Waterproof Concrete Roof Decks…

...and other at-risk exposed concrete

Waterproof Concrete Roof Decks…


Given the large number of situations where concrete is exposed to the elements, waterproofing is a very significant topic with broad application.
Markham – adding life to concrete.
We’d particularly like to focus on exposed roof slabs as a prime example, although the technologies discussed do have application to many other situations – more information on this later.



Waterproof the Concrete Itself

The typical design response is a membrane. There are a number of disadvantages with this approach, particularly the cost. Membranes also can divert moisture via capillary action, conveying it around the very areas they are intended to protect.
Markham – adding life to concrete.
The best approach is to waterproof the concrete itself, by using Aquron penetrating hydrogel treatment. This treatment is ideally applied in two forms to the slab, as an admixture, and spray-applied to the exposed face. This provided belt-and-braces reassurance of waterproofing the concrete integrally, immobilising internal moisture and preventing its ingress.
Markham – adding life to concrete.
Aquron hydrogel treatment remains active for the life of the concrete sealing and self-healing static microcracks up to 0.5mm.
Concrete construction
Markham – adding life to concrete.

Waterproof the Spaces Between

Obviously it’s not enough to waterproof the concrete alone – water must be kept from the spaces between the slabs. For sealing penetrations and expansion joints, we recommend Superswell waterstop. This delayed-action gasket is the ideal solution for permanent gap sealing.
Markham – adding life to concrete.
Waterproofing the spaces may also include the use of slab joint drains, depending on the size of the structure and the overall span of the exposed slabs.
Markham – adding life to concrete.

Planning to Avoid Cracking

You also need to be sure that water will not enter through unplanned cracks. It’s important to plan slab sizes and saw cuts to remove the risk of structural and movement cracking later in the life of the structure. It’s essential to understand the importance of this planning phase in the context of the waterproofing and the long-term life of the structure.
Car park concrete roof deck needs Aquron hydrogel
Markham – adding life to concrete.


The holistic Markham approach to waterproofing can completely remove the need for waterproofing membranes in many structures.

  • Intelligent slab pour and expansion joint design, to avoid movement cracking.
  • Aquron hydrogel treatment as an admixture and spray-applied to the exposed face.
  • Superswell waterstops, and strip drains if required, for water control at the joints and penetrations.

It’s crucial that this approach is implemented from early design stages.
Markham – adding life to concrete.

Other Applications for Waterproofing Exposed Concrete

‘Exposed’ is a broad term.
Markham – adding life to concrete.
The risk elements may be beneath ground, with soil moisture penetrating into a basement. Exactly the same principles can be applied to basement waterproofing as to rooftop slabs. This includes shotcrete walls.
Markham – adding life to concrete.
Marine structures are a more extreme example, but again will benefit from Markham’s multi-pronged approach.
Markham – adding life to concrete.
If you’re involved in design of structures at risk, get in touch! We can show you past projects, and review your current design with you. We have an experienced and energetic team, and we’re looking forward to helping!

Download the overview of the Aquron Waterproofing System

Markham – adding life to concrete.
This article previously published as “Waterproofing Exposed Concrete”.


Lets talk
about it

We understand that choosing the correct solution and type of product is essential for the success of any project. MARKHAM GLOBAL has a technical support team with many years of concrete industry experience and successful project applications and are ready to help you find the right solution for your application.

Ask us a question

0333 456 5758

Monday to Friday.

9am to 5pm.