Underlays and Membranes, Estimating Guide

 

Decra 300 High Performance Underlay (50m x 1m roll)
Cover per roll:    45m² (approx. at 100mm lap)*
                             42.5m² (approx. at 150mm lap)*
                             38.7m² (approx. at 225mm lap)*
                             35m² (approx. at 300mm lap)*

*no allowance made in the above coverage’s for side laps and any wastage.

Ready Reckoner
For Decra Classic, Plus Tile, Elegance and Parctile: Multiply the number of tiles ordered by 0.011*.
For Decra StratosTile and Oberon: Multiply the number of tiles ordered by 0.010*.
Example: Project requires 1000 Decra Classic: 1000 x 0.011 = 11 rolls underlay needed.
*Assumes Decra 300 underlay has a horizontal lap of 150mm and allows for an average percentage of on site wastage.

 

Decra TwoF Economy Underlay (30m x 1m roll)
Cover per roll:    27m² (approx. at 100mm lap)*
                             25.5m² (approx. at 150mm lap)*
                             23.25m² (approx. at 225mm lap)*
                             21m² (approx. at 300mm lap)*
*no allowance made in the above coverage’s for side laps and any wastage.

Ready Reckoner
For Decra Classic, Plus Tile, Elegance and Parctile: Multiply the number of tiles ordered by 0.022*.
For Decra Stratos and Oberon: Multiply the number of tiles ordered by 0.019*.
Example: Project requires 1000 Decra Classic: 1000 x 0.022 = 22 rolls underlay needed.
Assumes Decra TwoF underlay has a horizontal lap of 150mm and allows for an average percentage of on site wastage.

 

Decra 700 High Performance Breather Membrane (50m x 1.5m roll)
Cover per roll:    70m² (approx. at 100mm lap)*
                             67.5m² (approx. at 150mm lap)
                             63.75m² (approx. at 225mm lap)
                             60m² (approx. at 300mm lap)*
*no allowance made in the above coverage’s for side laps and any wastage.

Ready Reckoner
For Decra Classic, Plus Tile, Elegance and Parctile: Multiply the number of tiles ordered by 0.007.
For Decra Stratos and Oberon: Multiply the number of tiles ordered by 0.006.
Example: Project requires 1000 Decra Classic: 1000 x 0.007 = 7 rolls Breather Membrane needed.
Assumes Decra 700 Breather Membrane has a horizontal lap of 150mm and allows for an average percentage of on site wastage.

For further information on Decra's range of high performance underlays and membranes please click on the link below.
Underlays & Membranes

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