Insulation Question

[Scoocher]

Is the following statement correct :


" The termal conductivity is the same on insulation thicknesses between 25 and 44mm. The thermal performance of the product kicks in only when >45mm, below this the comparison is the same as standard polyiso"

and if so is there any benefit in using a 40+9.5 insulated slab as opposed to a 38+12.5 slab or any other slab with insulation thickness between 25 and 44 for that matter?

 

[galwaytt]

Short answer is no, there isn't. The conductivity of the two thickness' of plasterboard is also the same at those thickness'.

I wonder about availability of that 40+9.5 - the 38+12.5 is far more common. And, the 12.5mm board would be more robust for house use (hanging things, etc).

That behaviour is common across XPS too. It doesn't automatically increase it's value for every mm of thickness.

 

[sydthebeat]

" The termal conductivity is the same on insulation thicknesses between 25 and 44mm.

thats statement is correct because thermal conductivity does not depend on thickness. Every material has a thermal condictivity. Thermal conductivity is a rate (of heat loss). A U Value is the measurement of heat loss when thickness is taken into account.

The thermal performance of the product kicks in only when >45mm, below this the comparison is the same as standard polyiso"

That statement is open for debate. What product is it referring to? Generally it would appear to be incorrect as any thickness of any material have an insulating effect... but obviously the thicker the thickness and the lower the thermal conductivity the better for insulating against heat loss.

is there any benefit in using a 40+9.5 insulated slab as opposed to a 38+12.5 slab or any other slab with insulation thickness between 25 and 44 for that matter?

assuming you are referring to "cosy board" type product....
the 2 mm of the insulation material would obviously give better insulation than the 2 mm of the plaster board. The question is actually if a 9.5mm plasterboard can hold up the same fittings than a 12.5mm board. I wouldnt think so.

edit: snap galwaytt

 

[galwaytt]

edit: snap galwaytt

touché