cavity insulation

| I have just got a quote for "rock wool" cavity insulation. It is the sort | that is pumped into the cavity. As any one had problems with it coming into | the house through holes in the inside wall, say if soil pipes have not been | sealed after fitting. I friend says it is a problem with some types of | insulation, but not sure about rock wool.

I had foam put in many years ago without problems, except lumps of foam in the underdrawing, where the cavity was no sealed.

Thanks Dave. Do think this "rock wool" type will be foam? I should have checked when guy came for quote but I was not at home. Neil

| Thanks Dave. Do think this "rock wool" type will be foam? I should have | checked when guy came for quote but I was not at home.

No Rock wool, which I looked into at the time, was bits of fluffy stuff which they blow through a pipe into the cavity Pics at

Now if rock wool would have fallen into my underdrawing I do not know. because I do not know how well it sticks together in lumps. Foam is partially set by the time it gets to a hole, so only a smallish amount can escape.

I only mentioned it because the foam definitely came out.

Only old houses need cavity insulation, because the new ones have insulating board in the cavity.

We had no problems at all in our70 year old house.

Mary

Did you use rock wool pumped into the cavity. Neil

Hi

Had Rockwell insulation done a couple of years ago. Took just over 2 hrs for a 1930's semi. Had no problems with leakage in the house. A hole was in the old coal shed where wires had been taken out to the garage, that was the only place I saw a few traces.

Rob

Had rock wool type insulation installed in our 50's house - its in a pellet form that expands when pumped into cavity - made our house feel warmer and saving on fuel bill. Have you checked for subsidies? When ours was installed the cost was 175GBP for 4 bed detached the cost was subsidised by electricity board. I believe these subsidies are still available

Phil

Yes.

Pellets are usually just 'polystyrene' type balls that fill the gap - never heard of ones that expand once inside the cavity. Rock wool comes in large bales, is more like a mix between cotton wool and fibreglass, and gets chopped up in a machine before being blown into the cavity.

Since it's blown in under a certain pressure to ensure it fills the cavity properly, you might get some leakage as it it being blown in, but not afterwards. I had a slight leak into the loft where there was a gap in the mortar between blocks the inner leaf. My dad had the wet foam type put in 25 years ago, and still has large 'balls' of set foam in his loft where it leaked in.

I wonder whether there is any posibillity of the fluffy stuff settling over the years.

After all, our dry-powder fire extinguiser has to be "un-settled" every year then again, I suppose there are wall-ties in the cavity giving some load bearing surface to the filling.