RTV250CL – Rytons Retro Weep Vent

General Details

RTV250CL – Rytons Retro Weep Vent

  • Retro-fitted cavity ventilator and weep hole duct for new build or refurbishment.
  • Easily retro-fitted through a 25mm dia. drilled hole.
  • Ideal solution when no provision has been made for cavity venting or weeps or an insufficient number have been installed.
  • Front louvres protect against rain and large insects.
  • Flange aids positioning, helps prevent seepage and covers drilling for a neat finish.
  • External fins provide a lock-tight fit.
  • Clear colour blends with any facing brick or render to maintain the aesthetic appearance.
  • Use in timber frame and traditional build.
  • PLEASE NOTE: This item is a plastic component and therefore not suitable for use within the external walls of high-rise buildings requiring non-combustible materials, i.e. those 18m high or more complying to Regulation 7(2) and Approved Document B, and those 11m high or more complying to 2.7 of Building (Scotland) technical handbook 2019.  For compliant alternatives, which includes our tailor-made design service, see Rytons A1 Fire-rated Ventilation Range.


  • 80mm L (excluding flange) x 26mm Dia. (including fins) (see image gallery above).
  • CAD drawing available by email.

Free Area:

  • 250mm² per unit.


  • Clear.


  • Polypropylene.

Installation – General:

  • Drill a 25mm dia. hole through the external leaf at a slightly upward angle.  Position the front louvres horizontally using the ‘top’ marker on the flange as a guide.  Firmly push Rytons Retro Weep Vent into the pre-drilled hole, ensuring that the front louvres are kept horizontal at all times, until the external flange sits tight and flush with the wall (may be tapped lightly into position using a rubber mallet).

Installation – Cavity Venting:

  • For cavity ventilation space according to current regulations at the top and bottom of the cavity wall to ventilate the cavity and assist in the drying out of the wall.  Lower ventilators should be placed below the dpc, unless cavity trays are used when they should be positioned above the tray.  Vertically stagger vents when placing them above and below horizontal fire stops.
  • Install at 462mm centres to NHBC Standards 6.2.  Ventilation openings should be equivalent to open brick perpends every 1.2m (i.e. 650mm² free air every 1.2m).  These openings can also provide drainage of the cavity.
  • Install at 1m centres to The Building (Scotland) Regulations – Domestic.  Masonry outer leaf 3.10.6.  Where the outer leaf is a masonry construction, cavities should be vented to the outside air by installing ventilators with at least 300 mm² free opening area at 1.2 m maximum centres.  Precipitation, i.e. rain, snow and sleet, can penetrate the outer leaf of an external wall and cavities are normally drained through weep holes.  These weep holes can also provide the necessary venting.
  • Also, refer to British Standards BS 5250.

Installation – Weep Hole Ducts:

  • As weep hole ducts space every fourth brick to drain cavities above and below the dpc, and above lintels and cavity trays.  At least two weep holes should be provided over an opening, i.e. lintel.
  • NHBC Standards 6.1.17.  Where fairfaced masonry is supported by lintels weep holes should be provided at a maximum of 450mm intervals and each opening should have at least two weep holes.
  • NHBC Standards 6.11.7c.  Rendering shall be detailed to ensure appropriate weathertightness and durability.  Issues to be taken into account include … c) weepholes.  Weepholes should be provided: „„where required for ventilation to timber frame construction; „„to the last tray at stepped abutments; „„in severe or very severe exposure zones where rendering is returned back into the window or door head (weepholes are not required where the render is not returned); „to cavity trays on parapet walls.
  • The Building Regulations, Approved Document C, internal and external walls (moisture from the ground). 5.5 (b) If the wall is an external wall, the damp-proof course should be at least 150mm above the level of the adjoining 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.
  • Also, refer to British Standards BS 8215.

Handling Information:

  • Box quantity: 50 number.
  • Box size: 28cm W x 11cm H x 14.5cm D.
  • Box weight: 0.5kg.

NBS Specification:


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

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