Moisture Control in Internal Walls of Historic Buildings

Controlling moisture in the internal walls of historic buildings is crucial to preserve their structural integrity, aesthetic appeal, and occupant health. Excessive moisture can lead to various problems, including:

  • Rot
  • Mold growth
  • Salt damage
  • Erosion
  • Efflorescence

What should moisture readings be for internal walls?

As a general guideline, moisture readings for internal walls in historic buildings should be below the following:

| Material | Moisture Content (%) |
| —– | —– |
| Brick | 5-8 |
| Stone | 5-10 |
| Render | 5-10 |
| Timber | 12-15 |

These values can vary depending on the specific material, age, and environmental conditions of the building. However, monitoring moisture levels regularly and addressing any excessive moisture promptly is essential to prevent damage.

Causes of Moisture in Internal Walls

Moisture can enter internal walls through various sources, including:

  • Rising damp from the ground
  • Rainwater penetration
  • Condensation
  • Damp external walls
  • Water leaks

Preventive Measures for Moisture Control

Several preventive measures can be implemented to reduce moisture ingress and maintain appropriate moisture levels in internal walls:

  • Install damp-proof courses (DPCs) to prevent rising damp from the ground.
  • Ensure proper rainwater drainage and guttering systems to prevent water ingress.
  • Control condensation by providing ventilation and controlling indoor humidity levels.
  • Regularly inspect and seal external walls to prevent water penetration.
  • Address water leaks promptly to prevent further moisture accumulation.

Monitoring and Repair Techniques

Regular monitoring of moisture levels using moisture meters is crucial to detect and address moisture problems early on. Repair techniques for controlling moisture in internal walls include:

  • Inserting ventilation grilles
  • Installing extraction vents
  • Applying chemical damp-proof courses
  • Underpinning to prevent rising damp
  • Re-rendering external walls
  • Installing dehumidifiers

By adhering to these guidelines and implementing appropriate preventive measures, moisture control in the internal walls of historic buildings can be effectively achieved, preserving their longevity and safeguarding their historical significance.