loft problem

[steg]

My house is over 150 years old, had the loft insulated about 6 months ago, now there is a lot of white powdery stuff on sarkin boards and joists, looks a bit like efflorescence. Roof construction is slate on sarkin boards, no roof felt

Should i be worried?

What is best way to remove it, if i need too?

[Buenchico]

All that lovely (expensive) heat that used to escape through your loft was helping to keep it dry. Now that you've insulated the loft the damper conditions up there are encouraging fungal growths (which is almost certainly where the white powdery stuff is coming from).

Many moulds are reasonably harmless but dry rot (which is far from harmless) sometimes first appears as a white powder:
http://www.spectrumpe...com/Images/fungus.jpg
It would be wisest to get it checked out by an expert.

In the meantime check carefully to see whether there's any possible route for water ingress into your loft. (Use binoculars to look at your roof tiles). Despite its name, dry rot likes damp conditions. If you can get rid of the moisture you'll have won a major part of the battle against almost any type of fungal growth.

Chris

[steg]

i was hoping not to need to get specialist in, but if it could be dry rot i think i better.
thank you for your time and advice Chris

[The Builder]

Although I agree with what Chris has said, I just wanted to say that ,by far, the more common fungus in buildings is a Wet Rot ............. usually Cellar Fungus.
What puzzles me is that fungus thrives in humid conditions, so I would have expected it to show BEFORE extra insulation was laid. Perhaps it's shown up now because of the time of year.
No matter ........... fungus hates fresh air. The sarking board may be acting as a felt would if it were present .......... and preventing ventilation via the slates.
Do you have a gable end where vents could be installed? Crossflow is what's needed .......... opposite gable would be perfect.
Also......... simple diy job .............. an ordinary pump-up garden insecticide sprayer filled with something like Cuprinol 5-star all-purpose would do the job.

[The Builder]

............... opposite gables ........... I should have said

[steg]

cheers builder, yes it has both gables but it is stone built and the walls are about 2+ft thick solid. It does have a small roof window that can be opened but wasps have been coming in and building nests so it has been shut for about 4 weeks. never noticed the white stuff last time i was in loft so it could be only about 3-4 weeks old (but couldn't swear to it). there is a few slates that have come off due to nail rot so air + moisture will most likely be getting in but never noticed any bad wet patches when i have looked before.

[The Builder]

Ahhhh ......... nail sickness!
Ok,....... when someone's up there replacing the missing slates ( soon as possible pleeeease) have them fit some of these on each slope .......... no need for ducting, but make sure they cut a hole in the sarking board .......

http://www.screwfix.c...-Alpha%20Slate%20Vent

also ........ if you spray you'll discourage the wasps as well :o)

[steg]

ok that sounds fine builder,
we have a guy that comes twice a year to check slates and replace missing ones, i'll get him on to it

thank you very much for advice