tvmo wrote:
I live in a Lovell-built semi-detached house, which was constructed in
2001.

A few months ago some smokers moved in next door. Since then we've
noticed the smell of smoke in the rooms that adjoin next doors house
(our kitchen, dining room and 3rd bedroom). I'm pretty sure that the
smoke isn't coming in through the windows.

Can anyone suggest where the smoke could be entering our property? In
addition is there any way I can confirm the smell we are experiencing
is indeed smoke?

I thought we had air leakage tests back in 2001 as part of the building
regs? If so, then you might have a claim under the NHBC 10 year
warranty. The leak could be due to shrinkage as the building dried out
since completion.

The leak probably means the party wall has settled and opened a
large-ish crack. The air is then getting past the plasterboard somehow.
If you can't see a crack in the wall then check any obvious openings
like sockets and where pipework passes through. Remove the socket and
seal the holes in the back box using mastic or tape depending on size.

Then you should take off the skirting board (and coving if you have it)
to see if there's a gap underneath. This could be easily blocked using a
combination of filler, expanding foam, draft proofing foam strip or
mastic depending on size. The leak could be completely out of sight,
i.e. in the floor or ceiling void, and then seeping into the room away
from the wall.

If you really can't find the source of the leaks (or the builder when
they honour the warranty) then you could always install a Positve Input
Ventillator (e.g. http://www.kiltox.co.uk/products/loftunit.htm) so the
leak always goes the other way....

-Antony