To insulate first floor void, or not?

[benben5555]

I'm trying to decide if to insulate the first floor floor void or not. I don't believe it is  building reg requirement (feel free to correct me). 

 

Benefits are reduced sound transmission, and stops so much heat transfering upstairs?

 

Problems I see are the void is full of services, cost, time and getting the insulation to be continuous and not fall out from between the joists.

 

Any thoughts?

[TonyT]

Insulate first then run services?

 

Sound insulation?

 

[ProDave]

I thought sound insulation was a building regs requirement.

[Big Jimbo]

@ProDave It is.

[JohnMo]

Yep rockwool type material - not PIR, otherwise you will hear every noise from above. Plus as said noise is covered in building regs.

[Conor]

You only need 50, it's not that expensive and easy to fit if you use the non itchy recycled stuff.

[benben5555]

I just checked Part E. It needs 100mm mineral wool.

 

What's the best way to do this? Position pipes and cables in the top of the floor void, then push the mineral wool in the gaps between the joists before plasterboard? 

 

Wool rolls are the cheapest, but I can see it falling out as its not very rigid.

[Kelvin]

20 hours ago, benben5555 said:

I'm trying to decide if to insulate the first floor floor void or not. I don't believe it is  building reg requirement (feel free to correct me). 

 

Benefits are reduced sound transmission, and stops so much heat transfering upstairs?

 

Problems I see are the void is full of services, cost, time and getting the insulation to be continuous and not fall out from between the joists.

 

Any thoughts?

 

I’m doing exactly this as we speak. It’s a building reg as far I understand it. Even if it wasn’t I’d be doing it anyway. In the grand scheme of things it’s not a huge expense. I’ve put all above the cables and between all the webs of the joists. 
 

If you cut slightly bigger than the hole your filling it stays in. 

Edited September 5, 2023 by Kelvin