Basement Waterproofing Pumps

Type C waterproofing provides drained protection. A profiled membrane is fixed to the inside of the basement walls and floor, creating a cavity behind it. Any water entering the structure flows freely through this cavity to a sump, where a pump removes it.

That water is channelled through perimeter drainage to a sump, where a pump removes it to a suitable discharge point.

Cavity drain systems are a popular retrofit choice for older basements and cellars, and are increasingly specified in new builds creating habitable space below ground. They are particularly common in basement conversions under high-value urban property, where the additional floor area justifies the cost of waterproofing the structure correctly.

The single most popular pump we supply for Type C cavity drain systems is the AMA Drainer 301. It is a 230V automatic submersible pump fitted with an arm-style float switch, which is well suited to the narrow sump chambers typical of domestic cavity drain installations where pendant floats can foul against the chamber wall. The pump has a maximum head of 6.5 metres, which is suitable to lift water from a basement sump up to a ground-floor or external discharge point in the vast majority of UK homes.

It handles solids up to 10mm, has thermal overload protection, and includes an integrated non-return valve on the 1¼" outlet.

The AMA Drainer 301 can be installed into a sump chamber that has been formed as part of the cavity drain works, with the membrane and perimeter drainage discharging into it.

Alternatively, a complete packaged pump station can be installed, which is often the simpler route for retrofit projects.

Packaged pump stations arrive as a single sealed unit comprising the chamber, the pump (or pumps), the float switches, the inlet connections and the discharge pipework, ready to be set into the floor slab.

They remove the need to form a watertight sump on site and they make pump servicing far more straightforward later in the building's life.

For most domestic basement waterproofing projects we recommend the FPS Iguazu 635 Packaged Pump Station, which uses a single AMA Drainer 301 within a 635mm chamber.

Where redundancy is required, either because of higher water volumes or because the basement is in continuous occupied use, the FPS Iguazu Twin Packaged Dual Pump Station houses two pumps in a duty-standby arrangement, so a single pump failure does not put the property at risk.

Although a Type C cavity drain system handles clean groundwater rather than foul water, we recommend specifying a recessed and sealed manhole cover over the sump chamber.

A solid sealed cover prevents any musty or damp odours from the sump rising into the basement living space, which can otherwise become noticeable in warm weather or where the chamber sits below an occupied room.

The recessed top tray also allows the cover to be tiled, carpeted or finished to match the surrounding floor, which matters in a converted basement that is being used as habitable space.

It is worth noting that basement waterproofing does not have to be Type C alone.

BS 8102 also covers Type A (barrier waterproofing using tanking slurries and applied membranes) and Type B (water-resistant concrete construction).

Many waterproofing designers will specify a combination of two systems, particularly on high-risk sites or where the structure is being used for habitable space.

Whichever waterproofing types are specified, a packaged pump station is almost always included in the design to capture and remove any water that does enter the structure. Even on a fully tanked basement, a sump and pump provide a vital last line of defence against pinhole failures, blocked external drainage, or rising groundwater levels.

The supply of pumps and packaged stations is one part of a basement waterproofing project. The engineering design behind the system, including discharge route assessment, sizing of the pumps to peak ingress rates, and integration with the existing surface water or foul drainage, sits outside the scope of a pump supply order. Our case study blog When Free Advice Isn't Free sets out why this engineering input matters and what can go wrong without it.

For projects that require formal design input, this is delivered by our sister company FPS Environmental, either as a drainage review for existing or proposed installations, or as a full drainage design for new schemes. This is particularly relevant on listed buildings, projects requiring Building Control sign-off, or sites where the proposed discharge point is shared with a public sewer.

Although this page is framed around basement waterproofing, the same products and principles apply to a wide range of below-ground applications. Lift pits, lightwells, vaulted cellars under pavements, plant rooms below ground level, and converted coal stores all benefit from the same combination of cavity drainage, sealed sump and reliable submersible pump. The AMA Drainer 301 and the Iguazu packaged stations cover the vast majority of domestic and small commercial below-ground projects.

Our standard range covers the great majority of residential basement waterproofing requirements. For projects that fall outside this, whether because of unusual ingress volumes, restricted access, deep installations or specific specification requirements from a waterproofing designer, we can create bespoke packaged pump stations to suit the project. Please get in touch with the technical team with the design brief, the proposed sump location and the discharge route, and we will scope the build accordingly.

For bespoke packaged pump station enquiries, send us the project brief below and our technical team will be in touch. Please include the proposed sump location, expected ingress volumes and the discharge route where known. Contact us for technical specification on larger projects.