Greville Pabst, CEO of property valuers WBP Property, said that many homeowners are surprised to learn that the money they have spent on their homes has not resulted in an equivalent increase in the price it is likely to sell for.

“Cost doesn’t always equal value,” Mr Pabst said. “When you commence a renovation, be conscious of how much you’re going to spend and in what areas.”

Hodges Real Estate’s Angus Graham added that homeowners can run into trouble if their renovations costs surpass the value that has been added to the property.

“As a rule of thumb, properties in the entry level end of the market are less likely to return costs associated with anything above basic improvements,” Mr Graham said. “Properties in more prestigious markets offer better returns on external renovations and therefore can be invested more heavily in.”

And while it is rare for renovations work to detract from the value of a home, jobs that tend to have a negative impact on property values include:

1. Poor landscaping: “If outdoor renovations don’t match the character and design of the house, they can be a waste of money,” Mr Pabst said, explaining that a hedge garden will complement a Victorian house, but a tropical garden may not.

He added that cutting down certain trees can be costly. “Don’t underestimate the value of natural aesthetics, such as a nice flowering magnolia tree or nature feature. Aesthetically items like these are pleasing so be careful of cutting any items like this down.”

2. Additions don’t match original building: Added rooms that use vastly different exterior materials from the original house can, in certain instances, paint a picture of a disjointed house that puts many buyers off and can devalue a home by as much as $30,000.

This is especially true when the structure of a renovation is not compatible with the existing building, causing cracks between the buildings.

3. Creating dark rooms: Any work that dramatically blocks natural light flow will devalue a home. “Orientation is crucial,” Mr Pabst said. “Be aware of how much natural light flows into the property. Renovations should try to maximise natural light, particularly in the living areas, where most of time is spent in the house.”

4. Custom builds: Renovating too much to your own tastes or likes can drag down a home’s appeal to the wider buying market and subsequently its value. “Make sure any renovation you do appeals to the wider market,” Mr Pabst said.

5. Appealing to the wrong crowd: Similarly, home improvements need to match the tastes of the kind of people that usually purchase homes in the area. If the home is in a lower- or middle-income area, installing expensive fittings and fixtures such as imported door handles won’t increase the value.

6. Illegal building: Prospective buyers tend to stay well clear of homes with illegally built extensions — and for good reason. It can cost up to $40,000 to make illegal building work comply with regulations and it’s something owners cannot hide because would-be buyers pick up on the illegal work during pre-purchase inspections.