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Roof going on soon, I need to decide which insulation material/system to use. It is included in main contract but spec says “160mm K7 or equivalent to give 0.20 W/m2K”. I am aware this is min building regs so will be upgrading ... Builder wants to use Actis (Hybris and H Control) to save labour cost. Kind of like the H Control as a continuous layer but not at all sure about Hybris! I don’t want to push for PIR because I know it will end up with loads of gaps and I can’t be there to supervise. Would 200mm loft roll be easy enough to install from the underside, ie. self supporting until plaster boarded or would we need to use batts? I have plenty of space for insulation between and below rafters; raised tie trusses with 360mm rafters! What is the best balance of benefit vs cost?

Hi. We have opened the ceiling in our living room which had previously the ceiling in 2.4m height, with a normal plasterboard and 10cm mineral/glass fibre mix. The outside noise was less, but still noticeable. We now want to use the full space of the pitched roof to create a vaulted ceiling. At the moment the rafters have been strengthened and extended to 20cm depth, from which we have left a 5cm void below the felt under the concrete tiles for air ration and added 15 cm celotex insulation. I understand that celotex is great for the heat insulation and that we overreach building specs with the 15 cm, but that it does not do much against outside noise. As we live on a very busy road we wonder what would be the best way to insulate now the roof sound wise the best / economical way? Our builder wants to put additional 2cm wooden batons now under the rafters to account for uneven areas, not filled with anything and attach the sound plasterboard to them? Will this work, or just create an sound problem? Currently I am looking into two different thickness sized acoustic boards, depending on what is available on the market currently. I read about mass loaded vinyl which is quite expensive, and which seems to be often recommended to add in-between the 2 soundboard plasterboards. And in addition I read about resilient bars, where I wonder if they are ok with the weight of two heavy soundboards, and in addition if they are actually helpful against street noise, as this is rather an airborne noise instead of ground-born, , or am I wrong? Or are they rather for ceilings where a room is used above, and so not what I need? What would you recommend to keep out the road noise please? Kind regards Manfred

I am trying to work out general space requirements for a new build, and one area that i have some questions about is the thickness of the pitched roof. The two areas that look to determine how thick the roof needs to be is the structural requirements of the rafters and also the insulation required, of these the insulation is probably the thickest and the rafter thickness can be accommodated in it (100mm - 150mm) Having looked at a U-value calculator for 0.11 for roofs an indicative build up is as below https://www.uvalue-calculator.co.uk/calculator/pitched roof/insulation between and over rafters/unventilated/no sarking board/150mm/400mm/180/ This would probably be; - 13mm plasterboard - 180mm PIR insulation inc rafters - 38mm counter-batten - 25mm tile batten - circa 11mm clay roof tile - add 10mm for getting rafter and insulation thickness to line up So i am looking at a total of 277mm for total roof thickness, does that sound about right? Also why is the 38mm counter-batten in the suggested build up, and is it really required? Also how do you secure the battens though the insulation on top of the rafters? really long screws or something else? Thanks