How much is my house extension, home renovation going to cost me?
This is the question most frequently asked by our clients. At the start of a potential house renovation project it is impossible to quote builder’s quotes without working drawings and a list of materials, fittings and fixtures.
Building costs for house extensions or home renovations can vary considerably depending on a number of criteria:
- Choice of building materials, fittings and fixtures – bathroom and kitchen tap fittings, tiles, window frames, heating & cooling, lighting.
- The extent of client involvement – does the client choose to perform any of the building works such as painting
- Commencement and duration of the building works – does the project extend over the Christmas holiday break or during seasonal busy periods – this will add to any interest cost and/or rental costs if you need to move out
- Seasonal building market conditions – the number of rain affected days – this will add to any interest cost and/or rental costs if you need to move out.
- Town planning delays – this can result in additional costs and potentially add months to your building project or house renovation.
- Size and competence of the selected building firm or builder – the bigger the business the more overheads and, by necessity, will pass this cost on to you and increase the builder’s quotes.
- Each builder will factor in a different profit margin for a professional builder’s quote.
- Varying professional fees – architect, draftsperson, town planner, structural engineer, soil report, building surveyor, etc.
- Abnormal ground conditions requiring additional site costs – a sloping block and/or the need to dig deeper to reach solid ground and so concrete pours will vary.
An estimate from a quality builder can prove extremely useful at this early stage as a guide to what you can spend on your new house, house renovation or extension. An estimate of home extension costs can be provided based on floor area rates and building costs from previous projects. It is not possible to provide an elemental estimate (as provided by a Quantity Surveyor) at this stage due to the preliminary nature of the documentation available to work with.
If a builder’s quote gets submitted without listing the scope of work, then you will need to examine each quote vigilantly to ensure nothing has been left out, and be wary of unrealistically low prices as you may be the victim of a budget blow out further into your building project. Base prices for building projects can blow out with understated ‘Optional Extras’ once you have signed up.
Estimating House Extension Costs
Some real-world costings on the price of extensions and additions to your home.
If you decide to use a Design & Construct Builder, in addition to your plans they provide permits, soil report, engineering as well as construction in their pricing. While their designs are not necessarily architecturally creative, their prices generally end up being the lowest. You may choose to use an architect or designer/draftsperson to draw up plans for builders to quote on. If you want something creative or different from the majority of extensions in your street, this option may be for you. However the final cost is likely to be greater than a Design & Construct Builder. You may also end up with a wonderful set of plans that cannot be realised without exceeding your budget. Some builders are prepared to comment on your house plans as they’re being drawn. They are in a good position to make suggestions regarding design and materials to keep your costs down or at least to give you costs before your plans are finished. When you are seeking quotes on your plans, they may be able to submit a very tight price due to their familiarity with them.
As a rough guide, the following fees may be charged. Based on a home extension contract costing $150k requiring a planning permit, you will typically be looking at:
- Architect: $9,000 – $15,000
- Draftsperson: $3,200 – $6,500
- Land Surveyor: $800 – $1,850 – if required
- Geotechnical engineer (soil reports): $300 – $550
- Private Town Planner: $1,000 – $10,000
- Structural Engineer: $750 – $1,400
- Building Surveyor: $1,500 – $2,250
Your costs will also be influenced by the following factors:
Choice of materials, fittings & fixtures;
- seasonal fluctuations;
- delays – town planning, weather;
- builder’s profit margin
- how much you can do yourself – eg painting
- soft landscaping
- abnormal ground conditions requiring extra concrete poured or site costs
For more information on how to save, read about our drafting services in Melbourne.