The almost-invisible, multi-function wall weep for discharging water from external walls. Suited for use with the Timloc cavity tray system, over external lintels and on external masonry walls. Invisiweep has numerous patent-pending innovative features, including a venturi effect outlet tube that reduces water pressure, allowing for optimal drainage.

Invisiweep satisfies all NHBC requirements and meets British standards: BS5250, BS5628 and BS8215.

The 500mm Invisiweep extension provides the ideal solution for render and wide walls and can be easily cut to size on site.


  • Any situation where water must be discharged from an external wall, including:
  • At ground floor slab level
  • Within cavity tray systems
  • Over external lintels
  • On external masonry walls

Add the Invisiweep to your specification on NBS or SpecifiedBy

Add the Invisiweep Extension to your specification on NBS or SpecifiedBy

Product Information


HeightWidthLengthColourBox QuantityProduct Code

State required colour at the end of the required product code: TE:Terracotta BU:Buff BR:Brown CL:Clear WH:White GR:Grey BL:Black BB:Blue Black


HeightWidthLengthColourBox QuantityProduct Code

  • Integral 4mm vermin barrier and rainwater baffle as recommended by BS5250, to reduce ingress of large nest building insects, mammals, and rainwater penetration to the cavity.
  • External ribs & tapered profile, to key into mortar for secured fixing.
  • Full height upstand to cavity side, to maintain drainage and minimise the impact on blockage from cavity cement build up.
  • Discrete water outlet, to minimise the impact and reduce visibility for a truly concealed wall weep.
  • Venturi effect outlet tube to reduce pressure, allowing for optimal water drainage.
  • Extension tube available for wide walls and render – IW500EX.
  • Cavity wall weeps or cavity drain units should always be installed in cavity masonry walls to allow drainage at regular intervals. They are required at ground floor, below DPC level, and must also be provided as part of any cavity tray run, including roof abutment trays, over lintels, and continuous cavity tray systems, such as gas protection barrier systems.
  • Unfortunately, many sites are still providing a weep hole facility by simply leaving the perpend joints between bricks open, these open joints are prone to being filled.
  • Perpendicular joints left open can be very noticeable and result in an infestation of nest building insect and small mammals and allow the ingress of driving wind and rain, which leads to the need for a proprietary weep unit such as the InvisiWeep.
  • InvisiWeep has been designed and flow tested to optimise the discharge of water while meeting the requirement for a small, concealed outlet size.
  • Manufactured to BS EN ISO 9001 and BS EN ISO 14001
  • Meets British standards; BS5250, BS8000, BS5628, BS8215
  • Satisfies all NHBC requirements
  • Complies with all relevant Building Regulations

Injection moulded from Polypropylene.

Invisiweep is available in a choice of:

  • Clear
  • Terracotta
  • Buff
  • Brown
  • Grey
  • Black
  • Blue/Black
  • White
  • Invisiweep should be used in perpendicular joints to perform the function of a drainage channel wherever water could collect inside a cavity wall such as over external lintels, or over cavity trays.
  • To work effectively the Invisiweep should be placed directly on top of the base of a cavity tray, DPC or on the front edge of a lintel.
  • Wall weeps should be placed at 450mm centres above openings with a minimum of two to comply with NHBC recommendations.
  • Care should be taken to ensure the Invisiweep is kept clear of mortar and does not become blocked. This is important at the cavity side of the weep which could be blocked by mortar droppings from above.
  • For wide walls and render finishes, the weep tube extension can be pushed into the open end of the Invisiweep and cut to the required size.
  • To calculate quantities, divide the overall length of the cavity tray, DPC or lintel by 450mm and round up to the nearest number or by 900mm if wider centres for perimeter cavity trays.
  • Allow a minimum of two Invisiweeps per opening and one InvisiWeep for every cavity tray stop end.
  • The InvisiWeep is 102mm long and will cover a standard external wall, longer units can be made up on site with additional IW500EX weep extension.
  • State the product number with box quantity and colour.

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