A question often asked. In reality, well designed and well-placed concrete should be waterproof. However, waterproof concrete is often requested by insurers as one of the forms of waterproofing. But it’s not always 100% effective.

Waterproof concrete is significantly more expensive than its ‘non-waterproof’ counterpart, but like any concrete, and if badly placed, it can still crack. Whether concrete is waterproofed or not, a crack is still capable of letting in ground, perched, or surface water.

The commonest issue with all types of concrete is bad placement at site with bad compaction, honeycombing and poor joint detailing being a source of water ingress after placement. Other factors such as weather and temperature during placement and curing can also play a part in causing faults.

With construction budgets under pressure like never before, careful consideration needs to be given to whether its best to use waterproof concrete below ground or perhaps the consideration of other Type A solutions using a barrier method to seal either external and/or the internal faces of the concrete.

Depending on the type of structure and its location and environment, it may be that some or all waterproof concrete could or can be omitted, potentially saving construction costs. Ground conditions vary hugely across the UK with different soil types and ground make up. Some soils drain well, some do not. If there is also a rock stratum to consider, chalk or granite with a high degree of perched water, these all can have a bearing on whether a waterproof concrete should be employed.

Ultimately a structural engineer will decide on the concrete specification and design, but by working early with a structural waterproofing expert possible savings can be made at the planning and pre-construction stage.

On a final note, many admixes that are added to concrete to make it waterproof do have the ability to self-seal when water finds a fissure or crack, but there are limits. Anything over a 0.2mm crack width is putting a potentially unrealistic demand on its watertightness. And again, if the concrete is not well placed, problems can still occur.

Structural Waterproofing Services offer a full structural waterproofing design and expert installation service from simple residential basement conversions through to multi deck basements in commercial, infrastructure and industrial settings. Whatever the structure, if its concrete and below ground, you should look to find the right expertise and advice when it comes to sealing against water ingress.

Structural Waterproofing Services can work on your behalf with all the UKs leading structural and new build insurers.

Get in touch with regards your next project and we can demonstrate how best to handle the risk of leaks in any concrete structure. Structural Waterproofing Services are always happy to offer initial advice at the outset of a new scheme or project.