Completing a Building Moisture Inspection: A Step-by-Step Guide

Moisture issues in buildings are like silent intruders, often going unnoticed until the damage becomes extensive. 

Whether it's structural harm, mold, or even health concerns, ignoring the early signs can lead to costly repairs and unsafe living conditions. 

The good news? 

Detecting these issues early on with the right tools and techniques can save you from these headaches.

Let’s walk through how to perform a building moisture inspection, drawing on expertise from professionals and tools like the Protimeter SurveyMaster and HygroMaster. We'll also provide practical insights for detecting common issues such as condensation, rising damp, and salt contamination.

Introducing the New SurveyMaster

Diagnosing Moisture in Buildings: Where to Start?

Different building types, from old brick homes to modern constructions, have different vulnerabilities to moisture-related problems. When beginning your moisture inspection, it’s important to consider: 

• The age of the building 
• Its construction materials
• Any reported issues from the occupants

For example (as seen in the video that goes with this article), a 1930s cavity wall construction with solid floors might have a damp proof course (DPC) designed to prevent rising damp. However, issues like rainwater ingress, condensation, or a bridged damp proof course could still cause dampness. A moisture inspection requires careful examination to identify the root cause.

Identifying Common Moisture Issues

When conducting a moisture inspection, there are three primary moisture issues to investigate:

• Condensation: This issue can easily go unnoticed due to poor ventilation -– until significant damage occurs. High humidity levels are a common cause of condensation. You can identify this problem by analyzing windows, walls, and corners — common areas where condensation accumulates.
• Rising Damp: Occurs when groundwater travels up through a building’s walls due to the failure or absence of a damp proof course. You can detect this using specialized tools to test for nitrates and chlorides, which are signs of rising damp. Left untreated, rising damp can cause damage to plaster, masonry, and decoration.
• Bridged Damp Proof Course: Arises when external ground levels are higher than the internal flooring, allowing moisture to bypass the course. It often occurs in older buildings, especially when external renovations elevate the ground level. Inspectors should carefully examine the building’s external perimeter to spot this issue early.
  
  

Resource: Want to know more about measuring condensation in buildings? Download our guide:

Using Moisture Meters for Initial Diagnosis

Tools like the Protimeter SurveyMaster help you thoroughly inspect moisture issues. When beginning the inspection, run the moisture meter along suspected problem areas, like at the base of walls or near window sills. The meter’s readings can help narrow down areas of concern. High readings at the base of a wall, for example, may indicate rising damp or salt contamination.

Professional Surveying Equipment

Accurate moisture detection hinges on the use of reliable tools. Two devices you’ll want on hand are:

Pin Mode vs. Non-Invasive Mode

The SurveyMaster’s pin mode is useful for checking timber skirting boards or areas where precise readings are a must. The non-invasive mode, on the other hand, allows broader surface scans. 

Both modes offer vital insights. For example, high readings at the base of a wall that taper off as you move upward suggest a rising damp issue, often caused by a bridged damp proof course.

Investigating Rising Damp: A Case Study

In many older buildings, rising damp occurs when moisture from the ground moves upward through porous materials like brick or plaster. This is often exacerbated by a bridged DPC, where solid floors or other materials bypass the dampproof barrier.

In the building in the video (see above), a bridged slate DPC was causing rising damp at the base of the walls. High moisture readings led the inspector to remove a section of plaster, revealing the slate DPC being compromised by the solid floor construction. This allowed moisture to rise into the wall, depositing salts like nitrates and chlorides in the plaster. These salts, being conductive, can lead to falsely high moisture readings.

Salt Contamination: Nitrates and Chlorides

Nitrates and chlorides are two common salts that can accumulate in damp plaster. These salts are hygroscopic, meaning they can attract moisture from the air, making the wall appear damp even If you eliminate the initial source. Without advanced tools, it’s nearly impossible to identify and treat this issue effectively.

To confirm salt contamination, also known as efflorescence, you can perform a simple nitrate and chloride test. In the case study building (see above), a sample of plaster was taken, and the nitrate test returned a red result, indicating significant contamination. Similarly, the chloride test turned yellow, confirming the presence of chlorides. These results, combined with the moisture meter readings, helped confirm the diagnosis of rising damp due to a bridged DPC.

Resource: Learn how Protimeter Moisture Meters can help you measure damp in buildings

Condensation Problems and the Importance of Dew Point

Condensation is common in colder weather. Condensation forms when warm, humid air comes into contact with cold surfaces, causing moisture to settle on walls, windows, or ceilings. The key to diagnosing condensation is determining whether the wall or surface is below the dew point, the temperature at which moisture in the air condenses into liquid.

Inspectors use a hygrometer to measure air temperature, humidity, surface temperature, and dew point to determine if condensation is occurring. In the video above, the HygroMaster showed the wall temperature to be 41°F (5°C) above the dew point, ruling out condensation as the instigator.

Moisture Inspections Under Floor Coverings

Moisture problems aren’t limited to walls. Floors, especially those with solid construction, can also suffer from moisture ingress. Inspecting under carpets, vinyl flooring, and other coverings is essential when moisture issues are suspected in the floor structure.

The Protimeter SurveyMaster can be used in pin mode through carpets to get accurate readings without lifting the floor covering. In non-invasive mode, it can scan through materials like vinyl to detect hidden moisture. In the video above, high readings under a vinyl floor led the inspector to pull back the covering, revealing rust marks and staining caused by moisture in the solid floor.

Moisture Inspection: A Process of Elimination

Building moisture inspections are rarely straightforward. They require a careful approach, combining professional tools with expertise in building construction and moisture behavior. 

By following a systematic process of elimination — ruling out condensation with dew point measurements, testing for salts, and investigating moisture ingress with meters — you can confidently diagnose the moisture issues in any building. Accurate diagnosis is the first step in effective remediation, ensuring that moisture problems are addressed before they cause lasting damage or impact occupants' health.

Add a Protimeter Product to Your Toolkit

Find the Protimeter moisture meter and other inspection tools that are right for your job site: