June 7, 2024

Tech Talk: Rytons Rytweep® Clear

Rytons Rytweep® Clear

Small but mighty in the prevention of damp in cavity walls

Rytons Rytweep® perpend cavity weep hole ducts are essential components in the construction of external masonry walls. Positioned above cavity trays and DPCs, they provide vital drainage outlets, allowing accumulated moisture to escape. This prevents the transfer of water to the inner leaf, which can lead to damp problems.

The Building Regulations, Approved Document C, Internal and external walls (moisture from the ground)

5.5(c) If the wall is an external cavity wall provide weep holes every 900mm to assist in the transfer of moisture through the external leaf. Where the damp-proof tray does not extend the full length of the exposed wall, i.e. above an opening, stop ends and at least two weep holes should be provided.

NHBC Standards 6.1.17

Weepholes to cavity walls should be provided:

  • to cavity trays above openings and penetrations through the wall (such as sub-floor vents, ducts, or flues), at least two per opening at not more than 450mm centres
  • at least one to the bottom tray in a series of stepped cavity trays, eg at pitched roof abutments
  • on cavity trays in parapet walls or at horizontal roof abutments at not more than 1m centres
  • to cavity trays above inset gas meter boxes, a minimum of 180mm from the edge of the meter box at not more than 1m centres.

Paired with its tapered design, the transparency of Rytons Rytweep® Clear allows it to blend perfectly with any colour brick or mortar for a weep that is virtually invisible when installed. Clear saves time by eliminating the need to work out colour splits. Clear saves money by ordering one colour rather than several. Clear reduces waste by using extras on other phases rather than discarding them. Clear looks good and gives continuity throughout the development.

  • Renowned tapered design allows efficient water release and makes it virtually unnoticeable when installed.
  • Lugs help grip mortar for secure installation.
  • Full brick height at the rear to prevent blockage and ensure the best possible drainage.

How to we get the Rytweep® ultra-clear? By investing in high quality tooling that can run high quality plastic. Milky white weeps are a giveaway for lower grade plastic. So, even though the Rytweep® clear looks like glass, it’s high quality plastic which can easily withstand the rigours of site life.


Goodbye, colour matching! The ultra-clear finish blends perfectly with any colour brickwork or mortar.


Easy to specify. Easy to order.
Easy to handle on site.


The preferred weep for major house builders and bricklayers as part of their national trade specifications.

Mid-rise and low-rise buildings 11m high or less: External wall surfaces less than 1m from the relevant boundary are required to have a reaction to fire performance of B-s3, d2 or better. Read more.

Use Rytons alternative A1 Fire-rated Metal Rytweep®

For further information, or to discuss cavity weep requirements, please do not hesitate to call our technical sales office on 01536 511874 or email admin@rytons.com.

Rytons is proud to be a family run business and British manufacturer since 1972
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