When buying our renovator, the electrical inspector found the house had been earthed to the gas line instead of the water line. Plus other illegal wiring. The electrician would not leave the house until something else was rectified as well as the earth as the house at the time was rented. So glad we had that inspection as a few months after moving in we had a huge storm the house was hit by lightening then the high voltage lines fell across the house, we were home it was really scary but we had the whole place rewired before we moved in. Our neighbours behind said the house appeared to engulfed with a blue fireball. Our neighbours house did catch on fire. It would have been a different story for us if wiring was earthed to gas line.

Re the asbestos thing (and don't take this as pro advice...cos I aint) but if it looks like, quacks like it then it MIGHT be it. I thought I had asbestos walls (cos everyone said "it might be asbestos"...similar to some kid who may have been Jake Gyllenall saying to Arnie "it might be a toomore"). My walls were not asbestos. However I did find out that you can remove a certain square meterage of asbestos (depending on state boundaries) without have expert (very expensive) assistance (check the state rules). If it "might be" then be careful. As you are tiling over (therefor not cutting, grinding, messing about with?) then stay cool and tile to your tile glue's content!

Thanks everyone for your comments so far. Some great points have been made and I'm going to take each one of the away to have a think about. In the meantime, I've asked my draftsman to provide me all the measurements to existing and proposed so I can share it here as soon as I get them. Some more info: We're located in the northern suburbs of Melbourne. Our budget is approximately around the $200k...this is so we don't over capitalise on the property. We thought about building to one boundary because we are of the thinking that we need more width to achieve the space we want. As a guesstimate, I believe the block is 12m or so wide. Each lane way is approximately 1.5m (3m combined) which only leaves us with an internal width of 9m (minus walls). We chose to explore building to the eastern boundary because existing utilities such as hot water system, ducted heating are already setup there. Moving it to the western boundary would cost $$. The eastern laneway has nice new concrete paving and allows us to more easily access it from our carport.The other reason for potentially building to the east is because we're the 2nd last house on the street (near a corner). We get a bit of traffic on our street but more so on the street parallel the western wall. I thought it would be more peaceful moving the house away from the traffic and noise rather than towards it. Also, the addition of the dining area (connected to kitchen and alfresco) will give us a bit more privacy from the street (parallel to western wall) when we're out on the alfresco/deck. Just my thinking but happy to get some further feedback. We're happy to consider keeping the current building boundary if we can achieve the design we want etc. I've attached a few pictures of the existing low ceilings towards the back of the house. The pics show the ceiling from kitchen and towards the back door (curtains are closed). The ceiling is about 2.4m and you can see the exposed beams which makes the ceiling feel even lower. I'm only 1.6m and I can touch them with my finger tips if I try... Whether it's a full knock down or increasing the height of the roof, I think it's the one thing we're about improving/removing. Hope that's some more info for everyone to go off... Thanks again for everyone who has already replied and made some great points. Cheers

Hmm asbestos is insidious. It is not just about wearing ppe as the dust travels and settles elsewhere. That is why it costs so much to remove, they have to seal the area and then vacuum all dust and filter air (hepa filter)before reopening. One has to be careful not to disturb the asbestos, when in any doubt call in professionals, you only get one set of lungs.