MOULDY roof

[ratty4moley]

Hi all, being a newbeeee I get somewhat concerned each time I stumble across what I think is a problem. When I lifted the roof (National Hive) yesterday I noticed that inside the roof was covered with a dusting of mould. I have a closed cover board, the vents in the roof are not blocked, and the roof (6”) is in good condition. It seems to me that there is insignificant air flow in the roof space. Should I go through winter with a couple of matchsticks propping it up, or add a couple of WBC bee escapes, thus allowing greater air flow and allowing all kinds of little critters a winter home?? I suppose this mould is a potential problem to my bees or do others have this and it’s just one of those things. Advice please ??

 

[Finman]

.
Is it question about inner cover or space between inner cover and rain cover?

If inner cover inside the hive is mouldy, then you have not enough insulation. Inner cover is cold and its surface condensates and becomes moldy.

If the loft us moldy, do not let the hive Air rise to the loft. Shut openings to the
Loft.

 

[ratty4moley]

Cover Board is ok... it is the inner side of the roof that has the problem.

 

[Finman]

Cover Board is ok... it is the inner side of the roof that has the problem.

Then, it is insulation issue. At least 5 cm thick.

What materual is your inner roof? Some become moldy when it gets moisture.

 

[jenkinsbrynmair]

Cover Board is ok... it is the inner side of the roof that has the problem.

Shut off them pontless vents and glue a slab of 40/50mm celotex to the inside of the roof

 

[ratty4moley]

The mould is on the inner side of the roof top which is external ply with a galvanised outer cover. the rest of the roof's inner surfaces are ok, the closed cover board is ok. so I'll try fitting some insulation.
Thank you.

 

[enrico]

I think what people are trying to say is that the heat from the hive is condensing on the inside of the roof and causing damp and mould. If you put insulation on top of your crown board the heat will not go into the roof space and should solve your problem
E

 

[ratty4moley]

That sound like a good idea..... but is it ok to shut off the vents??

 

[ratty4moley]

OK, that explained it well, thank you.

 

[itma]

OK, that explained it well, thank you.

Even a no-hole plywood coverboard will not stop water vapour passing through.
A nice slab of Celotex provides both insulation and a vapour barrier to prevent the vapour reaching the cold roof metal.

 

[RogueDrone]

So if we are not letting the vapour vent out through the roof where does it go?

"Cold don't kill damp does" as often quoted on here.

Colin

 

[linoleum bonypart]

I managed to acquire some celotex from my local library renovation last week was in a skip....cut to size fits lovely in roof

 

[BeeJayBee]

So if we are not letting the vapour vent out through the roof where does it go?

The air inside the hive doesn't need to vent anywhere - why would it?

If you leave holes in the crown/feeder board open then the warm air inside the hive will move upwards and will condense against the colder roof - unless there's some insulation to stop it.

 

[RogueDrone]

is it not now going to condense on the cold side walls?

 

[itma]

is it not now going to condense on the cold side walls?

Only when the walls get so cold as to be below the current dew point.
And anyway, that isn't a problem as any condensation can simply drain down the sides and out through the OMF.


Two things are problematic.
Condensation on the coverboard that can drip onto the clustered bees
and
condensation on the underside of the roof metal (that ultimately rots the roof wood)
Both are mitigated by a slab of Celotex over a no-hole coverboard. (And a poly roof ...)

 

[itma]

So if we are not letting the vapour vent out through the roof where does it go?

Out and away with the air change through the OMF, rather than up until it condenses on the underside of the roof metal which is essentially at outside temperature.

 

[Millet]

This is my first hive and i had similar problem's.. the inside of the roof was not moldy but damp to look at.. i insulated it with 5 layer's of silver bubble wrap and the inner roof is now bone dry..

 

[MuswellMetro]

So if we are not letting the vapour vent out through the roof where does it go?

"Cold don't kill damp does" as often quoted on here.

Colin

the water vapour condenses at the coldest point which is the OPEN mesh in Open Mesh Floor below the cluster

if you leave the varroa monitoring board in the it will condense on that, so you leave that out unless montoring (but you need to insualted above the crown board...
.veiw it as two methods of living, a BBKA draughty victorian house with large coal fire and frost on the bedroom windows and a BKForum modern house with highly insulated roof and small gas bill###but dont mix the two methods

 

[user 6228]

So if we are not letting the vapour vent out through the roof where does it go?

"Cold don't kill damp does" as often quoted on here.

Colin

the quotation is tautolgy
you only get condensation with colder surfaces i.e. below the dew point.
Damp from condensation is a result from heat escaping from the nest.

thus it should read "when its damp its still cold and that kills"
and when you have damp walls the nest is actually being dessicated by air at low relative humidity

 

[MuswellMetro]

the other BBKA view is that warmer bees use more stores in winter....poppycock

if you have a modern poly hive (they are unventilated except OMF with sold plastic crown boards), the main problem i have with them is too much stores left in spring so sometimes i have to spin some off 14x12 frames to make space for the queen to lay