In article ,
Grimly Curmudgeon wrote:
On Mon, 09 Jul 2012 10:54:18 +0100, "Dave Plowman (News)"
wrote:

Normal double glazing isn't a very good sound insulator as the gap is
too small. If you fit secondary glazing the thickness of the wall away
from the original you'll get very good results. Glass will be better
than plastic because it is denser - the thicker the better. And it
needs a good air seal all round.

Bingo all around, there. I rented a house on a busy main road -
double-glazed with secondary glazing of fairly thick glass in an
aluminium frame which could be removed for cleaning. The whole assembly
sat in a channel arrangement which allowed the halves to slide and
overlap. When shut, the noise was reduced to below the point of
normality - instead of a main road it was like being in a cul-de-sac. In
fact, it was so good at sealing, there was an extra wall powervent
fitted.

It's standard practice when using a non purpose built studio as a studio
for a TV series etc. Just get the original windows into decent repair
draught wise and add secondary glazing on the inside of the wall. Not
(relatively) expensive and gives a very worthwhile reduction in noise.
Standard double glazing doesn't as the gap is too small - but is ok for
heat insulation.

--
*Even a blind pig stumbles across an acorn now and again *

Dave Plowman London SW
To e-mail, change noise into sound.