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Flat roof, Vilvoorde
Damp in the kitchen below a flat roof: the roofing defects located
House
Flat roof
Hygrometry
Fluorescent dye
RESULT
The flat roof defects located, and a second lead identified.
Location
Vilvoorde
Building type
House, rear kitchen
Problem
Damp walls below a flat roof
Methods
Hygrometry, thermal imaging, dye
Conclusion
Probable source
The problem
Several areas of the house were damp, especially the rear kitchen: peeling paint and affected party walls. Directly above the kitchen is a flat roof.
Our intervention
1. Visual inspection of the kitchen and then the flat roof: lifting and broken roofing, a crack around a ventilation penetration, a pipe penetration that was not airtight, and failing perimeter joints.
2. Moisture mapping: on the right-hand wall, 75 at the bottom, 49 in the middle, 28 at the top; on the left-hand wall, 66 at the upper rear.
3. Thermal imaging, combined with spraying the flat roof with hot water: several cold areas on the affected walls.
4. Fluorescent dye on the vulnerable points: nothing appeared during the check. As dye can take several days to migrate, a follow-up check was planned.
Damp in the kitchen: the result of the diagnosis
The sealing defects of the flat roof are a probable source of part of the damage. The very high moisture at the bottom of the right-hand wall also points to a second lead: the neighbouring property or the inspection chamber that backs onto this wall.
Instead of redoing the whole flat roof in the hope of solving the problem, the client knows which defects to repair first, and where to look next.
Our recommendations
• Repair the defects found on the flat roof: roofing, joints, crack and openings.
• Watch for any dye appearing in the kitchen.
• Arrange access to the neighbouring property to check the other side of the wall.
• Have the flat roof repaired by a roofer according to the good practice published by Buildwise.
