Building regulations for suspended floor insulation

WIAWSNB

stuart45 said:

For old floors it's 0.25 U value. 4 inches of Celotex between the joists will make this easily.

In which case ignore everything I've said before about not involving BC

Possibly.

battenburg88

stuart45 said:

For old floors it's 0.25 U value. 4 inches of Celotex between the joists will make this easily.

Do you mean that the required U value I would be required to meet is 0.25 U? I'd like to use natural insulation - probably hemp, but the void space below is quite deep so I think there will be space for this to be of sufficient depth to achieve that U value.

Edit - have just Googled yes, I think I can see that retrofit to an existing floor is 0.25 U.

Thanks all for coming back on this. 

We are also due to be insulating the roof of a lean-to utility room. For this the roof structure will be replaced with deeper joists to accommodate the insulation, and I was intending to submit a BC Notice for this as I'm clearly replacing more than 50% of the roof and would like this signed off. Potentially I could submit the notice at the same time and add the floor insulation to it.

Can anyone talk me through the BC Notice process? Is it just providing a simple description of the work that's being undertaken. I suppose I'll need to provide the U Value calculation, but AI might be able to help me with that!