We live in a single storey, flat-roofed house which I'd like to insulate. Has anyone used insulating boards on their ceilings? Are they effective? Any disadvantages? Advice on types of insulation and brands would be appreciated.

You might regret it in July/August!

The roof surface is red hot on summer days raising the internal temerature.

Hello,
Has anyone experienced problems with a) getting their British p/port renewed from Australia, and if so, how, and b) have they found that any questions that they may ask of the HMPO email service re. certain matters that are of concern to them or need clarification before the application AND PAYMENT are made, seem not to be given a straight answer, but one is simply referred back to the 'Notes' pages for an answer. Well, I wouldn't have sent the email if the answer was quite obviously there. Considering that there is, essentially, a no-refund policy in place for a failed application, it would be good to be assisted as much as possible with any queries a person may have. Any experiences on such would be welcome.

worldwatcher.

If the ceiling height allows you should consider a suspended ceiling with insulation laid behind. Alternatively it may be possible to place rigid insulation on the flat roof and then lay new paving slabs.
I have also used celotex insulation boards in a garden room in the uk created from an uninsulated garage that was effective:-

https://www.celotex.co.uk/products

Worldwatcher, try starting a new thread so that folk know what you are asking

Thanks for the advice. An insulation guy is coming over to give me a quotation. We'll look at both options.