Insulating new house

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phkk

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In the middle of building a new house and getting the inside ready for plastering. I'm very anxious that I insulate the house properly.....what would people recommend for the ceiling i.e-how much insulation?
Also what would you recommend for the attic? I heard somebody mention about adding a foil back plastering slab for external walls....could you please post me on any suggestions.
Thanking You
 
Building a storey and a half type house with two dormer windows to the front.....what do you think??
 
minimum insulation to meet current regs would be 100mm Polyurethane board (xtratherm rafterloc or similar) between the rafters / ceiling joists and slab out then on the ceilings with 47.5 composite plasterboard (35mm PU isulation backed onto 12.5mm plasterboard).......

and remember this spec is just to meet the minmum regs.
 
Thanks Syd....i really want to insulate the house as best i can and would be willing to spend extra few bob---after all,it will save me money in the long term....thinking of filling the cavity wall with pumped insulation....i've a four inch cavity with a 60mm foil Kingspan aeroboard sheet(builder told me this was sufficient but i have my doubts)....ive 9X2 joists in the ceiling,what sort of depth of fibreglass/fockwool/kingspan should i use...what are the best insulators?

any help from new house builders would be greatly appreciated
 
I am building a new 2 storey house with attic trusses so I have the use of all the attic space. I have used 100mm Xtratherm rigid board between the trusses following the pitch of the roof and slabbed with foil backed 12.5mm plasterboard.
I have used 100mm rockwool between the trusses which make up the floor of the attic and the ceiling of the 1st floor and slabbed the ceiling also with foil backed slabs.
I have also used 100mm rockwool between the joists that make up floor of 1st floor and ceiling of ground floor.
I used 100mm rockwool in the studding upstairs.
I used 75mm Xtratherm rigid board insulation in the cavity and a 32mm insulated slab on the inside walls.
I'm hoping I'll be snug as a bug in a rug.

Hope this helps
 
Nedtastic said:
I am building a new 2 storey house with attic trusses so I have the use of all the attic space.
1. I have used 100mm Xtratherm rigid board between the trusses following the pitch of the roof and slabbed with foil backed 12.5mm plasterboard.
2. I have used 100mm rockwool between the trusses which make up the floor of the attic and the ceiling of the 1st floor and slabbed the ceiling also with foil backed slabs.
I have also used 100mm rockwool between the joists that make up floor of 1st floor and ceiling of ground floor.
I used 100mm rockwool in the studding upstairs.
I used 75mm Xtratherm rigid board insulation in the cavity and a 32mm insulated slab on the inside walls.
I'm hoping I'll be snug as a bug in a rug.

Hope this helps
Click to expand...

ned its very possible that the two constructions highlighted above do not meet minimum regulations, especially the 100mm rockwool on the flat ceiling of the 1st floor.
By my calculations the 100mm rockwool would only give a u value of 0.39... and thats assuming a TC of 0.036 which i doubt it has.. it probably has a TC of 0.38-0.4.
You should have at least 300mm here, and you should have slabbed all the ceilings with 47.5 mm composite plasterboard.
Your walls should be fine but your ceilings are severely under insulated. Sorry!
 
Is it a good idea to put insulation in the ceiling of the ground floor?(unless the heating is zoned). I thought it was better to concentrate insulation in the floor of the attic and the external walls, and not to insulate internal floors and internal walls in order to keep an even heat in the house.
 
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sydthebeat said:
ned its very possible that the two constructions highlighted above do not meet minimum regulations, especially the 100mm rockwool on the flat ceiling of the 1st floor.
By my calculations the 100mm rockwool would only give a u value of 0.39... and thats assuming a TC of 0.036 which i doubt it has.. it probably has a TC of 0.38-0.4.
You should have at least 300mm here, and you should have slabbed all the ceilings with 47.5 mm composite plasterboard.
Your walls should be fine but your ceilings are severely under insulated. Sorry!
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If you have hollowcore between ground floor and 1st floor, would you need insulation too ?
 
the principles of energy efficiency and solar gains etc allow for as much free air flow within the building envelope. The idea of insulating floors is one i dont agree with, because you are basically accepting the fact that your house isnt insulated correctly.

