Insulation query

foxfordbuild

As part of my timberframe quote I requested a price for insulation as follows :

External walls - 100mm Kingspan
Roof - 200mm Kingspan
Floor - 50mm Kingspan
Internal walls - 100mm \ 150mm rockwool

Would this be a decent choice ?

Jimbo

50mm for the floor is a little tight considering you putting 100mm in the walls

Mellor

The floor needs to be more insulated than the walls, go closer to 100, 100, 200

Slates

Mellor wrote: »

The floor needs to be more insulated than the walls, go closer to 100, 100, 200

Why is that ? is it not worked out by area vs perimeter ?

foxfordbuild

Thanks for the advice, if I double the floor insulation to 100mm, what sort of u value should I expect ?

Thanks

Mark

Jimbo

Depending on the perimeter/area ratio of your house, in a standard ground supported concrete floor, you'll be looking at a u-value of about 0.16 which is pretty good by any standard

sydthebeat

foxfordbuild wrote: »

As part of my timberframe quote I requested a price for insulation as follows :

External walls - 100mm Kingspan
Roof - 200mm Kingspan
Floor - 50mm Kingspan
Internal walls - 100mm \ 150mm rockwool

Would this be a decent choice ?

have you compared the difference between this spec timber frame and a TEK house???? there may be a smal enough difference to make it worth your while getting a TEK system, which is a much better build system....

Jimbo

sydthebeat wrote: »

have you compared the difference between this spec timber frame and a TEK house???? there may be a smal enough difference to make it worth your while getting a TEK system, which is a much better build system....

What deparment of Kingspan do you work in?

sydthebeat

jimbo78 wrote: »

What deparment of Kingspan do you work in?

don't worry i haven't sold my soul yet.....

Im making the point that if the OP is planning on putting 100mm kingspan in the walls, why not fork out the difference for a 140mm TEK system which is immeasurably a better system,,... designed to be very airtight and much more structurally solid than a timber frame.

Jimbo

Sounds impressive.. must look into that

foxfordbuild

sydthebeat wrote: »

have you compared the difference between this spec timber frame and a TEK house???? there may be a smal enough difference to make it worth your while getting a TEK system, which is a much better build system....

Got a quote for the Tek system which would be 74k plus VAT so big difference in price, my original spec plus the amendments for the insulation come to 48k including VAT

250882

Just a thought but 100mm between the studs will leave the timber as a cold bridge, I'd dryline inside aswell, and 200mm kingspan in the roof will leave you with huge rafters(min 250mm!!!!) if on the slope and if above ceiling joists I would reccomend 150mm mineral wool between joists and 150 laid perpendicular on top, this will stop thermal bridging through the timber and it works out easier and cheaper with roughly the same u-value.

DLBuild

I have wondered about this. If laying 150 mm mineral wool/glass wool fibre between joists and then another quantity across the top of the joists how would you then lay flooring if you intended to use your attic space?

sydthebeat

DLBuild wrote: »

I have wondered about this. If laying 150 mm mineral wool/glass wool fibre between joists and then another quantity across the top of the joists how would you then lay flooring if you intended to use your attic space?

you need to incorporate extra joists running either perpendicular or on top of the existing joists to create a floor 300mm thick.
If 300mm of quilted insulation is compressed to, say, 150mm you only get the performance of 150mm quilted.. if even that.
This is why insulation backed plasterboard should become the norm for ceiling finishes.

ardara1

DLBuild wrote: »

I have wondered about this. If laying 150 mm mineral wool/glass wool fibre between joists and then another quantity across the top of the joists how would you then lay flooring if you intended to use your attic space?

ALternatively layer the underside of the joists with 50mm of polyurathane board.
Regs says that access walk ways should be constructed to reach tanks etc. - wait 'till new regs kick in! 500mm fibre?

sydthebeat

ardara1 wrote: »

ALternatively layer the underside of the joists with 50mm of polyurathane board.
Regs says that access walk ways should be constructed to reach tanks etc. - wait 'till new regs kick in! 500mm fibre?

without attempting to go off topic.. but dont the new regs actually revise up the ceiling regs???? will it be possible to comply with less insulation than is required now??

DLBuild

Sorry if I appear to not have much of a clue here but I'm just starting out and trying to learn as much as possible as quick as possible. Seems like a big job to run extra joists simply for the purpose of insulation housing and this doesn't seem to address the thermal bridging issues mentioned here. Maybe the insualation on the underside of the joists is the way to go. I'm building a 2 storey house with underfloor heating and want to use the attic space(lots of it so why not). So far i'm considering 100mm Kingspan in ground floor, 60mm in 100mm cavity wall, drylining exterior walls with 25mm backed plasterboard. I'd appreciate any helpful suggestions on what to use and where. I've been told glass wool fibre or similar is the most commonly adopted approach ot ceiling insulation between joists in ceilings between 1st floor and attic space. Would 150 mm of this between joists combined with insulation backed plasterboard on ceilings be sensible? Is there somewhere in particular I can view building regs to make sure i'm meeting them at least if not beating them? I believe I also need insulation on the slabbed floor between ground and 1st floor underneath UFH pipes. Thanks a million.

AckwelFoley

sydthebeat wrote: »

without attempting to go off topic.. but dont the new regs actually revise up the ceiling regs???? will it be possible to comply with less insulation than is required now??

I think people are too focused on merely complying rather than optimising.

Insulation is extremely important, it determines the heatloss and ultimately the energy consumption of the home.

sydthebeat

snyper wrote: »

I think people are too focused on merely complying rather than optimising.

Insulation is extremely important, it determines the heatloss and ultimately the energy consumption of the home.

i was just responding to ardara1's '500mm fibre' question.... the new regs are controversial..... thats all i was pointing out...

i completely agree that 'optimising' is the key.... clients / builders look at the regs as a 'target' rather than a 'minimum'.

AckwelFoley

sydthebeat wrote: »

i completely agree that 'optimising' is the key.... clients / builders look at the regs as a 'target' rather than a 'minimum'.

Yes, i made the mistake on my first house.

Now id rather spend an extra 5 - 8 K on top of the estimated insulation costs because it is worth it

ardara1

sydthebeat wrote: »

without attempting to go off topic.. but dont the new regs actually revise up the ceiling regs???? will it be possible to comply with less insulation than is required now??

Hi Syd = in the 9 house types used as guinea pigs and brought up to comply withthe new Part L All roofs were improved to 0.11 !!!!!

ardara1

sydthebeat wrote: »

without attempting to go off topic.. but dont the new regs actually revise up the ceiling regs???? will it be possible to comply with less insulation than is required now??

Hi Syd - the DOE took 9 house types to bring them up to the new standards - all had roof U-values of 0.11 !!!! - see the Part L posting further down