Sealing off Disused Drains


DRAINBLOCK BAG™ is a system which allows a disused lateral to be sealed off, remotely, at the point where it joins the downstream drain or sewer.

The system uses a twin fabric bag containing an expanding polyurethane resin foam, and is based on the FOAMBAG™ technique which the company initially developed some 35 years ago for use in the gas distribution industry.

Drainblock Bag

The major advantage of the DRAINBLOCK BAG™ is that it is positioned from an access point up to 15 metres away from the joint with the main. This avoids the need to excavate in the highway – a particular benefit at busy junctions and other sensitive locations.

DRAINBLOCK BAG™ prevents ground water from entering sewers, stops the passage of odour and discourages the movement of rats and other vermin. The entire lateral can be filled behind the bag, if required, thus avoiding unauthorised connection to clean water drainage systems.

For use on clay, concrete, ductile, and plastic pipes. Kits are available for sealing off 100mm/4” and 150mm/6” diameter pipes. Other sizes available to order.


  • Prevents ground water entering sewers
  • Avoids unauthorised connections with abandoned pipes
  • Stops the passage of odour or airborne particles
  • Discourages the movement of rats and other vermin


A cross sectioned view of a cured Steve Vick RATBLOCKTM bag in Perspex pipe, showing the porous restraining bag in the centre and articulated steel plate membranes at the entrance of the pipe.

Disused drains and sewers offer ideal harbourage to rats and frequently offer a route for them to move between sewers and the surface. Current UK Building Regulations stipulate that when work is carried out which results in any part of a drain becoming permanently disused, the drain must be sealed.
The regulations also demand that drains or sewers less than 1.5m deep which are in open ground should be removed and that other pipes should be sealed at both ends and at any point of connection and filled to ensure that rats cannot gain access. Larger pipes (225mm and above) should be grout filled to prevent subsidence.

Available in kit form, the system uses expanding polyurethane foam contained within a bag, incorporating two articulated steel plate membranes. Once cured, the foam provides a water, odour and gas tight seal within the pipe while the steel membrane prevents the passage of vermin.

RATBLOCK™ Bags are ideal for sealing off these drains and sewers to comply with Building Regulations and prevent the passage of rats and other vermin.


  • Application is carried out remotely
  • Cost effective
  • Allows laterals to be sealed off at point of joining the main – ideal for use on relocated WC’s
  • Certified by WRc as vermin, water and odour proof
  • Installation is quick and easy – only taking 30 minutes for the foam to cure