best insualtion for 50mm cavity, internal solid brick wall

[jimAuk]

Hi

We have a large bay window (5.5m x 2.5 on each side) and is about 0.7m high, double glazed all above.

Currently the only heating in this room (apart from a multi fuel burner) is just a small skirting type fin radiator.

We have sized the required BTU for 2 new double panel, double convector rads (and boiler checked for spec), so my plan was to use T off the fin rad pies at the required points for the two new rads. (possibly removing the fins?)

And to save burring the pipes + insulate the solid double brick, I was first going to line the wall with reflective foil and then build a 50mm deep stud wall and the plaster board over. (+ also alow for rad fixing)

But my question is for the 50mm cavity what is the best infill material? Things that spring to mind for me are Rockwool, polystyrene or the celtoex.

Thanks in Advance.

 

[guidedog]

If you cut tee's straight into the skirting board pipe you will then have rads on a one pipe system which is not efficient. You need to cut pipe at both ends and connect the right hand pipe to the right hand side of the rads using a tee piece doing the same on the left connecting the left side to the left hand pipe.
Regards the insulation you can purchase 2" board insulation that designed for that purpose

 

[jimAuk]

If you cut tee's straight into the skirting board pipe you will then have rads on a one pipe system which is not efficient. You need to cut pipe at both ends and connect the right hand pipe to the right hand side of the rads using a tee piece doing the same on the left connecting the left side to the left hand pipe.
Regards the insulation you can purchase 2" board insulation that designed for that purpose

I am well aware of it been on a loop system and my T's would be one on the flow and one on the return!