you are super-patient!!! :) :) thank you :) I'm so sorry but I do actually have a couple MORE thoughts!! argh! there are just so many different options.... and this is a bit of an all consuming puzzle to try to solve. here they are: 1) study could become main bathroom - leaving new Bed 4 as per plan since it is bigger & a better size for guests. in this option, some area could be stolen from the study to boost ensuite size - even if it just made the ensuite 1 full metre. Ideally not requiring study window to change. 2) WC could potentially be separate either within this space OR at the back of the old kitchen (allowing for the remaining, longish hall wall to be shorter again) oklouise you may think some of these ideas are not very workable & I'd be so glad for your feedback & comment (and anyone else's comments as well), it's really so incredibly helpful - unbelievably helpful - to have everyone's input. i'd love recommendations on which ideas & options might work best for that balance between function & budget

In all honesty, you are looking at a pretty expensive renovation so it is probably worthwhile getting some plans professionally done. The best alterations will be site specific, so will take into consideration the local climate, the path of the sun, where the best views are, anything blocking the sun anywhere, passive solar design, privacy from neighbours etc. It's just not possible to make a great design without all that information and it would be a real shame to spend tens or hundreds of thousands of dollars and not get the best result possible. Given that you haven't stated where you live, we don't even know whether North or South is the sunny side of the house, so it's impossible to suggest improvements! I'd strongly suggest taking your time figuring out exactly what you want to achieve and how much you are willing to spend to do so. Even with easy access under the house, shifting plumbing will not be cheap (from memory our plumber had the highest hourly rate of all our tradespeople when we renovated), so you want to be very certain that you're doing the right thing and will love the results. If you can possibly keep the same roofline, that will help reduce costs significantly. I'd also suggest using this as an opportunity to improve your house's performance, by insulating, improving the passive solar design, installing a heat recovery ventilation system, buying energy star appliances and LED lights etc. It's all the things that you won't see in the finished house that can have a major impact on how pleasant the house is to live in and how expensive it is to run, and they're easier to do when you're doing a major renovation anyway. Good luck!

OP, OKL's plan is better from an energy efficiency point of view than your plan (your plan wastes the northern aspect with bathrooms). But DON'T just flip OKL's plan, as the orientation would then be all wrong! It's important to get the orientation right, this will greatly effect the comfort of your home & your heating/cooling requirements (& hence your bills). Read this. It's all very useful, but maybe focus on the section about orientation first. http://yourhome.gov.au/passive-design Below are some generalisations. As has been requested, it would be nice to know your general location, as climates vary across our big country, so building requirements change. But generally, you want your living areas (& a large proportion of your glazing facing north). If possible, have a smaller portion of your glazing facing south & east, for cross ventilation, & try to eliminate western glazing. Bedrooms to the south & east (if they won't also fit in the north), & rarely used rooms, like garages, bathrooms & laundries to the west. Your verandah is south facing, good, as it won't shade your home in winter. Hopefully you have north facing eaves & they aren't too large. If they are the right size you'll get sun through your northern windows in winter, but the eaves will shade the house in summer, when the sun is higher in the sky. So can you knock out windows & doors wherever you want? Would be good to know where they are currently, the size of the verandah, the block dimensions & any other structures which will influence shading & privacy. I'd also be looking at some tiny house blogs/websites. 72sqm isn't tiny, but you really want an efficient house that works well, & you'll find some ingenious storage solutions that are used in tiny houses. Well designed built in storage is definitely very important in a small home. Can't see if it all fits now, while using the app on my phone. But I'd aim for something like this. The kitchen in the NE corner, running down the eastern wall (so you get good morning sun). An island bench for dining, separating the living area on the northern wall. Master in the NW corner, with the ensuite on the western wall (if it fits - important not to have the master bedroom window facing west). Minor bedrooms (& windows) on the south wall. Main bathroom or powder room somewhere on the southern wall, in the SW corner would be nice if it fits there. No idea is that all fits, just some ideas. If you're not fussed about an easy facing kitchen, you could flip this all, & have the kitchen in the NW corner, & the master in the NE corner. If you're taking off external or internal cladding, this is a good time to insulate you're walls. Also up insulation levels in the roof cavity of they're inadequate. It will greatly effect comfort, is quite cheap & the walls are very hard to do at other times. Edit: as I got the verandah location wrong, then added to my post.

anything is possible with enough money but with such a modest budget you might achieve the new bathroom and kitchen OR the extension but it would be difficult to achieve both at the same time but you haven't answered the questions??? what is the distance from the house to the back fence, what are all the floors, walls and roof built out of (ie inside and outside walls, concrete slab on ground, or is it a timber floor with crawl space underneath the house?? and NB where is north? ...what is the shape of the roof (hip or gable tiled roof or??) ...do you have an aerial photo of the roof like Google earth??...extending over the retaining wall shouldn't be a problem with proper cosntruction and there isn't anywhere else to go without losing the best outdoor area that has easy access to inside...the extra lengths of pipe isn't the biggest cost of new plumbing and a ventilating skylight will make a great light source for an internal bathroom...