Calculating benefit of insulation
Discussion
Bit of a maths question this, maybe!
Ok, live in a barn conversation and we noticed the insulation was poorly done. I’ve got myself a thermal imaging camera and improved some test areas. Now, the ceiling I re-insulated surface temperature has risen by 3 degrees compared to the surrounding surface.
If the room temp is 21 degrees and the normal surface temperature is 12, increasing the temp to 15 will obviously lower the losses. Based on our fuel consumption it must be possible to calculate the payback of insulating the entire roof.
Do I assume I’ve improved things by 25% (12 to 15). Calculations prove a new R (or was it U) of 3 x insulation improvement.
Help!
Ok, live in a barn conversation and we noticed the insulation was poorly done. I’ve got myself a thermal imaging camera and improved some test areas. Now, the ceiling I re-insulated surface temperature has risen by 3 degrees compared to the surrounding surface.
If the room temp is 21 degrees and the normal surface temperature is 12, increasing the temp to 15 will obviously lower the losses. Based on our fuel consumption it must be possible to calculate the payback of insulating the entire roof.
Do I assume I’ve improved things by 25% (12 to 15). Calculations prove a new R (or was it U) of 3 x insulation improvement.
Help!
Hmmm. Knew it wouldn't be easy....
Basically my 'problem' is that whoever insulated my property during renovations used a 'foil based multi layered' superquilt from YBS insulation. Now despite them attaching instructions to every roll - overlap and tape joints, the idiots who installed it forgot the tape, so wind basically blows all the warm air out, not that this was immediately obvious because the plasterboard covers everything up.
Now, rather than rip the house to pieces I've been drilling 8mm holes and filling the area between the plasterboard and the 'leaky quilt' with expanding foam.
This appears to massively improve things by stopping the draft behind the plasterboard and moving us from air gap insulation to 150mm of semi rigid foam.
Basically my 'problem' is that whoever insulated my property during renovations used a 'foil based multi layered' superquilt from YBS insulation. Now despite them attaching instructions to every roll - overlap and tape joints, the idiots who installed it forgot the tape, so wind basically blows all the warm air out, not that this was immediately obvious because the plasterboard covers everything up.
Now, rather than rip the house to pieces I've been drilling 8mm holes and filling the area between the plasterboard and the 'leaky quilt' with expanding foam.
This appears to massively improve things by stopping the draft behind the plasterboard and moving us from air gap insulation to 150mm of semi rigid foam.
The vaulted ceiling/ roof build is:
Plasterboard
Rafter creating 3-4 inch air gap
Plywood
Batten
Foil
Batten
Membrane
Batten
Tiles
The original problem was that the wall insulation wasn’t taken up (as plans show it should have been) to the plywood under the roof.
This error was causing wind to blow behind the plasterboard!
This has now been rectified by foaming the wall / roof joint.
Im either going to fill the air gap cavity with foam or use insulated plasterboard (much more expensive) and re board the ceiling/roof (it’s vaulted).
Plasterboard
Rafter creating 3-4 inch air gap
Plywood
Batten
Foil
Batten
Membrane
Batten
Tiles
The original problem was that the wall insulation wasn’t taken up (as plans show it should have been) to the plywood under the roof.
This error was causing wind to blow behind the plasterboard!
This has now been rectified by foaming the wall / roof joint.
Im either going to fill the air gap cavity with foam or use insulated plasterboard (much more expensive) and re board the ceiling/roof (it’s vaulted).
Thanks for all of the helpful replies and info. fwiw we've never seen as much as a drop of condensation on any windows. House has underfloor heating and fully air conditioned / dehumidified as well as fresh air heat exchanger (during the installation of AC is when I discovered all of the issues)
Little Lofty said:
I used Tri Iso multi foil on a few lofts around 12 years ago. One in particular was for a mate, he still raves about how warm the loft rooms are and that he virtually never heats them. I also remember revisiting one of the lofts on a very hot summers day (rare up here 
) and was surprised at how cool the room was, my loft at home had been very warm. I stopped using it when building control lost confidence in it. It didn’t save a lot of money but did save time, it also didn’t really improve on headroom as the rafters always had to be beefed up anyway. It was much easier to handle and store though.
I bet you taped the joints! ) and was surprised at how cool the room was, my loft at home had been very warm. I stopped using it when building control lost confidence in it. It didn’t save a lot of money but did save time, it also didn’t really improve on headroom as the rafters always had to be beefed up anyway. It was much easier to handle and store though.Gassing Station | Homes, Gardens and DIY | Top of Page | What's New | My Stuff