The Number One enemy of every building is water. On external surfaces it can leave ugly stains or efflorescence, and if it penetrates the structure, internal damage is sure to follow. The solution is to cover exposed top surfaces with a coping. Here we’ll explain why aluminium coping is often the best choice.
Walls and Wall Coverings
Practically every modern flat-roofed building incorporates a parapet wall. In addition, many older buildings – particularly terraces – have parapet walls separating the roofs of adjoining properties.
A parapet wall is an extension of the exterior or dividing wall that extends up above the roof. On flat-roofed buildings this hides roof-mounted equipment and creates a more attractive appearance. These parapets are generally horizontal, unlike those often used between terraced properties. On these, the wall is often pitched at the same angle as the roof itself.
Water naturally runs off a pitched parapet wall. Horizontal walls need an angled surface to achieve the same effect. In both cases, the coping directs water away rather than letting it rest on, and probably penetrate into, the wall itself.
Wall Covering Problems
If there’s no coping, water will rest on the top surface and soak in. This is a particular problem with brick walls as bricks are porous. Mortar joints also create opportunities for water ingress. With a flat roof it’s feasible to take the waterproof membrane up over the top of the wall, but this is often unsatisfactory, for two reasons:
Sunlight and temperature fluctuations can crack areas of membrane that were stressed and stretched during installation.
Securing the membrane to the outer surface of the wall results in an unattractive appearance.
On brick walls water ingress can lead to efflorescence. This is a white powder, (actually a form of salt,) that stains the outer surface. A more serious problem that shows up as so-called rising damp is when water soaks down through the wall. Eventually it can lead to plaster or rendering coming away and rot or corrosion in structural components.
Sloping the top surface of the wall helps avoid these problems but then the water runs down the sides. This produces unsightly staining and may even lead to mould or lichen. On the inner surface, or the dividing wall between terraced properties, this water could penetrate the structure and cause mould and structural damage.
Solution: Aluminium Copings
How to solve wall covering problems with aluminium copings? Aluminium copings with a domed or sloped upper surface cover the top of the wall and direct water away. In addition, by incorporating drip guards on the underside where they overhang the wall, they stop water running down the sides.
Waterproof joints between individual sections of aluminium coping keep water out while allowing for expansion and contraction. Secure attachment to the wall is essential to guard against high winds. Various fixing options exist but Secret Fix copings provide a clean and attractive finished look.
HJA Fabrications: Your Source for Secret Fix Copings
Our lightweight and durable aluminium coping is available in a wide range of finishes and colours and has been installed on many different buildings around the UK. Contact Us for more information.
