A sliding door is just a big window, and if correctly built in (check if the glass is the correct sized for the door if a bit old) with the correct sized lintels this should not be a big problem as the loads would be transferred to the sides, allowing the door to slide easily. Silicon spray (being a Yachtie were we use this stuff everywhere), we now use silicone spray on all our windows in our 1930 home and the windows glide across with one finger before they used to tilt when trying to open them. I would place the door head up to line up with the others and one thing you might consider is placing a window seat, (rebate the bottom channels into the window seat) and have the window seat in and out, place a cushion over the entire seat, should be fantastic and if the deck is built, than no balustrade is required. If it is a stacker slider, i would do the seat for the entire length. So instead of looking a bit funny they will think it was supposed to be like that. We should all think outside the square more often. RAM

Thank you so much for everyone's thoughts, it has honestly been very helpful. We are going to consider going right across the front of the house and over that problematic front door. Going to consider going across with the same space as we originally had going straight out. I'll keep everyone posted as I so appreciate all the help!!

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

The width of the laundry is 1.6m as my assumption is that bench/storage will be .6m with 1m for the path. The length of the laundry is about 3.5m and powder will be 1.2m. We like the idea of having the powder room there as it's quick access for visitors when we're entertaining. Where on the outer building would you suggest? By storage I was referring to linen mosley too, just in case there was some confusion.