City centres are overcrowded with vehicles and restricted areas, car parks are “stressed” and there are never enough spaces to go round. Alongside the more “standard” trafficable ceiling slab solutions — such as in the case of underground garages — it’s not too much of a stretch, where structurally feasible, to think about designing or making better use of spaces on elevated levels.
Over the holidays, car parks on the roofs of public buildings or buildings for use by the public could also provide refuge for the cars of passers-through. During the offices’ closing time, for example, these parking spaces can become a real asset, an ideal solution for making use of otherwise unused space and increasing the number of car parks for people travelling to tourist hot spots
Continual vehicular traffic and exposure to the elements — from freezing temperatures to sweltering heat — mean the construction materials used must be fit for purpose. Intensive use means it’s imperative all the proper layers are in place (build-up design) to serve the different specific functions. Let’s see what these layers are.
What do we need to be careful about when designing a rooftop car park?
This kind of roof is subjected to high loads, both static and dynamic, from vehicles of all kinds. This makes the mechanical protection of the waterproofing layer and the need for high compressive strength two key focus areas.
Drainage is another aspect to be factored into the design. Rainwater can seep into the underlying layers and damage them, so we need to ensure that water is drained off the roof properly.
We recommend applying studded membranes laminated with nonwovens or drainage geocomposites made from monofilaments or geonets.
Our drainage geocomposite T-Mix Drain Plus is a good candidate for the drainage layer. Alternatively, you can opt for the T-Net Drain 5 and T-Net Drain 7 geonets, which are sandwiched between nonwovens.
The job of mechanical protection, together with drainage, can instead be handled by the drainage geocomposite TMD 1011. The product consists of a filter geotextile laminated to a studded membrane, whose conformation delivers effective drainage even under the strain of high loads (up to 400 kPa).