one and half storey roof insulation

bb12

Registered User
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i've been reading loads about attic insulation, roof insulation etc but i still can't find the definitive answers to my question re: roof insulation in a one and half storey house.

what would be the standard spec for this in a new build? ie one that would satisfy current building standards?

my builder so far has offered me the choice of:

rafters: 150mm moy metac insulation plus 50mm thermawall slabs (38mm insulation + 12mm plasterboard)
or the option of using 100mm Kingspan Thermapitch TP10 as an alternative to the moy insulation

flat ceiling above rooms:150mm fibreglass between joists + 250mm laid over joists: total = 400mm

would this be enough for current building standards do you think?

also how is the insulation usually installed in one + half storeys? ie
is the norm to insulate the rafters from the eaves to the ceiling level of the upstairs rooms and then go across the ceiling joists? therefore the hatch area between the rafters and the rooms would also be insulated.

or is the square of the rooms just insulated upstairs ie. the outside of the room walls and the ceiling joists therefore having no insulation in the rafters and therefore the attic space in the hatches would not be insulated...

hopefully you can understand what i mean..or if anyone has a usefull link which would explain things clearly that would be great. i find the homebond manual useless for this.
 
Unless technology has imprved in recent time you should be aware that there is no benefit to double insulation. Insulation must be in one piece for true effectiveness.
Most builders dont realise this.
eg 150 + 50 = 150 and not 200.

I'm not sure what you trying for but avoid two layers of insulation spaced not that far apart.
eg if you seal/insulate the ceiling and then the attic you will get condensation dripping down like a tap from the trapped heat.

One layer only.
 
you shoul have it pumped with insulation. It is recycled newspaper. It is brilliant.
 
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