Bridged damp-proof courses and raised thresholds

Technically reviewed by Savas Bulduk BSc (Hons) MRICS, Director & Chartered Building Surveyor · last reviewed 2026-07-20. General information only — not a survey of a specific property.

What it means

External paths, renders, planters and insulation can bridge a damp-proof course, allowing moisture past the intended barrier. Internal low-level damp then appears even where a DPC exists. Correction is usually external level/render detailing, not injection alone.

What you might notice

External ground or path above DPC line
Render continuous across the DPC
Planters hard against walls
Low-level internal damp opposite bridged zones

How it may be investigated

Locate DPC line and external bridging features
Lower ground or introduce drainage channels as appropriate
Remove bridging render/plaster
Reassess residual salts after bridging removed

Recommended next step

The proportionate instruction depends on the building, the concern and what an inspection can reasonably establish. HCS confirms the scope before you book.

Instruct a building pathology / defect survey

Cause-led diagnosis for a defined damp, leak, crack or fabric problem — not a full purchase survey.

Also consider

Instruct a RICS Level 3 Building Survey — Detailed survey for older, altered, listed, non-standard or defective London property.
Instruct a RICS Level 2 Home Survey — Proportionate mid-level pre-purchase survey for conventional stock in reasonable condition.
Not sure Level 2 or Level 3? Use the survey chooser — Use the live HCS tool for an indicative comparison, then confirm the scope before instruction.

Related HCS services and area guides

Sources and evidence

These references are background sources. They do not establish the cause or condition of a particular property.

Historic England — Damp in Historic Buildings · checked 2026-07-20
Property Care Association — damp and timber guidance (public) · checked 2026-07-20

Ask a surveyor

Not sure what this means for your property? Speak with a Chartered Surveyor atHampstead Chartered Surveyors & Building Consultancy.

General library guidance is not a survey of your building. A short conversation helps confirm the proportionate next step.

Request advice Book inspection Discuss survey findings

From Survey Findings to Remedial Design, Tendering & Execution

Once our RICS chartered building surveyors have diagnosed the root cause of a defect through a Specific Defect & Building Pathology Investigation or RICS Home Survey, you can either instruct Hampstead Chartered Surveyors independently for JCT Contract Administration to tender the works to external contractors, or elect our joined-up group design-and-build route alongside our sister practices:

Hampstead Architecture & Planning: Architectural drawings, conservation-area and listed-building consents, structural engineering coordination, and Building Regulations packages translated directly from the survey diagnostics.
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