How Much Does a Second Storey Addition Cost? [2024]

When you extend your home, you have two choices -- out or up. Some homeowners shy away from building up, thinking the second storey addition cost will be prohibitive compared to a ground floor home extension.

But is this really the case, and how much does a second storey addition cost? Read this guide to find out about:

• How much does a second storey addition cost?
• Second storey addition vs ground floor extension: which is more cost effective?
• What are the benefits of a second storey addition?
• Choosing a builder for your second storey addition

How much does a second storey addition cost?

A second storey addition may cost less than a ground floor addition, but it's still a major expense. Estimates vary, but renovators who have been through the process estimate the cost of a second storey addition to be from:

• $1,850 to $3,300 per square metre (m2)
• That's quite a spread, but a number of factors influence the cost of a second storey addition. These include:
• The size of the project
• The quality and price of construction materials and inclusions
• Whether the ground floor needs reinforcing to carry the load of the extension
• Council fees and engineer's reports will also add to the cost

Read more: Getting approvals checklist

Second storey addition vs ground floor extension: which is more cost effective?

In most cases, second storey additions cost less than ground floor additions. When you extend your home outwards, the cost of the foundation alone can make it more expensive than adding a second storey.

However, you should be prepared for much more disruption in your home if you add on a second storey, and this may also involve unexpected costs.

While builders can leave you undisturbed while they work outside on a ground floor addition, they will need access to your home throughout the construction process if you're building up.

Since your roof will need replacing, you may even have to find temporary accommodation until your upstairs addition is at the waterproof stage of completion.

What are the benefits of a second storey addition?

Besides being cost effective, there are many good reasons to consider adding a second storey to your home. Here are just a few:

• Expand your living space – like other home extensions, you'll gain more space that can be used for extra bedrooms, bathrooms, storage or other needs.
• Don't lose your outdoor space – unlike a ground floor extension, a second storey addition doesn't mean sacrificing some of your garden.
• Improve privacy and views – upstairs rooms offer more privacy from family members and neighbours' windows, while also offering views beyond your boundary.
• Add value to your home – a second storey is a big investment, but one that will add considerable value to your home if you decide to sell.

Choosing a builder for your second storey addition

To make sure your home renovation goes smoothly and avoid expensive problems, make sure you choose a home extension builder who specialises in or has extensive experience in building second storey additions.

Don't take their word for it. Instead, visually inspect some of their previous work and speak directly with one or more of their previous clients. You need to be absolutely sure they will work fast and efficiently, disrupt your daily life as little as possible and respect your privacy while they work.

A good builder with extensive experience can get a second storey addition to a waterproof stage of completion in two to three weeks. After that time, there's still plenty of work to be done, but you will be able to go back to your normal life, except for minor disruptions such as temporary loss of water and electricity while the tradies do their work.

When they're finished, good builders will leave a site clean, tidy and ready to occupy. To make sure you choose the best builders for your second storey addition, compare quotes from several local professionals.

*Costs and prices in this article are indicative and should only be used as a guide. They also vary locally and are subject to market forces.