What are the biggest reno no-nos that will lose you thousands? Read on to find out.

1. Overcapitalizing

Average loss: $40,000

Undertaking a renovation which gives you the best house in the street, is not always guaranteed to get you the best price. For example, if you are an owner occupier in an area where there are a lot of rental properties that have been neglected and not well-looked after, it doesn’t matter how much you spend to your house in terms of improvement, the rest of the neighbourhood is going to let the value down until such time as these properties are improved as well.

That's because the streetscape and the neighbours’ houses influence re-sale value. Sensible renovations should take these factors into consideration.

2. Ugly renovations

Average loss: $28,000

Renovations should be sympathetic to the original building. Starting an extension without considering the form or visual impact of the exterior materials being used so that the renovation appears as an add-on rather than part of the house, can potentially devalue your property by at least $28,000 on average.

For example, if you stick a flat roof weatherboard box on the side of an older home with a pitch tile roof, it’s going to look pretty ordinary and it’s going to look like the cheapest possible way that you can add a room. That’s not necessarily going to appeal to too many people when you come to sell the property.

3. Over-indulging

Average loss: $25,000

Choosing expensive fittings and fixtures such as imported cook tops, taps, door handles and tiles don’t necessarily translate to higher selling price.

What impress buyers is light and space as well as good construction and zero faults. That’s what they’ll happily pay for. Some renovators believe expensive fixtures represent good design, but purchasers often don’t like the previous owner’s choice.

Middle-priced Australian-made products are often more serviceable and will bring the same price when you sell. Some renovators spend $15,000 to $20,000 more than they should, therefore, they’re not giving themselves the chance of getting those expenses back.

4.  No playground, no barbeque

Average loss: $18,000

Poorly considered site planning, including extensions that can leave unusable outdoor spaces or are overwhelmed by fences and retaining walls close to important rooms will devalue the whole property.

If you look at the new home designs that are current at the moment, you’ll see that there’s a really big emphasis on lifestyle or an outdoor living. Whether you’re buying a new home or an old home, people are looking for these features these days. It doesn’t mean spending a fortune, it just mean organising the space properly so that you got a good open family area and an outdoor living area. Views to the back garden are important to a lot of people especially with young children, as they want to be able to supervise them when they’re outside.

5. Suburban desert

Average loss: $20,000

Contrary to many people’s belief, removing trees can sometimes cause more damage to a home than does leaving them. A large attractive tree can add $10,000 - $15,000 to the value of a property in some areas.

Provided trees are not damaging to the building, they can add really value in terms of sun shading and in terms of outlook and they can be very appealing to a lot of people, unless they are the sort that drop a lot of rubbish on the roof and you have to clean up the gutters. That could be a bit of a nuisance to people. The thing to be weary of is that if there’s any cracking evident on the property, if it’s bad, then a tree needs to be removed. Ideally, leave the tree where it is and deal with the cracking in other ways.

6. Illegal building

Average loss: $30,000

Undertake construction work without a permit. In some suburbs, one quarter of all houses had an illegal extension. A prospective buyer having a pre-purchase inspection when you try to sell usually picks this up. Illegal building ultimately costs some owners $30,000 or more to make it comply with regulations.

7. Faulty structure

Average loss: $25,000

Installing new kitchens and bathrooms without first checking that the sub-floor structures are sound. Many new kitchens are virtually destroyed in the first four years by floor subsidence.

8. Do It Yourself

Average loss: $18,000

Homeowner-installed wiring and plumbing. This is illegal and dangerous and may be picked up by an pre-purchase inspection.

9. Expensive rip offs

Average loss: $8,000

Undertake expensive underpinning to remedy brick cracking without ensuring that this is the best option. In many cases low cost watering systems and tree pruning do the job and underpinning will cause more cracks in other parts of the house. Some owners have spent $20,000 unnecessarily.

10. Jerry-built

Average loss: $12,000

Join the renovation onto the existing building in an unsatisfactory way. This can result in major cracks appearing between the existing and new building because of incompatible structural systems.

The most important thing people can do at the start is to get their design concept right and the smart renovators get professional help at this earlier stage as once the building starts it is expensive to change