An inverted roof also referred to as a protected membrane or upside down roof is form of flat roof in which the waterproofing layer is beneath the thermal insulation rather than above it.
Inverted flat roof insulation.
Inverted roofs are a type of warm flat roof where the insulation is above the waterproofing layer.
An inverted roof is quite simply where the waterproofing layer is installed over the structural deck rather than over the insulation.
The standard design consideration is that the rain falling on the roof filters through the ballast and between the insulation boards until it reaches the membrane and then drains away through rainwater outlets.
Benefits of inverted roofs.
This makes it the only material suitable and approved for inverted roof applications.
The great benefit of inverted roofs is that the insulation protects the membrane from extremes of weather such as frost uv exposure and the expansion and contraction that comes about from summer winter temperature cycles which can be as much as 80 c on some roofs.
The only point of putting the insulation on top of the waterproof membrane is when you can t take it off as when for example it is bitumen.
The added benefit of this type of roofing is that the membrane is also protected from expansion and contraction caused by changes in the weather and temperature.
It is worth considering that standard xps and eps inverted roof insulation is not as thermally efficient as pir insulation when used as part of a standard warm roof design.
Foamglas inverted roof systems inverted roof with non combustible insulation on a continuous support foamglas invatherm loose laid double layer system 2 4 system 4 8 3 7 8 schematic drawing 9 5 solutions for technical details and specification clauses can be provided on request.
Rigid extruded polystyrene insulation has minimal water absorption due to its closed cell structure.
The inverted roof insulation protects the membrane from extremes of weather such as frost uv exposure and the expansion and contraction that comes about from summer winter temperature cycles.
This means that the insulation should be highly resistant to water absorption for example an extruded polystyrene based product which will not be affected by water or repeated freeze thaw cycles.
Ravatherm xps x has been created specifically for inverted roofs a form of flat roof where the thermal insulation is placed above the waterproof membrane.
Insulation can either be put below the weather proof membrane which is called a warm roof deck construction or above the waterproof membrane which is called an inverted warm deck.
The main advantages of the inverted roof insulation with ballast are.
