Can you put cavity insulation into a cavity with some insulation already present.

Question

The cavity in the outer house wall has some insulation attached to the bricks (blocks),polystyrene I think, but there is still a air gap.I was told by the workman who came to asses the job, that I could have this gap filled with teflon coated beads after he had spoken to his boss on the phone.When I phoned his boss to inquire when they would be coming to do the work ,he denied ever saying that.I am confused as to wether this is practical or not.I am getting the insulation on a government Warmfront grant so they choose the contractor and I dont have any choice.

Answer 1

You can add it yes, any reputable company should give you a cheap quote if insulation is already present. In a sense you are just topping up the cavity for more insulation so there should be no problems with it.

Some households qualify for free insulation (both cavity and loft) for free due to some governement  legislation (UK residence only). I believe it's subject to earnings.

Answer 2

do you still feel a breeze some where? Has your home been airsealed where you caulk all your mouldings, Insulate your basement perimeter and seal all holes that penatrate the floor from the basement? Have you installed outlet cover insulation strips? Hows your windows? Doors?

Have a real assesment of your home which includes a blower door test and a thermal camera.

Answer 3

you already have polysytrene, I wouldn't add the balls as this can be a conduit to allow prolonged rain to saturate the inner wall, leading to damp.

Answer 4

Filling the cavity involves contacting the Council because years ago, cowboys were causing more damage to the property by bridging the cavity with the wrong materials.

If you don't mind losing 2 or 3 inches of inner space, you could dot and dab thermal insulated plasterboards to the inner walls, choose the thickness of insulation you want.

Answer 5

You really need this air gap it allows water to drain to the bottom of the wall out to the weep holes, no gap moisture problems, you need to insulate the inside