SIP's Construction Panels, anyone used them?

[villageidiot]

I am adding a flat roofed extension on top of a garage and considering using SIP panels , anybody have any experience of this construction method or any disadvantages that I may not be aware of ?

[villageidiot]

Yes , the intention would be to use it for the roof as well.

[villageidiot]

Cheers Moles

[villageidiot]

As this would be an extension to a 1980 built home it had been suggested that the insulation would be far superior to the existing property and this could cause problems ??, I plan to improve the insulation in the rest of the house but may struggle to get close to the performance of the SIP's. Another concern was that is does not appear to be widely used , is there a reason for this ? it sounds almost too good to be true with no drawbacks other than the insulation compatibility when used for extensions.
P.S. I have no building experience personally other than having a garage built which this extension will be above.

[villageidiot]

The garage is block built with insulated cavity and is currently warmer than the house which has a mansard roof with no insulation either above or to the sides . The only insulation is in the walls on ground floor which had polystyrene beads injected .

[villageidiot]

The garage is built with what looks like breeze block laid on its narrow side , the cavity looks to be about the same width as one block and is filled with rigid insulation board, the garage was built 6 years ago . It's just the house which has the bead insulation.

[villageidiot]

Ok, I've just measured , blocks are 100mm and overall width is 275mm inc render so cavity is probably actually about 50mm, the finish of the extension will be rendered to match existing garage and house . The attached computer generated photo shows what we are building , it is what you see above the wall to the left side , the