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Glossary term

Relative humidity

Moisture in air expressed relative to the maximum the air can hold at the same temperature.

Updated 2026-08-30

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Sources and evidence

Method & sources →

Source types stay separate: technical and authority-adjacent sources support rules and risk topics, while project sources document practical experience.

2 technical/authority sourcesUpdated 2026-08-30

Technical checkpoints

1dew point and surface temperature
2actual air-change path
3intended use of the room
4changes after rain
5warm/humid summer weather
6condition of the substrate

Relevant guides

Monitoring basement humidity

Monitoring basement humidity. Start by documenting dew point and surface temperature, actual air-change path and intended use of the room. The purpose is to understand the building condition and constraints before choosing products, finishes or a work sequence.

Humidity-controlled basement ventilation

Humidity-controlled basement ventilation. Check actual air-change path, dew point and surface temperature and intended use of the room before deciding what to repair. These observations help separate a surface symptom from water, air, drainage or construction conditions.

Problem scenarios

Basement still damp after new drainageBasement floor wet but walls dryBasement humidity is high only in summerVentilation makes the basement wetter in summer

Relevant real cases

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Continue in the same topic

Related guides, problems, checklists, cases and technical terms from the same knowledge area.

GuideBasement condensation in summer: when opening windows adds moisture→GuideHumidity-controlled basement ventilation→GuideMonitoring basement humidity→ScenarioBasement humidity is high only in summer→ScenarioVentilation makes the basement wetter in summer→ProblemCondensation / summer damp→ProblemCracks or movement→ProblemDamp or wet wall→ScenarioBasement feels damp and cold but humidity readings look normal→ChecklistBasement ventilation installation checklist→

Evidence & moderation

Editorial policy →
WHO guidelines for indoor air quality: dampness and mouldWorld Health Organization↗WHO handbook on indoor radon: a public health perspectiveWorld Health Organization↗
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