loft insulation in an older property

fishpond

Property built in 1922, had 4 tenants in the top floor (shop below), since loft insulation has been installed, 3 of the 4 tenants have complained about mould and damp--the other tenant religiously opened windows every day (summer and winter).
I am now wondering whether to have the loft insulation moved from above the kitchen, bathroom and around the edges.
Property had never suffered damp since at least 1990 until loft insulation was installed 5 years ago
Any thoughts?
(I suppose tenants could expel more air because of Brexit, but that would be a new thread)

smmeadow

We just had a damp and timber survey done on our house and the guy advised us not to add more insulation in the loft as it will reduce ventilation and cause more condensation in the house. Our house is old too 1935. I am no expert though, new houses are packed full with insulation. Perhaps they are better ventilated within the house? I would be interested to hear from someone who is an expert

G_M

I'd improve the ventilation.

* extractor fans in kitchen/bathroom?
* double glazing with trickle vents?
* ventillation bricks?

If there's nowhere outside to dry clothes, then a tumble dryer with external vent?

Norman_Castle

Did you improve the draught proofing at the same time as insulating the loft? Newly insulated loft hatches which previously let moist air escape? I'm in a 1900 attic flat which while I've lived here has had the draughty tiled roof replaced with a felted and tiled roof and minimal insulation replace with better insulation. Neither has increased damp or mold.

Hoploz

It's possible that the loft insulation has been fitted too close to the edge meaning it is blocking air flow and the roof void has insufficient ventilation. This could be solved by moving the insulation away from the edges.

G_M

Hoploz wrote: »

It's possible that the loft insulation has been fitted too close to the edge meaning it is blocking air flow and the roof void has insufficient ventilation. This could be solved by moving the insulation away from the edges.

But.... that would result in damp/mould in the attic, not in the flat beneath the insulation.

Whether the attic does now have a damp problem is not mentioned - it's the flat that needs better ventilation though.