter, are they fitted with snug-fitting lids and
insulated ?.

If you have expansion/overflow tank for the heating system,
is there any possibility of pumping over ?.


Do read the F thread...


Oh dear. Are you having Jeremy Kyle withdrawal symptoms ?.
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On 14/05/2019 20:07, Mathew Newton wrote:
On Tuesday, 14 May 2019 15:42:12 UTC+1, Andrew wrote:

Did the builders use foil-backed plasterboard for the
upstairs ceilings (they should have).


No, just paper-backed plasterboard and a skim coat.


well that is part of the problem. Water vapour molecules will
migrate through the ceiling and into the loft space. The
breathable membrane should cope with this but seems not to.

Modern building regs make foil-backed plasterboard
mandatory for upstairs ceilings, for precisely this reason,
but older re-roofed properties probably still need some normal
vents even if breathable membranes are fitted.

Lofts that have 300mm of rockwool are much colder, so
condensation is more of a problem.


snip




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Default Black mould on underside of roof felt

On 16/05/2019 16:48, Andrew wrote:
On 14/05/2019 20:07, Mathew Newton wrote:
On Tuesday, 14 May 2019 15:42:12 UTC+1, AndrewÂ* wrote:

Did the builders use foil-backed plasterboard for the
upstairs ceilings (they should have).


No, just paper-backed plasterboard and a skim coat.


well that is part of the problem. Water vapour molecules will
migrate through the ceiling and into the loft space. The
breathable membrane should cope with this but seems not to.

Modern building regs make foil-backed plasterboard
mandatory for upstairs ceilings, for precisely this reason,
but older re-roofed properties probably still need some normal
vents even if breathable membranes are fitted.

Lofts that have 300mm of rockwool are much colder, so
condensation is more of a problem.


snip



If your house was built in 2007 then it should have had foil-backed
plasterboard on all the upstairs ceilings.

I wonder if NHBC or similar did the 'building control' ?. Is this
a house built by one of the large national builders, or a small
local outfit ?.

Look at the pdf called "Re-roofing and Plastering" at Rochdale
council.

http://www.rochdale.gov.uk/planning-...gulations.aspx



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Default Black mould on underside of roof felt

On Thursday, May 16, 2019 at 5:15:34 PM UTC+1, Andrew wrote:

If your house was built in 2007 then it should have had foil-backed
plasterboard on all the upstairs ceilings.


Is that 'should' a 'should' or a 'must'? The document isn't clear on that point.

Note also that even if it were a 'must' then if that requirement only came in around 2006/2007 then it still might not apply to a 2007-built house if that house was built against plans agreed before 2006.

Is this
a house built by one of the large national builders, or a small
local outfit ?.


Persimmon.... (Enough said! ;-))

Thanks everyone for the comments; I'll keep an eye on things and so what happens.
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Default Black mould on underside of roof felt

On 16/05/2019 17:29, Mathew Newton wrote:
On Thursday, May 16, 2019 at 5:15:34 PM UTC+1, Andrew wrote:

If your house was built in 2007 then it should have had foil-backed
plasterboard on all the upstairs ceilings.


Is that 'should' a 'should' or a 'must'? The document isn't clear on that point.


Ahh. Building regs are notorious in their choice of words. I think in
the world of the BCO, 'should' means 'I won't sign it off until you
comply' !!


Note also that even if it were a 'must' then if that requirement only came in around 2006/2007 then it still might not apply to a 2007-built house if that house was built against plans agreed before 2006.

Is this
a house built by one of the large national builders, or a small
local outfit ?.


Persimmon.... (Enough said! ;-))

Oh dear. I bet if you drilled some holes into the cavities you would
find :-

1. no insulation
2. inch thick expanded polystyrene slabs chucked in loosely
allowing air to circulate on both sides
3. Plasterboard offcuts to avoid paying a landfill disposal
tax.

Sadly its too late to make a claim from the NHBC, who probably
did the building control. Your local authority BCO would have
spotted this and enforced remedial work.

Thanks everyone for the comments; I'll keep an eye on things and so what happens.


I think the addition of vents into the lower third of the flanks
(there are special vents for retrofitting) and maybe a ridge
vent would help.

I suspect that painting all the upstairs ceilings with oil-based
paint to create a vapour barrier would help, but you would have
to move out while the fumes clear. Don't try this without
doing some research.


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Default Black mould on underside of roof felt

On Thursday, 16 May 2019 18:34:54 UTC+1, Andrew wrote:

Oh dear. I bet if you drilled some holes into the cavities you would
find :-

1. no insulation
2. inch thick expanded polystyrene slabs chucked in loosely
allowing air to circulate on both sides
3. Plasterboard offcuts to avoid paying a landfill disposal
tax.


On the contrary; I've just removed the back wall and was actually quite impressed with the attention to detail: well fitting insulation boards, little in the way of mortar snots; clear cavity down to footings. This was the showhome, or possibly the 'office' next to it, and so was likely one of the first ones built hence the builder's perhaps still had some motivation in them!

Sadly its too late to make a claim from the NHBC, who probably
did the building control. Your local authority BCO would have
spotted this and enforced remedial work.


The thought never crossed my mind. From what I can gather from flicking through the Approved Documents (acknowledging that they don't hold exclusivity over what satisfies the regulations) I can't find anything that mandates even today the need for foil-backed plasterboard per se; more just that consideration must be made for vapour control.

I think the addition of vents into the lower third of the flanks
(there are special vents for retrofitting) and maybe a ridge
vent would help.

I suspect that painting all the upstairs ceilings with oil-based
paint to create a vapour barrier would help, but you would have
to move out while the fumes clear. Don't try this without
doing some research.


I won't be taking any action until I know for certain what, if any, problem I've actually got and what caused it.
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Default Black mould on underside of roof felt

Andrew Wrote in message:
On 15/05/2019 11:24, Jim K.. wrote:
Andrew Wrote in message:
On 13/05/2019 15:33, Mathew Newton wrote:
Forgot to add that there's no musty smell up there either and so I am really starting to have doubts now...

On Monday, May 13, 2019 at 1:50:59 PM UTC+1, Mathew Newton wrote:
I'm starting to wonder that myself Brian. Certainly I couldn't see any 'fur' that I've seen accompanying black mould I've seen in other houses / on the web, indeed there doesn't look to be any 3D properties to what I've got as far as I can tell.

On Monday, 13 May 2019 07:23:59 UTC+1, Brian Gaff wrote:
Yes I was wondering about that and indeed whether a bit of condensation from
the causes mentioned would be enough to create it.


It looks like the black lichen spots that you get on patios that
are only cleaned once in a blue moon.

Do you have a combi boiler or are there tanks in the loft ?.

If the latter, are they fitted with snug-fitting lids and
insulated ?.

If you have expansion/overflow tank for the heating system,
is there any possibility of pumping over ?.


Do read the F thread...


Oh dear. Are you having Jeremy Kyle withdrawal symptoms ?.


Seems clear that day time TV is where you get your "expertise" from...

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Jim K


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