How much does a Second Storey Addition cost?

We are often asked – ‘How much does a Second Storey Addition Cost?’ And ‘Should I extend out or build up? Which will cost more?

Adding a Second Storey does not always cost more than a Home Extension. Sometimes it actually makes more sense to add a second storey, but homeowners can be put off by thinking that this costs more than a ground floor home extension. This is not necessarily the case.

Second Storey additions are a great way to add space and additional rooms to your home, without losing much space from your existing floor-plan, and without losing yard space.

Ground Floor Home Extension or Add a Second Storey?

A Ground Floor Home Extension is probably a more suitable option if you want to add Open Plan Living such as a new Kitchen, Living and Dining area and modernising your dated home.

If you need to add children’s bedrooms with a bathroom, and/or a master bedroom with ensuite with an additional living area or parent’s retreat, then a Second Storey addition may be a better option.

Ground Floor Home Extension costs

Costs for a ground floor home extension can generally be estimated using an amount per square metre. This amount however can be quite variable. It can depend on the type and quality of finishes selected. It can also vary considerably based on the number of wet areas such as bathrooms which will increase the amount per square metre.

A Home Extension will also need new concrete foundations and a slab to be poured. These are costs that are generally avoided or minimised in a Second Storey Addition.

As a rough guide, we estimate that adding Open Plan Living to the rear of your home will cost $160k+. A Home Extension for this price would typically include a new Kitchen, Dining and Living Areas.

Second Storey Addition Costs and Design factors

A 2nd Storey Addition will involve costs on the ground floor to modify the floor-plan to include a location for the stairs. This is one of the first things that you will need to decide and is very important to the overall design. An experienced Home Extensions Designer can you walk you thru the options here.

What rooms will you have upstairs? Second Storey addition design ideas.

Deciding on what rooms you require upstairs will have the most impact on your 2nd Storey Addition costs e.g. will there be a master bedroom and ensuite, children’s bedrooms and bathroom, separate WC, activity area? This is something that you would talk thru with both your Designer and Builder in the early stages.

Save costs with no slab and Lightweight construction

Unlike a Ground Floor Home Extension, a 2nd storey addition does not normally require any foundations or concrete slab to be poured. This is a big saving in the construction of the 2nd storey. The 2nd floor addition is usually a light weight construction (timber frame) on top of the existing home.

The extra weight of a double brick and suspended concrete slab to a 2nd storey would add considerable load to the existing home’s walls and footings. The additional cost to strengthen the ground floor structure to carry this extra weight would not make a 2nd story cost effective for most.

Coloured Render Saves Cost on Painting

You will need to select cladding for the external walls of your 2nd storey addition. An example is James hardies blue board cladding, a proven cladding product that is finished with an acrylic render. This product has the colour in the render and means that you can have any colour and save on the costs of painting the second storey.

Aluminium Windows on your Second Storey addition

You will require new windows to the upstairs addition. We recommend aluminium windows as the cost of Painting external windows on a second floor can be expensive if scaffolding is required. Again another way of saving costs on your Second Storey.

Ceiling Heights upstairs

The floor to ceiling height will have a major impact on the cost of your 2nd Storey. Councils have a maximum allowable overall ridge height which is taken from natural ground level. As such your 2nd storey ceiling heights may need to be reduced. In terms of cost, the higher the ceiling the higher the cost. However, there are ways of achieving a perceived higher ceiling height by using coffer or raked ceilings. Again, an experienced Builder will be able to talk you thru the options here.

So How Much Does a Second Storey Addition Cost?

With 30 years of experience in building 2nd storey additions, we estimate that the cost of second storey addition starts at around $220k. A typical example for this price would be a Second Storey that includes a Master Bedroom with an Ensuite, Walk-in Robes and an upstairs Living Area.