Preservation and protection

Faced with a number of location challenges, a new museum in Marseille has benefitted from highly innovative waterproofing membrane technology

With a greater number of buildings now constructed close to bodies of water such as the sea, lakes and rivers, developers must carefully consider the exposure conditions and how these will adversely influence the use, watertightness and durability of the entire structure. As the high water table, aggressive soil conditions and the corrosive effects of seawater will pose unique risks to the building, a proven and reliable waterproofing membrane has fast become one of the most important specifications at every construction project.

A high performance waterproofing membrane improves the concrete’s structural performance and durability by providing constant protection from sulphate, chloride and water ingress. The selection of the right material solutions early on in the design stage of any project is important, as it is difficult and costly to do something about concrete cracks and water leakages later. By getting the specification right first time, you can prevent water ingress – and the many causes of concrete corrosion – with one relatively simple application.

High water tables cause hydrostatic pressure to be exerted beneath basement floors and against the substructure walls. This forces water into the building through cracks, joints and any porous substrates and can contribute to mould, corrosion and other moisture related problems – which in turn can lead to major structural damage. So it’s vitally important to choose a waterproofing system that is resistant to chemical attack, mechanical damage and hydrostatic pressure.

The most suitable solution is to utilise an impermeable barrier that not only restricts moisture or water movement into the building, but stops water migration between the waterproofing membrane and the building itself. Utilising over 50 years of experience as innovators in the waterproofing industry, Grace Construction Products developed the market-leading Preprufe® system to combat the harmful effects of water migration and prevent concrete deterioration before it starts.

Causes for concern
Whether directly or indirectly exposed to below ground water, the waterproofing system is faced with aggressive climatic conditions, sulphate attack and chloride induced corrosion. In particular, seawater is made up of a complex array of chemicals that will increase the concrete’s permeability and make it more susceptible to further attack whilst also reducing its protection from the additional sources of deterioration.

Following an initial stage of deterioration, the compromised concrete will then provide additional paths of contamination – in the form of cracks and fractures. No matter how small these penetrations, contaminant ingress will be further accelerated to jeopardise the concrete’s integrity and dramatically reduce its service life.

With traditional basement waterproofing the key requirement is to keep water out. However, with a dry internal environment and the external environment remaining wet, the risk of sulphate attack is increased. Due to groundwater sulphates refreshing the reactionary process, concrete composition and microstructure changes cause extensive cracking, expansion and loss of bond between the cement paste and aggregate, leading to an overall loss of concrete strength.

Although continuous developments and innovations in concrete production have created an improved resistance to aggressive ground conditions, without a waterproofing solution the concrete will never be immune from its harmful effects. Concrete can only be fully protected if water infiltration is prevented entirely – with the waterproofing membrane stopping corrosion before it can begin.

A proven solution
Designed with synthetic adhesive layers combined with a robust HDPE film, Grace Construction Products’ Preprufe provides a permanent physical barrier that protects the concrete from the salt and sulfates found in the sea, ground and environment on coastline locations. Unlike other waterproofing solutions, Preprufe ensures the structure remains unaffected by salt and sulfate attack even if the concentration changes over time.

Preprufe also eliminates the issue of water migration – water tracking between the membrane and structure – a problem well recognised by industry experts. Once a conventional membrane is breached the whole structure is vulnerable, so when a leak becomes visible it is often a considerable distance from the actual source. This makes leak remediation haphazard and expensive, when a simple Preprufe application would have prevented and cured the problem in one.

Conventional membranes are often sealed to the wrong surface such as mudslabs or blinding slabs and then covered with a protective layer that separates it from the structure, providing paths for water migration as a result of membrane discontinuity. Grace’s patented Advanced Bond Technology™ needs no protective layer and enables concrete to aggressively adhere to Preprufe, forming a unique and continuous intimate seal which prevents any water migration between the waterproofing and the structure and substantially reduces the risk of leaks.

Workmanship is another major factor in obtaining good quality and durable structures and the need for concreting and membrane installation to be supervised by qualified and experienced personnel is of primary importance. Preprufe has been specifically designed to ensure that the structure is enveloped with a continuous layer of protection, isolating the structure from the highly aggressive below ground environment. Installation risk is minimised by using a single layer application with simple and efficient detailing that relies less on human skills, saving time and supervision cost compared to traditional low value systems with poor site productivity.

A watertight base
Built on the shores of the Mediterranean Sea, the new £100 million Museum of European and Mediterranean Civilisations (MuCEM) in Marseille has been designed to deliver exceptional resistance to the challenging and aggressive coastal conditions. Faced with salt water exposure, high water tables and fluctuating temperatures, over 5,000m2 of Grace Construction Products’ Preprufe waterproofing membrane proved the perfect solution to provide watertight protection from below the ground up.

Designed by architects Rudy Ricciotti and Roland Carta, and built by Dumez Sud (VINCI Construction France), MuCEM sits on reclaimed land at the entrance to Marseille’s historical harbour – between a 17th century fort and former cruise terminal. A spectacular 15,000m2 cube covered with a latticework reinforced concrete shell, it is the first national museum exclusively located outside the French capital and marks the year of Marseille as the European Capital of Culture.

Due to its coastal proximity, structural engineers SICA and Lamoureux & Riciotti required a comprehensive waterproofing system which would protect the slab from water ingress, provide protection from salt and sulphates in the ground and preserve the lifespan of the structure. Preventing water penetration and migration around the foundations, the application of Preprufe will protect the development and its collection of over 800,000 photographs, prints and pieces of artwork for many years to come.

To complete the project’s comprehensive waterproofing specification, Grace supplied its Bituthene® LM asphalt-modified liquid membrane to provide a continuous waterproofing barrier system between the concrete slab and diaphragm walls.

No other system on the market better protects a substructure from the harmful effects of water, vapour and gas than Preprufe. It can also be applied on wet concrete and is immediately trafficable after installation without protective layers, which makes for fast and easy installation. In fact, when compared to traditional loose-laid PVC systems, Preprufe is more than five times quicker – with approximately 500m2 laid in one day compared to 60-100m2 of PVC over the same time period.

Preserving and protecting cultural buildings is essential for future generations which is why the successful application of Preprufe perfectly demonstrates the importance of specifying a waterproofing membrane which is fit for purpose, economically and environmentally sustainable and delivers waterproofing performance like no other system on the market.

Grace is a leading global supplier of catalysts; engineered and packaging materials; and specialty construction chemicals and building materials. The company’s three industry-leading business segments – Grace Catalysts Technologies, Grace Materials Technologies, and Grace Construction Products – provide innovative products, technologies, and services that improve the products and processes of its customer partners in over 155 countries around the world.

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