How to deliver on flat roof refurbishment projects


Clients are constantly trying to make the smartest investment, presenting surveyors with the challenge of delivering predictable project costs and providing precise technical data to enable clients to make the correct decision. Bauder explores how to deliver cost certainty and client savings on flat roof refurbishment projects.

With building owners looking to make the smartest investment when maintaining or upgrading buildings, surveyors are required to deliver robust solutions, predictable project costs and precise supporting technical data.

Obtaining this information can often be challenging, especially when trying to detect the extent of any roof issues through a visual assessment. Utilising a variety of differing diagnostic methods however can generate specific data on a roof’s actual condition, creating a comprehensive survey report and specification for the end client.

A moisture mapping survey scientifically verifies the specific levels and locations of moisture within any existing waterproofing system. From this testing method the true condition of the roof is identified, plotted, and a visual data report produced that determines the remedial action needed. This appraisal is an exact scientific survey which provides explicit data on the roof’s actual condition.

Cost Certainty

Using a moisture mapping survey report, a surveyor is able to provide clients with the data gained, proving the extent of the works required and proposals for waterproofing options with correct costings. In this way, the client is assured that they are making investment decisions based on fact rather than on subjective opinions.

Recent roof surveys carried out on three separate but identical 600m² buildings revealed different conditions within the aged waterproofing systems. Moisture mapping was carried out on each of the roofs and a full cost saving analysis provided the client with the following costings for the refurbishments. The savings outlined below were presented to the client who appreciated the proven works required compared to initial recommendations by others for full replacement of all roofs.

In addition to these savings, carrying out an overlay with insulation upgrade or partial strip with overlay will result in a shorter project time. This will in turn reduce associated project costs such as:

  • Shorter contract periods
  • Scaffolding & welfare hire
  • Equipment hire
  • Labour costs

Case study

At Woolwich Polytechnic, for example, a moisture mapping survey report was commissioned to three roof areas within the main roof with a total area of 500m². Using a Troxler 3216 Roof Reader, project surveyors were able to measure the moisture concentration within the roof structure to determine the source and extent of the water ingress.

The moisture mapping report concluded that the existing single ply insulated waterproofing system contained water to several areas with the addition of some localised small areas of water within the existing original build-up. This was estimated to be in the region of 30-40 per cent on the first roof section and 25-35 per cent on the second. The third section of roof contained water to one localised area.

After completing the roof survey, recommendations were made that only the upper roof system required stripping, and with some minimal repair the original roof could be left in situ and overlaid in the usual manor with an upgrade of insulation to comply with the current Part ‘L’ building regulations.

Using the moisture mapping gave the client an exact scientific brief on the roof which led to peace of mind and substantial costs savings on the project.

Bauder is an international manufacturer of building construction materials.