Emergency Damp Proofing Guide

A specialist emergency response focuses on identifying the root cause—whether it is penetrating damp from a storm, a breached damp proof course (DPC), or a plumbing failure—and applying immediate remedial measures to stabilise the property. Acting quickly can save thousands in long-term structural repairs and redecoration costs.

What Does the Work Involve?

• Moisture Mapping: Using protimeters and thermal imaging cameras to track the spread of moisture behind walls and under floors.
• Source Identification: Checking for external breaches like cracked rendering, blocked gutters, or high ground levels bridging the DPC.
• Salt Neutralisation: Applying treatments to masonry to prevent hygroscopic salts from drawing more moisture from the air.
• Emergency DPC Injection: Installing a chemical damp proof course to create a new hydrophobic barrier in the mortar line.
• Tanking & Membranes: Applying waterproof slurries or studded membranes to internally "seal" a wall in high-risk areas like basements.
• Industrial Drying: Deploying high-capacity dehumidifiers and air movers to extract deep-seated moisture from the building fabric.

Typical Costs

Prices vary based on the thickness of the walls and the severity of the moisture saturation. Remember that these costs cover the damp proofing itself; subsequent replastering with salt-resistant mortar is often an additional expense.

How Long Does It Take?

• Initial Assessment: 1–2 hours to identify the source and map the affected area.
• Emergency Chemical Injection: 3–6 hours for a standard ground-floor room.
• Tanking or Membrane Installation: 1–2 days depending on the size of the room and wall preparation needed.
• Drying Out Period: 2 weeks to several months. A general rule is one month of drying time for every 25mm of wall thickness.

DIY or Professional?

Damp proofing is rarely a suitable DIY project because misdiagnosis is incredibly common and expensive to fix.

While DIY "damp-proof" paints are available, they often mask the problem, causing moisture to build up behind the paint and blow the plaster off the wall. Professional damp proofers have the diagnostic tools to distinguish between rising damp, penetrating damp, and condensation, ensuring the right treatment is applied the first time.

Choosing the Right Tradesperson

• Check Qualifications: Look for technicians with CSRT (Certificated Surveyor in Remedial Treatments) or CSTDB (Certificated Surveyor in Timber and Dampness in Buildings) credentials.
• PCA Membership: Ensure the firm is a member of the Property Care Association (PCA), which sets the industry standard for damp remediation.
• Insurance-Backed Guarantees (IBG): Always ask if their work comes with a guarantee that remains valid even if the company stops trading.
• Questions to Ask:
  • Is this rising damp or penetrating damp, and how have you proven it?
  • Will you provide a full moisture map of the affected area?
  • Does the quote include the removal and replacement of salt-contaminated plaster?

UK Regulations

• Building Regulations Part C: Covers resistance to contaminants and moisture. Any new DPC or significant structural drying must comply with these standards.
• BS 6576: The British Standard code of practice for the installation of chemical damp proof courses.
• Health and Safety: Contractors must provide COSHH (Control of Substances Hazardous to Health) sheets for any chemicals injected into your walls.

Common Problems

• Bridging the DPC: This occurs when new patios or flower beds are built above the level of the damp proof course, allowing moisture to bypass the barrier.
• Treating the Symptom, Not the Cause: Injecting a DPC when the real issue is a leaking gutter or high external ground levels.
• Inadequate Replastering: Using standard gypsum plaster after a damp treatment instead of a specialist salt-retardant mix, leading to "salt damp" returning within months.
• Poor Ventilation: Blocking air bricks while trying to "seal" a house, which actually traps moisture and accelerates timber rot.

Frequently Asked Questions

Is emergency damp proofing covered by home insurance?

Generally, home insurance covers damp only if it is the result of a "sudden peril" like a burst pipe or storm damage to the roof. It rarely covers rising damp or issues caused by lack of maintenance.

Can I paint over the area immediately after treatment?

No. You must allow the wall to dry completely, which can take weeks. Using a breathable "trade matt" emulsion is often recommended initially, as gloss or vinyl paints will trap moisture and bubble.

What is the difference between rising and penetrating damp?

Rising damp travels upwards from the ground through capillary action in the masonry. Penetrating damp enters horizontally through walls, usually due to structural defects like cracked bricks or failed seals.

Do I need to move out during the work?

Usually not. However, the process can be noisy and dusty, especially if salt-contaminated plaster needs to be hacked off. High-capacity dehumidifiers can also be quite loud.

How do I know if the damp treatment has worked?

A professional should return after a few weeks to re-test the moisture levels with a meter. You should also see a visible reduction in damp patches and a decrease in the "musty" smell.