We have a very shallow pitch and it is touch and go whether we can achieve enough head height with either a warm or a cold deck roof - even after lowering the first floor ceiling.
Someone has suggested using 144mm thick Structural Insulated Panels (SIPs) to make the roof and thereby saving approx 100mm. This would make all the difference to us, however, none of the loft companies we've approached have ever heard of them - which makes us nervous.
Does anyone have experience of using them? Are they OK. Are there any issues or problems with them - noise for example...?
Thanks!