Cold bedrooms, condensation on curved ceilings.

Joined
18 Oct 2010
Messages
15
Reaction score
1
Location
Essex
Country
United Kingdom
My end of terrace house was built in 1953. I have lived here for 3 years now. The bedrooms are freezing cold, they have a ceiling that curves towards the windows, which starts about 18 inches into the room. The loft space is flat into the eves which means that there must be an empty cavity in the curved area? I have insulated the loft with 300+mm of cross layed insulation, but did'nt find any change in room temperatures. When touching the flat ceiling, it does not feel especially cold, but the curved area is very cold and this is resulting in condensation forming and mould developing in all upstair rooms. Can anyone suggest a way of insulating this void? I can only think of boring some holes in the loft space and filling with some expanding foam. But I dont want to make the problem worse than it already is. My 5 year old really needs this house to be warmer! Thanks, Charlie.
 
Sponsored Links
Raked ceilings are commonly overlooked when it comes to insulation which is a problem because all that separates you from the outside is a 100mm rafter and a few tiles!

Foam board insulation (celotex, kingspan, quintherm etc) is used both between AND across the rafter then plasterboard and skim. This method also requires an air gap on the cold side between the insulation and the roofing material.
 
So to expand your answer , noseall, are you saying remove the ceiling and insulate ?
correct.

Unless you are prepared to put up with the bulk of 125mm+ of insulation below the rafters, then insulating betwixt as well as beneath is the only way.
 
Sponsored Links
The uninsulated area where the plaster is attachesd directly to the rafters will have a "U" value of no less than 2.5 about 10 times that of the latest regs. If you fix just 25mm celotex under the existing platerboard and reline this with 9.5mm plasterboard using long plasterboard screws to fix into the rafters you will reduce the "U" value to less than 0.6, not quite latest regs but still a 77% reduction in heat loss
I have done this for clients that have been very pleased with the results, I f the roof is qite curved, 2x12mm insulation boards will bend more easily.
 
thanks for that information Tangowaggon. That would certainly be more feasible for me than to remove the ceiling. I hope to have my cavity walls filled in the next few weeks, do you think that there is any possibility that the same insulation could be blown into that ceiling cavity, or am I being naive? Cheers, Charlie.
 
Results of insulation performance may vary from room to room.

For instance, the North-East side of the building may fare less well than say the south west side particularly if say the bathroom or a condensation laden room happens to be on the N-E side.

Be prepared for disappointment should you skimp on the inso'.
 
Hi again. I am about to start to remove my ceilings and insulate using 50mm Celotex. I know it has been a long time coming but im finally ready to start. Any information as to which plasterboard I should use, and I will be using 25mm Celotex across the joists as I cannot really lose too much room space. Noseall gave me some good advice before, hope he can steer me right again! Thanks, Charlie.
 
Have you considered removing the tiles and insulating from above?

I did this in our 1920's house and it was much easier to do as there was no need to bring down the plaster in those areas.
 
Thanks Lower. Funny enough, someone suggested that to me the other day. It sounds much simpler as you say, Im not that crazy about the disruption taking down part of the ceiling will cause. I have never removed roof tiles, and it sounds like it would be a job best done from a platform rather than off a ladder?
The other thing is that I would not be able to insulate between the rafters and the plaster. My bedrooms are freezing, even with the radiators on. I need to use an electric convector to heat my 6 year olds room or else he gets constant colds. Do you know if I will notice the benefit of insulating these ceilings? Im looking for some encouragement really!
Still, it is well worth looking at, thanks again, Charlie.
 
Yes you are right. Those figures sound impressive. As the radiators are directly below the raked ceiling, Im sure that the heat rises and hits the cold part of the ceiling which cools the hot air instantly! Does anyone know why they adopted this type of ceiling in some houses? Was it purely aestetic, or was there another reason?
 
Without seeing your house and what the access is like its difficult to comment.

We had a flat roof below the area that needed the tiles removing so i did it off a step ladder. However, scaffold towers aren't that expensive to hire for a week or so.

It made a huge difference in our house. We had 50mm of insulation above the room and nothing above the curve of the ceiling. I put another 200mm of insulation above the room which made a bit of difference, but insulating above the curve made the difference between the heating being on full whack and only just keeping the room warm and the room feeling warm without the heating needing to go full blast.
 
I really appreciate your comments Lower. Its good to hear from someone who has had similar experience and success with insulation. I have a flat roof conservatory that I could work from at the rear.
I keep thinking about the rafters and the lack of insulation on them. I may lift a few tiles just to see what it looks like under there though.
Thanks again, Charlie.
 
Why not just cut out a rectangle of plasterboard between the joists that you can climb through ?

Much safer and easier than climbing ladders and lifting tiles and not much work to fix afterwards.
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Sponsored Links
Back
Top