Cold bedrooms, condensation on curved ceilings.

[SimonH2]

I'll post a link later (out at moment) - there's a site that sells seconds at a fraction of the price. Typically a little out on dimensions while the factory has been getting the machine right and that sort of thing.

 

[endecotp]

there's a site that sells seconds at a fraction of the price.

“Seconds and Co”.
But I don’t think they normally do insulated plasterboard, do they?
It’s generally cheaper to buy the insulation and the plasterboard separately.

 

[SimonH2]

That's them
https://www.secondsandco.co.uk/

Seems they do have insulated plasterboard
https://www.secondsandco.co.uk/product-page/kingspan-ecotherm-xtratherm-plasterboard

Of course, what they have available at any point in time depends on how badly the manufacturers have been meeting their quality standards recently. I.e., how much "scrap" they've made.

BTW, if you do decide to buy from them, make sure you read their delivery information. They deliver on set days, so you get stuff on the day(s) their wagon is in your area. And have an honest conversation with yourself as to how bulky (and for insulated plasterboard, heavy) it is and where you are going to put it between delivery and use. It's easy to under estimate the volume

 

[plastic_peanut]

Just reporting back for anyone else that has similar issues,

I used the Knauf dritherm glass wool boards ( 1200x46x75cm) from B&Q.

Using the earlier advice I trimmed the full board to the width of the rafters and then cut the board in half.
Next I cut one half diagonally in two. These were then fitted into position deep into the eaves using a rod to push them into position.
The distance between the joist was measured and then the second half of the slab was cut to size. This butted up to the slabs on the eaves and ran under the loft insulation installed earlier.

I am pleased to report this has made a huge difference in the bathroom and has waved good bye to the mould issues we were seeing.

The insulation comes in packs of six and after using 5 packs I will need a sixth pack as i will be a couple of boards short across the top of the stairs.

Would recommend a two man team otherwise it would be very time consuming but certainly worth going to the trouble.

I also fitted 10 lap vents just in case air flow was restricted but haven’t had any condensation issues

 

[Keithmac]

Just reporting back for anyone else that has similar issues,

I used the Knauf dritherm glass wool boards ( 1200x46x75cm) from B&Q.

Using the earlier advice I trimmed the full board to the width of the rafters and then cut the board in half.
Next I cut one half diagonally in two. These were then fitted into position deep into the eaves using a rod to push them into position.
The distance between the joist was measured and then the second half of the slab was cut to size. This butted up to the slabs on the eaves and ran under the loft insulation installed earlier.

I am pleased to report this has made a huge difference in the bathroom and has waved good bye to the mould issues we were seeing.

The insulation comes in packs of six and after using 5 packs I will need a sixth pack as i will be a couple of boards short across the top of the stairs.

Would recommend a two man team otherwise it would be very time consuming but certainly worth going to the trouble.

I also fitted 10 lap vents just in case air flow was restricted but haven’t had any condensation issues

Sounds a great result!, will have to sort mine out this year.

 

[plastic_peanut]

Definitely recommend it. Big shout to Mfarrow for the suggestion on the diagonal cuts. This makes life so much easier and holds the insulation in place.

 

[JRC81]

Thank you to everyone that has contributed to this thread. Our house has longstanding issues with cracked plaster, condensation and mould on the curved ceilings in the box bedroom and bathroom. Despite trying to improve heating, ventilation and using desiccant dehumidifiers in the effected rooms this has not been resolved. With the information on the thread I was able to tell my roofers exactly how to insulate between the rafters (photo attached). I'm hopeful this will make a big difference and I will look to redecorate in the New Year.