3in cavity insulation

[dada]

am buildin a conservatory with 6 brick dwarf wall above dpc and 3 in cavity but want to insulate the cavity. am i right that i can / should only full fill it as a partial fill requires 50mm gap?
also, how low down does the insulation have to go - is it just above the dpc?
also does that meen air vents to vent the cavity are therefore worthless (below the dpc) or do they serve a purpose below the dpc?

 

[noseall]

insulating the cavity isn't gonna achieve an awful lot, but if it makes you feel better then full fill dritherm cavity batts will be best. at least it will reduce cold spots.

modern cavity walls are not vented.

 

[dada]

thanks. i appreciate the filled cavity dont need to be vented but underneath the dpc and insulation - isnt that worthwhile?
also does dritherm batts resist water ?

 

[noseall]

dritherm cavity batts do not wick water.