Hi All, I notice my terrace house has a common wall with neighbor having thickness of only 1 brick. Is this common in all terrace houses? What is the limitation for renovation on this wall if it just 1 brick wall (apart from hacking down the wall, obviously)? How about electrical wiring and piping?

You mean between the wall only have a brick, plus cement another few inch, right?

Yes, I'm having the smilar, but if you plan to renovate than you need to check whether the particular wall falled under your area or next door. If is next door than you may need to ensure your new build wall within your own area before your neighbooh complain...or he / she OK to share wall again.

put another layer of wall up. if you are willing.

its called party wall. if using 1 brick thickness its should have resilient insulation to prevent fire and noise from next house. if no insulation have to be at least 300mm. i suggest put up some insulation and plaster it.

Usually is 5.5"

Correct, the thickness includes brick (clay) + cement.

To be precise, the wall i mentioned is interior (living room and masterbathroom. I notice there are piping and wall sockets built in on these walls, is this mean that this particular areas are not covered with brick since my neighbors piping and wall sockets also occupied the other side of the wall (mirror image)? If i remove the piping or sockets will it cause crack to my neighbor's wall? I hope renovation sifus can share their experience. thanks

hard to say. As vibration may caused the wall have crack line...

yes common, 1brick width + plastering

Hmm, i thought they should be 2 brick thick between two seperating units of terrace house wall except for fencing wall. single brick only.

I think for party wall, 9" inch wall is only required if you are using cement sand brick. Clay bricks have higher fire rating, thus a 4.5" wall is sufficient (with plastering). As far as construction goes, contractors normally do not do an exact mirror image of the next unit. The will offset about 3-5" from the other unit if the party wall is 4.5" thick.

Offset what? If there is a bathroom, does that mean the washbasin and w.c. would be fixed 3.5" from the wall?

It's not up to the contractor, they have to follow the building plans.

Thanks all, looks like i need to avoid this common/party wall and built false wall to conceal piping and wiring. going to waste such precious floor space, but what to do.

Your contractor should be able to use a masonry cutter to cut a 2" trench into the wall without damaging the wall on the neighbour's side.
Cutting a 2" deep recess into a 6" thick wall shouldn't be a problem. Building another layer of wall to conceal the piping does not make sense.

My house also just 1 clay brick thickness.. And I can hear neighbours water pump (low frequency vibration sound) and water flowing through the pipe at high pressure (hissing sound).. and its quite noisy..

The pump seems to be coming from the attic through the plaster ceiling and also vibrating the walls...

Can someone advise how to solve this sound problem?

1 brick with plaster and paint is common for this wall.
By law, you should not alter this wall, because it serve as a fire wall.
But in actual, many people apply Nike theory "Just do it".