Common Problems with Slabs for New Homes

We do lots of slab inspections for new homes. In fact, it is the one of the most common types of inspections we do. This is due to it being very important to get the concrete slab right – because if you don’t you will most likely have structural issues with your new home.

Here are some of the common problems we find when we do a concrete slab inspection:

Concrete slab is not level

It is surprising how often we find the poured concrete slab is not level. Uneven concrete will not fix itself and if left unchecked will cause more and more damage to your home as time passes.

Vapour barrier not installed correctly

A concrete vapour barrier is used to prevent moisture from getting into a concrete slab. When it is installed it needs to extend past the concrete and be lapped and sealed before the concrete is poured. If it is not installed correctly then the concrete floor will be in continuous contact with moisture. This can lead to many problems, including problems in laying flooring materials on top of the concrete.

We always make sure that the vapour barrier is installed in accordance with the relevant Australian Standard AS 2870 Slab & Footing Construction.


This common problem is called honeycombing because the concrete resembles the honeycomb nests created by bees. It is caused by different things going wrong during the concrete pour – including improper cement to water ratio and lack of integrity in the perimeter form work.

Whatever the cause of the honeycombing, it can cause serious damage to your home as moisture penetration can occur. This can result in concrete cancer, which is the rusting of the steel used to reinforce the concrete.

Find out more about honeycombing in concrete slabs.

Concrete slab does not match the floor plan

Unfortunately, we have found instances where the concrete slab does not match the floor plan or the engineer’s drawings. The earlier this issue is picked up the better.

Cracked Concrete

The main causes of a concrete slab cracking include too much water added to the concrete mix, concrete drying too quickly and lack of control joints. There are four main types of cracks in concrete. These are hairline, shrinkage, settlement and structural. Although all concrete cracks need to be investigated, settlement and  structural cracks are the most concerning. Settlement cracks can cause part of the slab to sink, whilst structural cracks may require the entire slab to be redone.

new home inspection honeycombing

If you have a question in relation to problems with concrete slabs do not hesitate to contact us

Our slab inspections will  provide you with peace of mind and potentially save you a lot of money.

Phone 1800 466 424, send us a message via our contact page or send an email

New Home Building Inspections are an independent inspection company specialising in inspections for new and existing homes. For new homes we specialise in all stages of construction. This includes pre handover inspections, house frame inspections, lock up inspections, pre paint inspections and slab inspections.  For existing home we do pre purchase inspections, pest inspections and combined building and pest inspections. We also do vendor reports and maintenance reports