Monitoring fire and flood damaged buildings

Moisture trapped in concrete floors due to a failure in building services, plumbing, under floor heating, firefighting or by flooding can have disastrous consequences if not appropriately dealt with. Below are 2 successful case studies.

Case study 1

A serious plumbing leak in a building in Guernsey led to extensive water penetration to the concrete floors. The insurance company was notified and it was recommended by another company to remove the screed and under floor heating system, to subject the slab to enforced drying.

This option may have solved the problem but it was destructive, extremely expensive and, if carried out, would cause a considerable environmental impact. It would also be necessary for the homeowner to move out of the premises while the works were undertaken, resulting in a major upheaval for everyone.

After considering the costs involved, I was appointed by the Loss Adjuster’s/Insurers to give a second opinion and to carry out an independent non-destructive inspection.

I used state of the art technologies, including thermal imaging, tracer dyes, endoscopy and a range of moisture meters, to determine the extent of moisture damage and to map moisture profiles. This was combined with an understanding of the building construction, materials, structure and pathology of the building. I also checked the floor voids, ambient air, wall voids for levels of mould and took samples from the under floor insulation material, to determine the level and type of mould contamination due to chronic moisture ingress.

Based on my observations and careful analysis of the results of our inspection and monitoring, we recommended leaving the floor screed in situ and over a period of time, monitor the moisture and mould infestation levels.

Our further monitoring and testing revealed that the moisture and mould levels had reduced to acceptable levels and this negated the need to remove the floor screed and under floor heating.

This is an excellent example of why you should only employ an independent consultant who has a proven track record of solving tricky building problems, and as a result avoid destructive, extremely inconvenient and exceptionally expensive measures.

Case study 2

I was requested by Loss Adjuster’s/Insurers to give independent advice on the extent of damage and propose a drying regime for a building that had been damaged by a plumbing failure. The new build, three-storey block of apartments had almost been completed when the flooding occurred. Approximately 100,000 litres of water were released.

Initially it was thought that water had not saturated the concrete floor beneath the under floor heating screed membrane but after a thorough examination, it was found that the slab was saturated and it would therefore be essential to dry out the concrete.

Unfortunately it could not be dried properly with the screed in place, as the moisture was trapped under the damp proof membrane and a galvanised metal deck under the concrete slab. There was a risk that any trapped moisture would gradually evaporate at the perimeters of the rooms and damage the high quality wall finishes.

Unlike case study 1, the moisture was trapped and there was unfortunately no alternative but to remove the screed and under floor heating to expose the slab. Infra-red heaters and fans were then used to dry out the exposed concrete slab. The moisture mapping and drying out was monitored using a range of non-destructive technologies including VAISALA plugs and humidity measurements.

As a direct result of our input, an anticipated drying time of 3 months was achieved in only 2 months, resulting in a considerable time and cost saving to our client.

Figure 1: Moisture monitoring in a concrete floor