Inverted Flat Roofs

Ravago Building Solutions

The thermal insulation of flat roofs is an important issue both for winter chill and summer heat, ensuring the efficient reduction of outbound heat flows from a structure when it is being heated and significantly reducing the need for air conditioning.

The closed-cell structure design of Ravatherm XPS X thermal insulation is perfect for inverted flat roofs across a range of flat roof applications.

In an inverted flat roof build-up, unlike in a conventional warm roof, the waterproof roofing membrane Ravatherm XPS MK is installed directly on top of the structural deck and is protected by the insulation layers without the need for an additional vapour barrier.

A water-flow reducing layer (WFRL) is placed on top of the insulation which is then held in place by either paving slabs or gravel ballast. The WFRL should not be confused with the waterproofing layer and this essential component minimises heat loss due to the rainwater cooling effect.

Ravatherm XPS X is suitable for a range of conventional inverted flat roofs:

Green roofs
Vegetation is used as the ballast, reducing the load on the rainwater drainage system, delivering a better heat balance on the roof, creating an excellent microclimate and providing considerable carbon dioxide binding ability.

The lower load provided by vegetation means this is an excellent solution in both a technical and ecological perspective.

Blue roofs
Water retention systems incorporated into a green or conventional roof store water for a short period, slowly releasing water to the sewer system in a controlled way, removing a potential cause of flash flooding following a severe storm. This is also known as SuDS (Sustainable urban drainage system) and is becoming more and more common in urban areas.

Roof terraces
Designed to be accessible to pedestrian foot traffic using decorative paving bedded in a screed or overlaid with paving slabs on spacers. The structure may also accommodate vegetation in planters or shading structures.

Car park decks
Constructed to accommodate the high loads generated by vehicles moving and being parked on a paved surface. Rooftop parking is a practical way of utilising the often large, flat surface roof area of commercial buildings, such as shopping centres, and residential buildings, where land area is at a premium.

To learn more, please visit the E-Learning: Introduction to Ravatherm XPS X module.


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Ravago Building Solutions

Ravago Building Solutions

Ravago Building Solutions is the largest producer of extruded polystyrene (XPS) insulation in Europe, manufacturing the market leading Ravatherm XPS X range.

Ravatherm XPS X products are made and despatched from King’s Lynn in Norfolk,...
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