The Holistic Solution – A Complete Waterproofing System for 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.
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.
The best approach is to waterproof the concrete itself, by using 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.
Hydrogel treatment remains active for the life of the concrete sealing and self-healing static microcracks up to 0.5mm.
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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 a delayed-action gasket as the ideal solution for permanent gap sealing.
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.
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.
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Structural Concrete Waterproofing, Completed
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.
- Advanced nanoparticle hydrogel treatments as admixture and spray-applied to the exposed face
- Delayed-swell waterstops, and strip drains if required, for water control at the joints and penetrations.
It’s crucial that this approach is implemented from the early design stages.
And this approach has a name: it’s called TOP-TECT®.
Other Applications for Waterproofing Exposed Concrete
‘Exposed’ is a broad term.
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.
Marine structures are a more extreme example but again will benefit from Markham’s multi-pronged approach.
If you’re involved in the 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 TOP-TECT® overview brochure for free.
For more discussion on this system, an on-demand webinar is available.
