Residential Engineering

Waffle Raft Slab vs Conventional Stiffened Raft Slab

Waffle Raft Slab vs Conventional Stiffened Raft Slab

Advantages of a waffle raft slab in comparison to a conventional stiffened raft slab

What are waffle raft slabs, and how are they constructed?

Waffle rafts are a particular form of raft slab where the raft, including ribs, is constructed on a prepared flat ground surface. The regular grid of ribs is formed using void formers.

The construction is completely on-ground rather than in-ground like a conventional raft slab and this has several features:

Adequacy of Drainage

Waffle raft slabs are commonly utilised in the NSW residential market because construction is more controlled and less impacted by wet weather.

Regardless, the benefit of a waffle raft slab is that it has a flat building platform preparation level so rainwater runoff can be drained, providing that there is adequate temporary and permanent site drainage.

Alternatively, conventional raft slab tends to be more affected if an extended period of wet weather were to be experienced following the excavation of all the beam trenches. The trench walls and bases could become soft and will require to be re-excavated and dewatered, which would be troublesome and time-consuming.

Our Experience

Here at Residential Engineering, we have a team of professionals with over 30 years of experience in this industry. We have designed over 250,000 waffle raft slabs in NSW following the AS2870 compliances. Contact us today for more information.

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