Acoustic exterior insulation

I am interested in purchasing a duplex that has a brick front and the rest has cladding. I am concerned that we will have noise issues from the other half of the duplex Is there a product that can be added to the external walls prior to the cladding that would insulate from noise. I am a realist and am aware that you can not block out 100% of noise but would like to minimise. The builder has suggested a insulation rating of 2.1
I would appreciate and input. Gerri


Internally this might be worth looking into:


You might need to consider other noise transmission paths if you are concerned.

From our experience with a town house with a joining common wall noise can also travel or be drawn in through the roof space. A bit like a sound box on a guitar. So you may need to consider the ceiling too.

Some noises seem to travel around corners well, eg split air con unit fan noise seems to spread like a wave and comes back around the dividing wall (brick construction).

Two unexpected noises have been water pipe noise (hammer and whistling) when water flows next door for any reason. And foot steps on the timber stair treads which seems to come through the structure as a vibration. Both of these are probably due to design decisions that you cannot see or identify as a buyer or owner.

We’ve also noticed some noises reflect off the solid wall of a nearby building, which is more a location factor.

It may be impossible to limit all noise if you like the doors and windows open?


My immediate reaction was that if you are concerned pre-purchase just don’t do it.

That aside, I imagine there are many possible factors that might make it a tempting purchase none the less. My thought would be to ask the builder for 2 or 3 reference locations where they have effectively addressed the ‘through common wall’ noise issue and test it for yourself. Maybe not practical, but worth a shot …

@grahroll 's link looks very interesting, as is @mark_m 's reference to roof space - I’d imagine if you were using any kind of product from brick or normal insulation through to some super new-age thing, running it all the way to the roof-line would be a bare minimum, noting the other comments about noise paths as well.


There was an old story, possibly true or not. A prospective buyer indicated he was worried about noise from the adjoining unit and wanted to assure adequate acoustic insulation. The selling agent was happy to comply and went into the next unit to make noise (right he did) and returned to the client who had not heard any of it. Must have been really good acoustic treatment. I don’t remember if the sale completed in the story, or not. :smiley: