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Newton NewSeal 408 Deck Drain 2m x 20m

£292.00 Ex VAT
£350.40 Inc VAT

Newton 408 membrane designed for deck and flat roof drainage.

Newton Deck Drainage Membrane

Newton NewSeal 408 DeckDrain membrane is a highly effective deck and flat roof drainage layer. It is designed to be installed above decks and flat roofs.

DeckDrain is double cuspated - which means it has drainage studs both on the upper and lower surfaces. The double cuspated design provides two layers of drainage and prevents water getting trapped above the deck membrane. 

Newton’s DeckDrain HDPE membrane also features an in-built geotextile layer that acts as a filter. This ensures fines don’t cause an issue with drainage. 

Uses of Newton DeckDrain

Newton NewSeal 408 DeckDrain provides a drainage layer above a deck, balcony or flat roof waterproofing membrane. 

It can be used in the following applications:

  • Under block paving or flooring slabs that have been bedded on sand.
  • When soil-filled planters are added to the deck or flat roof.
  • When an intensive green roof is installed on the deck or flat roof.

It is also suitable for use as a vertical drainage layer when used as part of a professionally designed and installed externally applied basement waterproofing system.

Installing 408 DeckDrain membrane

The Newton deck drainage membrane should be installed directly above the primary deck or roof waterproofing membrane. Start by rolling out the Newton DeckDrain membrane with the geotextile surface facing up. Cut the drainage membrane to length using a utility knife or shears.


When adding subsequent lengths of membrane, roll them out adjacent to the previously rolled out lengths to form simple butt joints. You do not have to overlap the membranes using the dimples.

However, if you would like you to form a stud-into-stud joint you can overlap the membrane sheets. In order to achieve this joint, you will need to remove some of the geotextile layer from the already laid membrane. This joint can then be taped with Newton Waterseal Tape if required.

Drainage Outlets

You will need to ensure that the 408 DeckDrain leads into the double entry drainage outlets. The membrane will not need to be sealed however the drainage outlets will need to be maintainable and protected from blockages. There is no need to seal to outlets or protrusions through the membrane.

The membrane can be connected to other membranes that may be used in the waterproofing scheme such as Newton 410 Geodrain. There is no need to lap 408 DeckDrain up vertical interfaces.

Deck Drainage Design

When considering deck and flat roof drainage design, your solution needs to be able to comfortably dispose of the expected rainwater. You will need to have suitable drainage outlets. These elements should be part of your deck drainage design as well as ensuring the required fall is achieved. The fall design should be 1:40 to ensure a finished fall of at least 1:80.

  • Concrete construction -  it is best to have the fall created when the concrete is installed. If this isn’t possible, the required fall can be formed with a screed retrospectively.
  • Timber construction - with timber roofs and decks, the timber frame should be constructed to the correct design fall.

Permagard - Providing Solutions. Inspiring Confidence.

If you have any questions about deck or flat roof waterproofing, which membranes to use or the best drainage solutions please contact our experts. Click through for more Newton Waterproofing Products.


  • Quick and easy to install
  • Provides a clear drainage path for surface water to roof drainage outlets
  • Double cuspated design
  • Part of a flat roof waterproofing solution
  • Polypropylene geotextile layer filters out fines
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