Yet another insulation query...........

[JDLDIY]

The joists in my loft are 100mm deep and are at 19" centres which gives 41 - 43cm gaps to be filled with insulation. Currently I have none.

I was going to get the space blanket from B&Q as it just seems so easy to lay, but it's width is only 37cm. Will this mean it's a bad idea, I mean will the gap (4-5cm)make that much difference? I can't be bothered to cross batten other joists over the top to increase the insulation depth - so i was just going to lay some boards over the insulation, although it will compress it down, where I need them.

What do you think?

 

[noseall]

i would lay the thick quilt type myself, but i'm old fashioned.

it may not seem important but quilted insulation does offer a modicum of sound travel resistance too. if you have ringed doves cooing on your ridge tiles you will appreciate this.

 

[JDLDIY]

Hi there noseall, the space blanket is quilted insulation but bagged up and with a foil side which goes face up. Just doesn't quite fill the 41-43cm gap I have. What widths does insulation normally come in?

 

[noseall]

41-43cm gap I have.

that's a pretty BIG gap.

EDIT.
thought you were referring to joist depth.

 

[noseall]

combi-roll insulation packs are ready perforated that are designed to fit into joist gaps associated with 400, 450 and 600 centered joists.

 

[JDLDIY]

so you then just rip them do you? Who makes these combi rolls?

 

[noseall]

so you then just rip them do you?

yup. there are pre-designated lines drawn on the packaging. cot through the packaging with a sharp knife then pull apart.