Our next door neighbours are having a baby soon. The previous neighbours had two kids and the noise could get very bad, so we are looking into getting sound insulation for our two main bedrooms.
Weve got some quotes, but just thought Id ask if anyone has had this done and if so, what the results have been? Thanks
Wall construction and method used can have varying results.
What method of sound insulation are the people you have quotes from proposing to use?
I used to test and advise on the sound insulation of new and converted properties for building regs. It's very easy to get wrong.
The main issue which will hamper performance is sound flanking around the extra partition/structure that's put in. The areas of weakness are under-floor voids, ceiling voids and the cavities in cavity walls. Also unless the existing wall is stripped back to bare brick, you won't know if there holes and gaps in it too.
To do a good job you'd be looking for someone who advises continuing any new partition into floor and ceiling voids or beefing up* the existing ceiling, floor and perpendicular walls too (almost building a room within a room). In the latter case, sound can still flank past the new partition but is stopped by the beefed up walls, ceiling etc.
To the layman this all sounds a bit overkill, which is why about 60% of the house to flat conversions we used to test in London failed building regs.....
The best solution would be a new partition that goes from ground floor level up into the attic, and continues through the ceiling voids. This partition would have to be isolated from the existing party wall, by either being separate or using some sort of isolating coupler. First you would also strip back and make good the existing wall, with render/plaster to fill any gaps. The joist orientation will have a bearing on this too. A room within a room approach might be better if the joists hang off the party wall.
An acoustic consultant** is the person to advise on this and outside of them avoid anyone selling a specific product.
*the floor can be beefed up with a floating floor, ie isolating coupling between the joists and floorboards. Extra layers of plasterboard might be all that's needed on the ceiling and perpendicular walls. I say that cautiously
**I used to be one.
It's a very tricky thing to do correctly as said above.
You can't just slap on some sound proof plasterboard, read and quiz there quotes to find out what they suggest to do.