Hi Eric, Great question, that applies to so many people in similar situations ! Typical house alterations & additions scenario with limited budget... What I recommend to my clients in those cases is usually a fixed price lump sum contract to start off with. The way that works best is that we prepare a really good and detailed set of drawings for them, and we try and foresee as many of the potential issues as we can, then we get prices from builders and lock a price in for that scope of work. That's part 1, which gives you a good level of price security. In addition, you then need a considerable contingency sum for the unknowns. Whenever one of those comes up, the builder will price them as 'variations' to the original contract, and we would check and approve (or don't approve them) for our clients. So this is the second part, which pretty much works like a cost-plus. That way you get the best of both worlds. A pure cost-plus I would only ever recommend with a builder that you know and trust really well, and if you are under time pressure. Otherwise most clients would be generally much better off following our usual recommendations as described above... Good luck with it all ! Best Marc

Go with option 1. Use standard construction processes - skillion metal sheet roof over foil backed blanket. LVL rafters and timber frame walls which the carpenter will make on site. Probably go with a slab on ground and be aware of termite controls between new and existing. Excavate rear yard and build retaining walls with drainage behind them, probably also need a couple pits for surface water. Retaining walls constructed and engineered properly are expensive so be prepared. Treated pine sleepers are nowhere near a suitable solution once you're above 600mm. A builder or a carpenter would go through $20k in materials and some labour for plumbers, excavations, electrical, etc. Plans, documentation and council approvals will soak up $10k or thereabouts. Yes its a simple little job but it comes to economy of scale and some areas will cost the same or take the same amount of time as a larger project.

I am sorry you feel anything said to you was "rude". I am sorry I couldn't find a way a way to explain how serious the matter is in a way that you like. This conversation was for your benefit, to help you and your neighbour avoid bigger problems later. Please try to understand that. So you say you are in Canberra? Canberra has heavy clay soil. Your structural engineer friend cannot say the wall is good without talking about the drainage. Drainage is an important part of the structure. Correct drainage is even more important where there is heavy clay soil. Canberra does not have 'council approvals'. So I am not sure what it is you think you have when you said it is "council approved". Please respect that I am saying this because it is important. I am not trying to be negative and rude. It is important for you and for your neighbour that the wall is built correctly. The pictures look wrong. That is why people talked about it, instead of simply answering your question about how to make it "not look ugly". No proper drainage is visible behind the wall as shown in the diagrams provided in a previous reply. The idea of drilling drainage holes afterwards is wrong as explained in a previous reply. No-one is trying to be negative and rude. Everyone is trying to help you complete your build safely and correctly so that you and your neighbour do not have bigger problems later. I hope it works out alright for you and for your neighbour.

Could be a range of thinks. First look for air leaks using a candle, carefully. Around windows as well, seal all gaps. Lack of wall insulation and underfloor insulation next culprits. Good underlay will help some air leaks, you can also add some gap sealers to floor first to resolve air leaks. Your duct work and vents need checking. Heavy curtains to floor can help with windows as can double glazing a little. If you grab one of those infrared thermometer they have been using to check forehead temps you can see which walls are colder. Hanging curtains can help