During a dampness inspection using a Flir Infrared thermal imaging camera and an MR77 damp meter. I found a long-term issue caused by an incorrectly installed insulation quilt in the roof void. This demonstrates the relationship between dampness and insulation.
The property is a modern tenement building, circa 2000. Its pitched roof uses timber trusses lined with felt.
The front faces West, with the prevailing Southeast wind and continuous eve ventilation. This affects the insulation and contributes to dampness.
Condensation affects the property during wet/cold, and windy weather when the dew point is reached. In this case, the cold sections were 4-5 °C above the dew point temperature.
Cold air from the eave vents can be redirected into the gap between the insulation quilts. This pathway (highlighted in red) allows cold air to travel from the front of the structure to the rear. During stormy conditions, this effect becomes even more pronounced. Additionally, there are sections where the insulation is completely missing. Dampness and insulation issues are becoming common due to inadequate construction supervision and a lack of attention to detail.
Addressing these issues promptly is essential to improving energy efficiency and comfort in the building. If you have any other concerns or need further assistance, please contact me.
This form of dampness is caused by incorrect insulation installation. Due to workmanship issues, we are seeing this more in the UK.
Further reading:
Spray-on roof space insulation has issues. I suggest you read the PCA guidance document, which is available for download at https://www.property-care.org/professionals/sprayed-foam-insulation/
