How much loft insulation?

[Gavin77]

Hello everyone, 1st post.

Have recently moved house, and up in the loft is 75mm of fibreglass material. I think the modern regs call for 270mm, so im a fair bit short. My question is, how much difference will taking it up to 270mm make? is it worth doing? And if it is worth doing, what is the best stuff to use?

Thanks

Gavin

 

[kevnurse]

Insulation is only relevant if there is meant to be a significant temperature difference between the two sides of a partition. So, the answer to your question will depend on what temperature you want to have in the rooms directly below the roof void. Taking this to the extremes, to prove the point, if you want to live at outside air temperatures, you don't need any insulation at all. However, if you want 30 degrees centigrade in your upstairs bedroom through the night in winter you will need to fill your loft with a massive amount of wool, etc.

IMHO the regs apply only to new houses or substantially altered ones.

Put up there what you think you need, monitor the results this winter and then decide what to do. If you feel a significant temperature drop when you go up in the attic in the evenings, you have probably got it about right.