Newton 420 Reservoir Green Roof Drainage Membrane – 0.97m x 50m

Newton 420 Reservoir is a unique drainage and water-retention membrane for use where a water reservoir is required for extensive green roofs of sedum, herbaceous plants, mosses or grass above decks and roofs.

Unlike other products of this type, 420 Reservoir has a bonded geotextile that prevents intrusion of the soil into the water holding cups during back-fill and compression. This results in a permanently larger volume reservoir than any other 20mm-deep green roof membrane. 

When the water holding cups are full, the large drainage holes within the HDPE core allow water to easily pass through to the drainage layer below to prevent saturation and waterlogging of the green roof above. 

Key Benefits 

• Unique bonded geotextile does not sag into the water holding cups as is the case with loose laid geotextile. 
• Large drainage holes allow a much higher drainage flow through the membrane than comparative products, ensuring that when the water holding cups are full, the water drains quickly so as not to waterlog the soil. 
• Suspended soil particles (fines) are filtered out by the geotextile layer. 
• Large drainage layer created by the 20mm HDPE core. 
• Tough and durable. 
• Quick and easy to install.

Typical Applications 

• As a water holding and drainage layer above a deck, flat roof or pitched roof where shallow planting is used to create an extensive green roof.

Limitations: 

• Should not be used as an intensive green roof membrane. Please use 408 DeckDrain together with 409 Root Barrier
• Do not mechanically fix through drainage layers where waterproofing beneath can be punctured 
• Sufficient load above membrane is required to prevent wind lift. Please consult a specialist.