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Rising Damp

Understanding the Risk in Your Future Home

Rising damp is a moisture issue that affects masonry walls by drawing ground water up through the structure. It’s most common in older buildings, where the original damp-proof course (DPC) has failed, but it can also appear in homes with poor drainage or subfloor ventilation. At True Inspect, we identify and report rising damp as part of our pre-purchase inspections, so buyers know exactly what they’re dealing with — and how serious it is.

What Is Rising Damp?

Rising damp occurs when water from the ground travels up through porous materials like bricks or mortar by capillary action — like a sponge soaking up water. Normally, a damp-proof course prevents this upward movement. But if it’s missing, damaged, or bridged by soil or paving, moisture can seep into internal walls.

Unlike other moisture types (e.g. rain or condensation), rising damp moves vertically from the ground, often stopping at 1 to 1.5 metres. It also carries salts from the soil, which can worsen wall damage over time.

Key Causes of Rising Damp

Our inspections often uncover rising damp caused by:

  • Damaged or aged damp-proof courses
  • Bridging of the DPC by soil, garden beds, render, or raised paving
  • High ground levels or inadequate drainage
  • Blocked or insufficient subfloor ventilation
  • Plumbing leaks saturating surrounding soil
  • Poorly executed renovations or additions

Each inspection includes a review of ground levels, ventilation, visible DPC lines, and any factors that may be contributing to rising damp.

What We Look For

Rising damp leaves some classic signs that our inspectors know to identify. These include:

  • Tide marks on interior walls (a visible horizontal stain or salt band)
  • Efflorescence, or white salt deposits on bricks or plaster
  • Peeling paint, blistering wallpaper, or flaking skirting boards
  • Musty odours or mould at the base of walls
  • Soft or crumbling timber, especially in skirting or floorboards
  • Elevated moisture readings with a sharp gradient near the floor

Our team uses non-invasive moisture meters and thorough visual checks to confirm and document the extent of damp and its likely source.

Why Rising Damp Matters

Rising damp is more than cosmetic. Left unchecked, it can lead to:

  • Plaster deterioration and bubbling or flaking surfaces
  • Brick fretting or mortar erosion in severe cases
  • Rot in wall plates or floor timbers, compromising structural integrity
  • Mould and poor air quality, especially dangerous for those with allergies or asthma
  • Increased termite risk, as moist timber attracts pests
  • Reduced property value or complications in resale and negotiations

Buyers should be especially cautious when damp is widespread, active, or linked to structural decay.

How We Report It

True Inspect follows AS 4349.1 (Australian Standard for Pre-Purchase Building Inspections) when identifying and classifying rising damp. If detected, your report will include:

  • Photos and descriptions of affected areas
  • Moisture meter readings showing damp concentration
  • Assessment of likely causes (e.g. DPC failure, bridging, drainage issues)
  • Recommendations for further assessment or repair (e.g. by a builder or damp specialist)

We also explain what’s urgent, what’s manageable, and what to monitor. Where needed, we note termite implications or health risks related to the damp.

What You Should Do

If rising damp is found in your inspection:

  • Don’t panic — many cases are manageable if caught early
  • Request quotes for repairs and assess severity
  • Understand the source — a temporary cosmetic fix won’t solve the problem
  • Ask about potential timber pest implications if moisture is near flooring
  • Negotiate with the seller based on findings, or factor in repair costs

Remedies may include lowering external ground levels, fixing drainage, or installing a new DPC (e.g. chemical injection). If the area is contaminated with hygroscopic salts, plaster replacement may also be required.

For more information, download the full information pack on Rising Damp.

Includes diagrams, examples, causes, remediation methods, inspection tools, and standards references.

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