Blocking up part of the window. What needs to be filled in the new cavity

lokz

Hello All, 

Currently doing a integral garage conversion. 

Got this garage window blocked up to half last week. A new window will be fitted for the rest half. What needs to be filled in this cavity. This wall is the external wall of the house as this is the integral garage. (attached some pics)

I see a small sheet in between the two walls currently. Not sure what it is .

If it is a garage in-fill door, I understand that it will be sheet of cellotex. 

what does a  Building inspector inspects when he looks at blocking half of the window. 

Thanks. 

stuart45

You can use a cavity closer. Is a builder doing the job, or is it DIY?

lokz

stuart45 said:

You can use a cavity closer. Is a builder doing the job, or is it DIY?

Thanks. Should the new cavity be empty or should it fill it with anything. The brickie did the above job, I am getting the regular handyman to make it ready for it be fixed with a window by the window installer. So i need to let the handyman know exactly what needs to be done. 

stuart45

Have you had any plans drawn up?  Modern cavities are normally insulated.

lokz

stuart45 said:

Have you had any plans drawn up?  Modern cavities are normally insulated.

No Plans. Just building notice application. 

stuart45

The original cavity might not have been insulated as it was a garage, but will now need to meet the requires U value for a conversion. You need to talk to Building control about how you are going to meet these values. It's possible to have cavities filled, or insulated plasterboard.

casper_gutman

Is there any sign that the existing cavity has any insulation? Nothing much is visible in the photos, and as stuart says there might well have been nothing as it's just a garage. Now that you'll have to bring it up to habitable standard, you'll presumably need to add a fair bit of insulation. This may well exceed what you could get in the cavity, so some internal insulation might be needed. If you need to add a layer of insulation internally anyway perhaps you might as well add all the insulation there and leave the cavity empty, especially since filling cavities can lead to issues with damp and risks cold spots if loose fill insulation fails to reach all areas.

lokz

@stuart45 @casper_gutman, Thanks both , that makes more sense now. 

The original cavities when built were empty and the previous owners have done cavity insulation in 2006 . I remember my brickie showing the cotton like white substance when he removed few bricks, between the brick and the block. 

I have planned to do the internal insulation anyway (for the building regs as well as to keep my habitable room much warmer)  and will leave this cavity empty and close it with cavity closers.