Vaults and Tunnels

Experience

CCL has vast experience in designing, waterproofing and tanking the more complex shapes like vaults, tunnels, and arch structures, whilst also providing a stunning finish to a project. When providing the waterproofing or tanking to create the dry and functional habitable (or non-habitable) space, the devil really is in the detail. Installing membranes to curved spaces really does need extra time, effort and thought applied. If you follow this principle, the outcome will look incredible and function outstandingly well.

With space becoming such a premium (especially in the capital), historical coal vaults in London have often been left dormant for years; owners are now looking to turn these areas into storage, wine cellars and habitable areas, including shops, living spaces, offices and plant rooms etc.

Projects

CCL has been fortunate to be involved in some fantastic projects where disused railway arches have been turned into boutique shops, public gymnasiums and restaurants, and in some instances, keeping some of the beautiful curvatures and features of the vaulted ceilings to give a finish that is simply stunning!

Over the years CCL has explored many different waterproofing methods and techniques for tackling waterproofing of below ground vaults, and would now always recommend that ‘type C’ internal water management type systems are the most appropriate method.

The other methods commonly seen installed in vaults are internally applied waterproof renders and cementitious waterproof coatings.

In our experience these do not always prove effective as the integrity of the substrate (crumbling brick) is not normally sufficient to bond on to, and because of movement exerted on the vaults from above, these can be susceptible to cracking the membrane. Together with surface rainwater, that is able to percolate through from the ground above, these are generally deemed as high-risk waterproofing elements.

It is much better therefore to accept water will enter through the structure and manage it with a fully maintainable cavity drain membrane system, removing water via mechanical sump pump systems or via suitable gravity fed clean water drainage gullies.

It is important to note that CCL would always recommend that a totally independent structure is installed in front of the cavity drain membrane to ensure it is fully supported throughout the lifetime of the membranes used. Also, to minimise the number of fixings made through the cavity drainage sheet to increase the effectiveness of the membrane.

This is especially essential if there is no fall to under pavement basement vaults where the fully independent structure will need to be installed to provide a fall on the membrane. This is crucial to ensure that water flows behind the membrane and directly behind the vertical membrane, thus keeping the it fully supported and ensuring the water management system, as a whole, works efficiently for the entirety of its working life.