Fibreglass V Rockwool

reilig

I'm going to buy my house insulation today. My Brother in law (my builder) recons that 100m of fibreglass will be good enough for sound proofing my ceiling / second floor. He says that we will put it between the joists as we put up the slabs. I already have ply on the first floor. My hardware is pushing me to buy rockwool flexi. But its almost twice the price of the fibreglass. My brother in law did his own house with the fibreglass 7 years ago and it seems to have done a good enough job at sound proofing between the ground and first floor.

So what I'm asking is, is it worth my while spending the extra money on the rockwool or should I just stick with fibreglass as advised?

Or has anyone got any cheaper alternatives?

Any advice would be appreciated.

Dan

RKQ

Rockwool isn't itchy on the skin like fibre glass and is probably better if fitted vertically in stud partitions as its less likely to sag.
Rockwool is less likely to burn in a fire, so it has better fire resistance qualities than fibre glass.

In a horizontal position (between ceiling joist) I'd stick to fibre glass.:D

reilig

RKQ wrote: »

Rockwool isn't itchy on the skin like fibre glass and is probably better if fitted vertically in stud partitions as its less likely to sag.
Rockwool is less likely to burn in a fire, so it has better fire resistance qualities than fibre glass.

In a horizontal position (between ceiling joist) I'd stick to fibre glass.:D

Thanks, I appreciate your input. Yes, I have decided to put the rockwool flexi in the stud walls - for ease of use. But the ceilings I was unsure of.

Stuxnet

fibreglass is more of a heat insulate & rockwool mostly used for sound
you'll see 100mm of rockwool is a lot denser then 100mm of fibreglass

reilig

BOBBY wrote: »

fibreglass is more of a heat insulate & rockwool mostly used for sound
you'll see 100mm of rockwool is a lot denser then 100mm of fibreglass

Thanks for the advice guy's. I bought my insulation for the house on saturday last. Rockwool for the stud walls and ceilings and fibreglass for the attic. I struck a good deal with by building supplier which saw me get Quinn Radiators at 50% off list price and 4 inch rockwool at the same price per metre as 4 inch Fibreglass. I spent a couple of €000 with them on saturday wich gave me good bargaining leverage. Had priced all the stuff in the North, but ended up getting it just as cheap from my own building supplier with free delivery.

yop

How much is a roll of Rockwool and roughly what area would it cover?