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Cavity Drain Membranes

Modern Type C waterproofing for reliable water management.

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The Modern Solution in Suffolk, Norfolk & Essex

Cavity Drain Membranes (Type C Waterproofing) are widely considered the safest and most reliable way to waterproof a basement, especially for conversions into habitable space.

Unlike tanking, which fights the water pressure, a membrane system accepts that water will penetrate the structure. It uses a high-density polyethylene (HDPE) studded sheet to create a cavity between the damp wall and the internal finish. Water runs down behind the membrane into a drainage channel and is pumped away.

Why is it safer?

If a crack appears in a tanked wall, the system fails and the room floods. With a membrane, the water is simply managed away safely. It doesn't matter if the wall leaks behind the plastic—the room stays dry.

Perimeter drainage channels collect water and direct it to the sump

System Components in Suffolk, Norfolk & Essex

1. The Membrane

Tough, studded plastic sheets (8mm stud typical) are fixed to the walls and floor with specialist sealing plugs. They create an air gap that allows the wall to breathe while keeping the room dry.

2. Drainage Channel

A patented drainage conduit (Waterguard) is installed in a rebate at the floor-wall junction. This captures water coming down the walls and directs it to the sump.

3. Sump Pump

A chamber containing two pumps (Primary + Backup) and a battery backup system. This automatically lifts the collected water to an external drain.

Finishing Your Room in Suffolk, Norfolk & Essex

One of the huge benefits of a membrane system is that it can be dry-lined immediately. There is no drying out time required for the walls.

Walls: Can be battened and boarded, or independent metal stud walls can be built in front.
Floors: Screed can be poured directly over the floor membrane, or a floating timber floor can be laid.
Insulation: Insulation can be easily incorporated into the stud work, making the room warm and energy efficient.

Maintenance

Because the system relies on mechanical pumps and drainage channels, it must be maintained.

Annual pump service required
Jetting of drainage channels to remove silt
Testing of high level alarms

Our Service

We offer maintenance plans from £15/month

Dry, Warm & Safe in Suffolk, Norfolk & Essex

The ultimate protection for your basement conversion.

Ideal for Conversions
Long-term Reliability
BS 8102 Compliant

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Membrane Systems

Checking a Cavity Drainage Membrane System

What signs may indicate a drainage or pump issue behind a membrane?

Unusual water at floor level, a pump alarm, a pump that runs repeatedly, or new dampness around a channel can be reasons to check the system. These signs can have other causes, so do not remove or puncture the membrane to investigate. Note when symptoms began and check any accessible pump controls safely; have the complete drainage arrangement assessed before changing or blocking its outlets.

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