You should aim to hold the heat within the building envelope once its generated, you should allow this heat to freely transmit through your house.
 
Nedtastic said:
I have used 100mm rockwool between the trusses which make up the floor of the attic and the ceiling of the 1st floor and slabbed the ceiling also with foil backed slabs.
I have also used 100mm rockwool between the joists that make up floor of 1st floor and ceiling of ground floor.
I used 100mm rockwool in the studding upstairs.
Click to expand...

Can you please explain why you choose rockwool for insulation? I thought it was more suited to sound insulation than heat insulation?
 
Syd ... I am only insulating between the ground floor and the first floor, not a flat roof. If I had to put in 300mm of rockwool between the joist, i'd have a hard time getting all the pipes and wiring in. As for putting the composite slab for the ceilings ... I don think so ... I have zoned heating so think it will work out ok. I guess I'll have to wait and see.
Bobby, I used rockwool between floors because it has better sound insulation properties than fibreglass and has similar thermal properties.
 
Nedtastic said:
Syd ... I am only insulating between the ground floor and the first floor, not a flat roof. If I had to put in 300mm of rockwool between the joist, i'd have a hard time getting all the pipes and wiring in. As for putting the composite slab for the ceilings ... I don think so ... I have zoned heating so think it will work out ok. I guess I'll have to wait and see.
Bobby, I used rockwool between floors because it has better sound insulation properties than fibreglass and has similar thermal properties.
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Ned, the point is that the construction doesnt conform with building regulations, which are law. So its not advisable to flout laws because it makes for easier plumbing. I assume you dont have an architect / engineer inspecting the build.
 
sydthebeat said:
the principles of energy efficiency and solar gains etc allow for as much free air flow within the building envelope. The idea of insulating floors is one i dont agree with, because you are basically accepting the fact that your house isnt insulated correctly.

You should aim to hold the heat within the building envelope once its generated, you should allow this heat to freely transmit through your house.
Click to expand...

That actually makes a lot of sense sydthebeat. Thanks.
 
Thanks a million Ned,your after giving me food for thought....your house will be definitely as snug as a bug after all the insulation....fair play to you,sounds like you know your stuff......somebody mentioned leaving out the insulation between ground and first floor,does anybody else think this is a good idea. im just slating the house at the moment,so havent much time to dwell on this issue.thanks
 
Phkk --- You dont really need to insulate between ground floor and upper floor. It helps from an acoustic perspective but from a thermal perspective, logically thinking it impedes heat from moving up through your ceiling to the first floor.

Syd .... Both myself and my very experienced engineer are more than happy with the level of insulation installed.Perhaps I didn't fully explain the design of the house which calls for more insulation in some areas and lessin others.
 
phkk said:
In the middle of building a new house and getting the inside ready for plastering. I'm very anxious that I insulate the house properly.....what would people recommend for the ceiling i.e-how much insulation?
Also what would you recommend for the attic? I heard somebody mention about adding a foil back plastering slab for external walls....could you please post me on any suggestions.
Thanking You
Click to expand...
To go back to your original question. If you have 9in joists in the attic (as indicated in a later post) I would fill them with 200mm fibreglass insulation, and lay another 200mm across this at right angles. I would use better quality fibreglass with a thermal conductivity of .40, instead of the .44 sold in DIY stores.
 
thanks ned and aeneas for your posts....quick question....wondering about not insulating the ceiling(ie in the ground floor up to the first floor)...surely if you're going to be spending most of your time in the kitchen/living room/sitting room,would it not be better to have the ceiling well insulated and curtail the transfer of heat,rather than lose it to upstairs??

just have my doubts
 
Nedtastic said:
Phkk --- You dont really need to insulate between ground floor and upper floor. It helps from an acoustic perspective but from a thermal perspective, logically thinking it impedes heat from moving up through your ceiling to the first floor.

Syd .... Both myself and my very experienced engineer are more than happy with the level of insulation installed.Perhaps I didn't fully explain the design of the house which calls for more insulation in some areas and lessin others.
Click to expand...

ned, im not one for questioning someone elses professionalism, but your attic insulation clearly doesnt comply with current building regulations by th edescription youve given above. If your engineer is willing to sign it off then perhaps he / she is not as up to speed as they should be.
 
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