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Curved part of bedroom ceiling

I have notice that the curved part of my bedroom ceilings are very hot to touch when the weather is warm and cold and damp when the whether is cold. So I get a lot of condensation in this area in the winter and sometimes always early morning no matter what the weather. What can be the problem. I think the area in question has no insulation but the rest of the ceiling has insulation in the loft. Just that area it is very hard to fit insulation in. I already open the windows to dry out the damp. I don't really want to take down the ceiling. Can it not be insulated from the outside. Should I just get someone to remove all of the attic insulation will that help. Or will that make the house extremely hot. Does anyone know anyone who can insulate it from the outside. Also how do I know if my roof needs new felt.

3 Answers from MyBuilder Insulation Installers

Best Answer

Ventilation is the key, ventilate the room (which will lower the atmospheric moisture able to condense), and ventilate the roof (which will do the same that side). Get into the loft and make sure the insulation isn't blocking airflow from the sloping part of the roof.

The only way to insulate that part of the roof would be to downtake the ceilings. Not great when you need to use the room, so try improving ventilation first.

Yes, it can be insulated from outside but much more work and much more expensive to scaffold, strip the roof and then put it all back together. Felt isn't necessary, it's mainly there to waterproof your roof during re-roofing. The lack of felt may also be a good thing on older roofs as there is more airflow to the timbers.

There's no need to take any insulation away, just make sure it isn't blocking good airflow.


Answered 14th Jun 2019

Sliding rigid insulation between the rafters (timber roof structure running from the apex to the eaves) may be the best way to introduce insulation. But if there is airflow between the insulation and the outer (loft side) of the ceiling /
skeiling then the effect will be almost zero. If the voids between rafters are uneven getting a good fit for rigid insulation will be a challenge. To work properly the insulation must be fitted precisely - tight to the loft side of the skeiling and tightly between the rafters.
“Airflow” / ventilation etc on the loft side, while it’s important for the loft space to be ventilated, will have no effect on condensation inside the room. Moisture vapour migrates from high humidity (ie inside the room) to low humidity - the loft.


Answered 14th Jun 2019

Having dealt with a number of similar lofts facing this problem,
These areas usually called sceilings or slopping ceilings can often be insulated with a suitable insulation board (rigid board), either polystyrene or kingspan.
Assuming there are no blockages, these can be cut to fit /slide down between joist from inside to he loft.
If these areas prove inaccessible
You could choose to insulate the ceiling areas from inside the room with a quality insulation covering (Wallrock kv600 thermal liner / or similar).
I have done a number of these (currently in process of applying to walls with similar problem).
Hope this helps


Answered 5th Jun 2019

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