Insulated DPC

Insulated DPC combines a damp-proof course with a thermal break in a single component. Specified at the wall-base junction, it stops both moisture ingress and the cold bridging that occurs where the inner leaf bears directly onto the foundation — better thermal performance at the slab edge, and a lower risk of condensation and mould at skirting level.

The Insulated DPC Range We Stock

IKO Hyload Insulated DPC — flexible rolls

The roll format lays into the mortar bed like a conventional DPC, with a bonded insulation strip on the inner face. Stocked widths:

ARC Rockfibre Insulated DPC — rigid, Euroclass A1

Rigid 1200mm lengths with a Euroclass A1 rock-fibre core and an embossed polyethylene DPC layer — the non-combustible option where fire performance at the junction matters. Available in gap sizes from 15mm to 65mm in 5mm steps, in two profiles: 100/165mm (100mm block face) and 140/225mm (140mm block face). Browse the full range: ARC Rockfibre Insulated DPC.

Which Size Do I Need?

Inner leafDPC widthFlexible rollRigid A1 (by gap size)
100mm block165mmHyload 165mmRockfibre RFDPC165 (15–65mm gap)
140mm block225mmHyload 225mmRockfibre RFDPC225 (15–65mm gap)

For Rockfibre, the gap size is the insulation thickness — match it to the gap you are closing and allow the recommended compression fit (the A1 core delivers its fire integrity when compressed by around 15mm on installation, per ARC's guidance).

Roll or Rigid?

Choose the Hyload roll for standard coursework: it handles like conventional DPC, follows the bed joint, and suits long continuous runs. Choose ARC Rockfibre where the specification calls for non-combustible materials or a fire-rated junction detail — party walls, reveals and relevant buildings under Approved Document B — or where a rigid board suits the detail better than a roll.

Where It's Specified

Wall-base junctions on new build, the slab edge on beam-and-block floors, party wall junctions, and thresholds where the DPC line crosses a heated-to-unheated boundary. In each case the insulated DPC replaces the plain DPC in that course — it is not an addition to it.

Insulated DPC: Common Questions

What is insulated DPC?

A damp-proof course with insulation bonded to it, installed in the mortar bed where a plain DPC would sit. It blocks rising moisture and breaks the cold bridge at the wall base in one component.

What widths does insulated DPC come in?

165mm for 100mm inner leaves and 225mm for 140mm blockwork are the stocked widths, in flexible rolls (8m and 10m) or rigid 1200mm lengths.

Is there a non-combustible insulated DPC?

Yes — ARC Rockfibre uses a Euroclass A1 rock-fibre core with an embossed polyethylene DPC layer, stocked in gap sizes from 15mm to 65mm.

Which brands do you stock?

IKO Hyload for flexible rolls and ARC Rockfibre for rigid A1 lengths. For plain (non-insulated) DPC see our damp-proof course range, including Hyload Original and Damex FR non-combustible DPC.

Not sure which option fits your detail? Our insulated DPC selection guide works through the decision step by step.

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