Depending on what you would like to do with a renovation the costs can vary significantly. If you're considering making significant structural changes it might be cheaper to start from scratch by knocking down and rebuilding. Generally, building a new starts from $200,000.

For a knockdown and rebuild you would generally allow around eight to 12 months. If the building is subject to planning approval, this can extend the time considerably.

Unless your property is free and clear from all liens or encumbrances, your mortgage is secured to the structure as well as the land. Your lender has an interest in the building itself, so you cannot unilaterally destroy the lender's security without permission.

No, stamp duty fees do not apply when knocking down and rebuilding a home on an existing site.

The Engineers doing the test will classify the lot as a “P” site being “Problematic”. Do not be alarmed. This just tells everyone that reads the soil report that the something has happened to the lot requiring additional engineering attention. This “P” is due to the soil being “fluffed” up during the excavation of pipes, stumps and will lose its bearing capacity for the next house to be built on. This will result in slightly higher footings and engineering costs as these will have to go through the “fluffed” up soil into the natural soil below usually at least 600mm. The cost of this is more expensive than an empty block but is not significant enough to prohibit the building of the new home. Cost vary depending on the block and house design too.

Additional costs that also will be encountered is the Demolition Approval from a Building Certifier or Local Council which is around $1,000. The disconnection and capping of the water and sewer pipes by a licenced plumber will cost between $600 and $800 and is generally done the day before or the morning of the demolition. The above two items may or may not be included by the demolition company in their quote. The other item that needs to occur is the disconnection of the electricity. The energy authority generally will only speak with the homeowner directly and not your builder or demolition company. This conversation should take place early in the process to ascertain how much time they require to organise and do the work. Generally, 4 to 6 weeks before demolition is required, but this does vary and will need to be co-ordinated by the homeowner to have it done prior to the demolition day. This will also dictate, to an extent, the move out date of the homeowner and may, depending on the authority, take place weeks before the demolition company can be on site.

Demolitions normally only take up to three days but can take up to five depending on the weather.

People often think the Demolition Companies will pay them for their home or salvaged materials. In some instances, this may be the case but in the vast majority of cases it does not apply. If you can get them to take it away and do the associated site works at no cost, then that is a cost saving by not having to pay the above outlined costs, however this is not a regular occurrence. Demolition and recycling yards are currently over supplied, only a house with redeeming features is worth their time and money to salvage.

Most demolition agreements, when you accept the quote, the house structure and attachments become the property of the demolition company and items cannot be removed by the homeowner unless previously discussed and approved by the demolition company. Always read the demolition quotes carefully.

GW Homes can assist you in including the demolition costs as part of the new build contract and co-ordinate this for you if you wish. If you are borrowing, check with your lender first to ensure they will be happy to have the demolition costs included in the loan or whether you will need to fund the demolition costs yourself.