Many factors can influence demo cost, such as the mentioned asbestos, but also site access, scale, complexity (is it full or partial demo?) and also if there is any potential value/salvageable aspects. The quicker the job the cheaper it will be. If it's deemed and easy crunch and level then it will be cheaper, if it's more fiddly with asbestos or possibly needing to work around/retain a portion of existing or if its at the back and harder to get machines in then that can increase the cost. It's not a simple flagfall cost of demolition. It's also pays to select an appropriate contractor for the particular scale/nature of the job, i.e. if you go for a company geared up for a larger job and yours is small then you won;t get much love.....sometimes it's a quicker/easier job for the builder to integrate it in with the contract and they simply allocate labour +bins and it ends up more efficient/cheaper ....it ultimately depends, it's horses for courses....if it's smaller scale you may be able to save by stripping some of the cosmetic stuff yourself and getting eh builder to finish of the messier/larger stuff and bring in specialist asbestos removers as required (no getting around that one, it is what it is)...otherwise shop around for a contractor appropriately scaled/suited to handle your particular job effectively/efficiently....best of luck :)

if the original asbestos walls are in good condition then they can re-be painted but if the walls are too damaged to be saved the asbestos needs to be removed by professionals and the cladding replaced, no reason you can't have different profiles on the front and sides as long as joints and corners are sealed properly but if you plan to install new windows it could be better to wait to repair sections of wall as the windows are replaced (i'd prefer to have all the roof and external walls in good condition and then do the internal work at leisure)... .modern fibrous cements are excellent ...we've just used flat fibrous cement with curved battens over joints and very happy with the results for our 50's house (there are several different brands available through the big hardware stores and research on line is much easier than trying to work out the variations in store) the gabled portico can be made as a separate structure or as a extension to the roof with valley gutters depending on placement of the solar panels (and/or solar panels can be moved)

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

Yep, it sure adds up doesn't it! It's a lot of money for perhaps not an equivalent amount of value gain. But it's not necessarily the builder's fault or issue here. Their pricing here is not surprising, but to clarify not sure how you can isolate the kitchen or what exactly does 30K mean? Is it joinery only, is it including fittings? Is the balcony upper or main level. The question is, is this actually the best way to spend your money? Considering how much you're spending, should you be considering getting proper value for the money and getting more for your money with potentially a different design?. Are you happy with the design? It's going to be super? Is it worth $400K to you for what you're going to get? If the answer's no then a design rethink is possibly in order. Where are you at in the design/doc process? have you used a drafty, designer, architect to help you with the process? What people often get quite wrong with renovation projects is the distribution of budget in regards to HOW it's being spent (you WILL spend it one way or the other), and it always comes back to the design/layout as to how well or not it's spent. Really need to see actual plans to be able to assess and comment further with more accuracy otherwise just speculating on in all. Depending upon your finishing decisions this sort if thing could easily nudge the $450K mark.