The Pros & Cons Of Building A Sunshine Coast Granny Flat On Slab VS Suspended Floor Part 2


In this part 2 series of the pros & cons of building a Sunshine Coast granny flat on slab vs suspended floor, we will explore the cost, timeframe and process differences. One of the main benefits of building a granny flat on a slab is that it is often cheaper than building on a suspended floor. However, there are also some drawbacks to this approach. Building on a slab isn’t always possible on all sites – an important factor to consider if your land is sloping.

Thinking of building a Sunshine Coast granny flat? Enquire with the building experts.

Cost comparison

When building a granny flat on the Sunshine Coast, cost should be a major consideration. While a slab-based granny flat is more cost-efficient, a suspended floor may require more investment.

The cost of building a granny flat on a slab depends mainly on the size and type of construction materials used.

A granny flat built on a suspended floor, meanwhile, is more expensive due to the complexities involved in the design and construction. The cost to build a suspended floor granny flat includes the cost of materials, plus additional costs for the design and engineering of the foundation. Moreover, on certain sites this may be the only possible option when considering building on the side of a mountain, for example.

Ultimately, a person's budget for building a granny flat and the land type on the Sunshine Coast will determine the best option for them.

Time frames

When it comes to building granny flats on the Sunshine Coast, the time frame for building depends on the type of construction chosen.

Slab-based granny flats tend to be faster to build since they involve a simpler construction process. On average, it takes 1-3 weeks to complete the construction of a slab-based.

Suspended floor installations, meanwhile, can take anywhere from 4-6 weeks. This is due to the added complexities involved in the engineering and preparation required for the construction of the foundation.

Granny flats being built for investment purposes should factor in the time required for construction. An investor may opt for a slab-based granny flat if their time frame for completion is short - of course should your site permit this style of construction.

Step 1 - Consultation & Price Estimate

The process

The process for building a granny flat on either slab or suspended floor starts with the approval required from the local council. Once these approvals have been secured, construction can begin.

Slab-based granny flats involve the pouring of a concrete base to act as the foundation. This is followed by the construction of the walls and roof, installation of doors, windows, and other fittings. Plumbing and electrical wiring are then done before the flooring is laid.

In a suspended floor granny flat, lifted foundations are first constructed. These are followed by a bottom plate made of lumber and concrete footers. The walls and roof are then constructed, with electricity and plumbing carried out before the partitions and fittings are put in. Finally, the flooring is installed.

Building a granny flat on slab or suspended floor allows for more space compared to other options. When building a granny flat on slab, a concrete base is poured, followed by constructing the walls, roof, and other fittings. Electricity and plumbing are done before the flooring is laid.

For a suspended floor granny flat, raised foundations are constructed and a bottom plate and concrete footers are added. Then, the walls, roof, and fittings are put in and electricity and plumbing are established. Lastly, the flooring is installed.

The total cost of building a granny flat on slab or suspended floor will depend on the type of building materials used, the complexity of the granny flat, labour charges, and other factors. 

Palm Springs Aesthetic

Contact The Shed House team today to discuss all of the options available to you & your preferred build site.

Contact us for more information regarding building a Sunshine Coast granny flat. Trust your local Sunshine Coast builder.