Walls are defined by council as 'Structural ' regardless of whether it is a non-loadbearing or structural wall. Simply putting a wall up will give rise to issues including natural light, ventilation and depending upon the class of building: safety, egress, fire issues etc.

A substandard/non-approved room will not add value at the time of sale any building inspector will pick up a non-approved room, raise the issue with a purchaser and give them a bargaining point to reduce the sale price or walk away from the deal.

Less when you pay  back the 300k you borrowed but it is still 500k compared to 200k.

Special by-law granting you exclusive access to the path. Discuss with your lawyer & surveyor prior to signing the building contract. (Have your solicitor review your construction contract if it isn't a standard form approved by either the Master Builders Assoc or RAIA.

Contact your office of fair trading to find out what you can (if they will talk to you as a prospective owner).

Otherwise, find out what the claim is worth, your unit's liability if you lose and negotiate a price reduction. If neither appeals, steer clear until it is resolved.

Which state is the property in Bob?

Selling may expose you to capital gains tax, buying one or 2 others will  mean paying stamp duty. Consider refinancing to buy one or 2 other cheapies which are cf+ which will assist in your overall portfolio balance.

You may need to speak to a few consultants: town planner, architect, structural engineer, civil engineer, traffic engineer, surveyor etc  all before you get to speaking to a builder.

The book is called the Australian Standard Method of Measurement published by the AIQS, alternatives would be available from the Property Council of Australia.

The appropriate book would depend upon the reason that you need to measure the floor space? Examples would be NLA, GLA and FSR.

Look to having a 100%  mortgage offset account linked to the loan, that way your 'surplus' cash is offset against the capital that you have borrowed (and lowers the interest payable as well as being accessible without having to be redrawn etc).

You will need access to a great crystal ball to determine what will happen to interest rates over the 3-5 year timeframe, an even better one for 5-7 years or more.

Kenneth, the amount claimable will be calculated as the assessed value of the land less the threshold (about $376k – refer to the OSR website Land Tax Calculator). Simply use the calculator with the value of the subject land eg: $2,500,000 which will give you a land tax liability (on a single holding basis) = $34,888

If you are the seller, you would need to get the buyer's agreement esp if they were buying with vacant possession.

If you are the buyer, you don't own the property yet so you cannot enforce any of your wishes over the vendor. The vendor may agree that you can lease out the property however it would be very conditional – vendor keeps rent up to settlement, buyer pays cost of finding the tenant, buyer accepts any damage which the tenant causes prior to settlement, buyer insures the premises etc.