Help needed on where to put insulation

[tommyleestaples]

Hi all,

 

I am about to extend my house and plan to insulate it as it seems the ideal time to do it. 

 

The ground floor is and the new parts will be suspended timber flooring with quite a void underneath. I plan to insulate between the joists.

 

The loft will be insulated at rafter level so my question is what do I do with the ceiling void on ground floor and first floor. I have heard some people insulate between the floors but from what I read online if the floor on ground level and the rafters of the loft are insulated then you leave the floors. I am not sure what is right to it would be great to see what you guys suggest. 

[JohnMo]

1 hour ago, tommyleestaples said:

I am not sure what is right to it would be great to see what you guys suggest

Step back and think. Why do I insulate? To keep warm inside the house and the cold outside. 

 

You insulate to form an envelope without gaps around the whole building. Any insulation inside that envelope isn't for thermal reasons it's for noise control.

[joe90]

Any insulation in ground floor ceiling is for sound.

[SteamyTea]

15 minutes ago, joe90 said:

Any insulation in ground floor ceiling is for sound.

And for temperature control i.e. keeping bedrooms a bit cooler.

 

Most unmodified, older, houses could save 30% of the space heating usage with better thermal control.

It is a hard sell to most of the public that like to think that heating is either fully on, or fully off, with nothing in-between.

[tommyleestaples]

Thank you for the advice. So we are looking at something like this.

[IGP]

This is exactly what I did, though we have insulation at joist level in the loft. 
 

Did the ecological building systems approach for the ground floor suspended timber floors which has been amazing.

 

https://www.ecologicalbuildingsystems.com/post/best-practice-approach-insulating-suspended-timber-floors

Done acoustic insulation between the floors too.

 

Also done MVHR too, replaced all radiators calculated for 40c flow temperature ready for heat pump. 

[haythorn_1]

On 09/07/2024 at 09:48, tommyleestaples said:

Thank you for the advice. So we are looking at something like this.

 

Did you end up doing this?

 

I'm at a similar point and trying to decide if it's worth putting acoustic insulation in the attic floor joists. The attic will just be used for storage and MVHR, but maybe the insulation will prevent noise being transferred between bedrooms on the first floor over the walls?