Thatch, and keeping a building warm

[shobo]

Afternoon,
A query to anyone lucky enough (includes me, newly) to own a thatched cottage.
Its well understood how in cold weather it is advisable to keep an empty house, any house, warm. Cold air holds more moisture, and particularly if the weather airstream is moisture laden, the house could get condensation damp.
Someone, apparently knowledgeable, said to me the other day that this could be of particular concern to thatch. An unheated empty thatched cottage, in cold weather, could get high moisture level in the roof space, causing damp spores to break out in the thatch and for it to decay from the inside out by a rotting process.
Sounds plausible. There will be many factors at play, for instance it probably isn't a concern if the roof space is ventilated, yet if its not ventilated the only source of damp air may be from inside the house ie when it is occupied.
Does anyone have any knowledge / views / experience, please ?

 

[Andys]

We have a tremendous draught through our loft space which I suppose negates the insulating effect of the thatch. It keeps it dry though.
We do get some drips around the chimney area in certain weather conditions and we ought to Do Something but in the mean time the polythene-and-bucket system dries out rapidly afterwards.

It's colder air which can hold less moisture than warm air (which is why the colder, but drier, air from the aircon clears the car windscreen of condensation even in winter) - As far as I'm aware problems arise when warm, moist air from the living space condenses out on cold surfaces - which is where the ventilation helps by carrying away that which re-evaporates and limiting the opportunity for mould growth.

I suppose it comes down to a team effort between heat and ventilation to keep the moisture on the move!

 

[88v8]

Our underthatch roof space is reassuringly draughty.
And where rooms sit directly under the thatch, it's daubed on the underside, so either way, no damp.

As thatch goes through its lifespan the upper courses begin to rot and during winter will become permanently damp. But what came off our roof during the recent decennial re-ridge was more like compost. No mould.
So provided your thatch is either undercoated or well ventilated. I wouldn't worry about it.

Just start saving up for the next round of maintenance. Thatch; a rich man's roof.

Ivor