we wanted to insulate our verandah roof as well as allowing light through lazerlite panels so we lined under the verandah with corrugated zincaluume with blanket insulation and then put corrugated lazerlite under the lazerlite panels: a double layer of lazerlite and a neat ceiling and looks fabulous

I'm going to assume that when you say the rear of the house is east, that's the kitchen! If so then you have a great northern aspect across your kitchen and living areas. I would think that opening those areas into a large space would be great especially considering your limited budget however make sure you adequately eave or screen those windows for summer. Come winter it will be lovely and warm and with the right eaves, lovely and cool for summer. Considering you have a 4th bedroom/study you can also use that as a separate kids space when you have guests so you don't necessarily need two living areas. As for the bathroom unless you have a second toilet somewhere don't make it one big space. We have this problem at the moment and you really don't want to have a shower while your kids doing their morning poo. Not to mention the fights when one of them is in the shower and anyone else has to go.

Please excuse this quick dodgy recolour , but just wanted to show the difference some kind of contrast would add to the effect of the exterior. Whether it is painting the roof (because it is such a big part of the facade), rendering or painting the bricks or refinishing the windows in black or white, something to let the architectural features is the key to sprucing up the outside. I think someone mentioned adding a verandah too. That would depend on how much light already comes through the front. I can imagine one of the windows on the side being transformed into french doors leading to a lovely flagstoned garden. I love the black and white interior photos someone posted above too. anything to bring some contrast to all that mud coloured brick. What an inspiring project to have ahead of you, so many possibilities! I wish this were my little house :)))

The issue is not so much the cladding material, but rather the articulation of the extended building form. This could be a simultaneously exciting, interesting and sympathetic extension utilising shingle cladding that wouldn't necessarily reference Hampton's. If there's anything too Hamptons going on here it's the small proportioned windows with the external shutters that give it a bit of a "dollhouse"popped on the top look. You've got a stunning beautiful home frontage, but the extension form is kind of sticking out/up the back and the fenestration looks out of balance by being perfectly symmetrical. Federation architecture is not symmetrical like the Victorian era predecessors, rather it is an asymmetric compositional balance that in your case should be recognised and countered appropriately with the design of the extension. When selecting appropriate extended cladding material it should be working towards texturally balancing the building and being complimentary overall. Professional recommendation you revisit the articulation of the upper extension, at the very least loosening up the fenestration with more glazing and potentially a more complex roof form with a smaller projecting gable (offset) as a reference to the frontage. The cladding choice becomes less critical, and shingle texture that ties in the roofing texture could work well. Weatherboard is bringing something new in, and if you go flush panel without a more contemporary design and articulation it will look wrong Good luck PD :) www.pauldistefanodesign.com