Defects - Damp Flashcards
What are the potential causes of internal damp?
Condensation
Rising Damp
Penetrating Damp
Cold Bridge
How would you mitigate condensation?
Review the activites within the room that are generating moisture, improve the ventilation and improve the heating and insulation.
What is penetrating damp?
Penetrating damp occurs where moisture enters a building through a porous bridge. This could be from single skin masonry, water trapped behind a render, mortar on cavity wall ties or where an external defect allows moisture to track in.
What are the remedies for penetrating damp?
Repointing masonry, making good external defects, inspection of the cavity trays and cavity wall ties to ensure they are clear of debris and inspect the roof.
What is rising damp?
Rising damp occurs where water transfers through capillary action from the ground up through the masonry. This usually indicates a defective or missing DPC, or where the DPC is bridged by an adjoining element.
How would you remediate rising damp?
Rising damp may be remediated by reinstating the DPC to the affected area and removing any adjoining element that may be bridging the DPC.
What is a cold bridge?
A cold bridge occurs where two materials that are poor thermal insulators come into contact and allow heat to move through. This usually creates a spot where moisture is more likely to condense.
How do you remedy a cold bridge?
The bridge must be eliminated, and replaced with materials with better insulating properties.
What is the difference between surface and interstitial condensation?
Surface condensation occurs where warm, moist air comes into contact with a cooler surface and condenses.
Interstitial condensation occurs where warm, moist air permeates through elements of a building’s fabric across which there is a temperature difference, meaning that it can more suddenly reach it’s ‘dew point’ temperature.
