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.
Inverted flat roof insulation.
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.
Inverted roofs are a type of warm flat roof where the insulation is above the waterproofing layer.
A the permanent protection of the waterproofing membrane of the overlying layers from factors such as solar radiation extreme temperature variations mechanical stresses etc.
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.
However there are other products on the market such as enertherm xps plus which outperform traditional xps boards.
Rigid extruded polystyrene insulation has minimal water absorption due to its closed cell structure.
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.
Project specific proposals or solutions are.
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.
An inverted roof is quite simply where the waterproofing layer is installed over the structural deck rather than over the insulation.
Benefits of inverted roofs.
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 main advantages of the inverted roof insulation with ballast are.
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.
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.
