Flat roofs: a new minimalism or stylistic laziness?




Flat roofs: a new minimalism or stylistic laziness?

Flat roofs seem to be making a comeback in contemporary housing. So much so that they seem fashionable at the moment. Is there a debate here or not?

I should make one thing clear from the outset: we are strong supporters of sloped roofs for technical reasons and because we know how much they contribute to architectural diversity.

We think several factors explain the revival of the flat roof.

It seems that the quality of products currently used has considerably improved, as have the conditions in which they are installed. It is true that the durability of membranes and flat roof complexes has improved, however, they are now sold at prices that are comparable to and sometimes even higher than traditional dry roofing.

Nowadays, if flat roofs are popular for individual housing and in urban areas, it is because of their versatility. Gravel flat roofs, green roofs, roof terraces… a broad range of possibilities that make flat roofs an extension of the house rather than a wasted surface.

Environmental added-value is another reason flat roofs are becoming popular again. Theoretically, they can ensure less heat loss. This means they require less “material” for insulation and watertightness, as well as for the building frame.

Flat roofs are also considerably easier to install, and therefore theoretically more cost-efficient.

Lastly, this type of roof can be easily equipped with thermal or photovoltaic solar panels to produce energy.

Why do we support sloped roofs?

The slope is part of the collective unconscious. Just ask a child to draw a house. Even if he lives in a tower block he will draw a triangular roof with a smoking chimney placed perpendicular to the slope. For the majority of us, the sloped roof is reminiscent of the attic and its mysteries. It is a room to discover, or to live in when it is converted with skylights or dormer windows. A room from which to safely observe the world below.

In most European countries, the dominant use of sloped roofs is related to the historic use of small elements such as tiles or slates, which require a slope to ensure watertightness and durability of the roof. Sloped roofs are also related to the wooden frame tradition, which also uses local resources.

But above all, it is our obsession with controlling rainwater runoff that makes us eternally continue to plead in favour of the sloped roof! This is an industrial’s preoccupation, but it is shared by architects and roofers, and it is the common denominator that justifies our offer of zinc products for roofing and facade.

We know rainwater well. In our “rain and wind” stations, we know it is ruthless and observe its groundward race from ridge caps to gutters. We have learnt how to adapt our strategies, not to stop it but to channel it. Because rainwater has time on its side. A silicon joint or glued bitumen layers will inevitably end up leaking. This is why our eave coursing serves a double purpose. On the surface, it lets a little water through, which, with no pressure, is then directed into folded grooves that channel it downwards to the bottom of the slope. No joints, no soldering, just a discreet, effective zinc assembly.

But rest assured, it is not our intention to criticise flat roofs. They can be useful, especially for industrial or commercial buildings. They also provide diversity to ensure variety in our urban skylines.

We just wanted to recall the importance of the slope in the durability of roofing.

Roger Baltus
Engineer - Architect
VMZINC Communication Director

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