On the front line of the Gävle floods, expertise met urgent needs

As a moisture consultant, Johan Öberg is used to investigating problems and working through detailed reports. Helping in the aftermath of the torrential rain in Gävle meant making quick decisions on site, in the homes of people whose lives had been turned upside down. The experience gave him a deeper understanding of his moisture technician colleagues’ work.

In one elderly woman’s home, furniture had been washed away. Internal doors had turned to pulp, and snails were crawling over the paintings. To rescue photo albums and other valuables, Johan and his colleagues had to prise open swollen cupboards.

It was one of the most severe examples of flood damage I have encountered. You could only imagine what it meant for the homeowner to see a lifetime of belongings affected.

Johan was one of the colleagues who travelled to Gävle to support the local moisture technicians after the torrential rain. During the response, he visited around a hundred affected property owners.

It was daunting at first, but I gradually got used to the work.

People’s reactions were harder to get used to. Skips filled with ruined belongings lined the streets. He encountered tears, frustration and people who had lost everything.

Decisions couldn’t wait—and collaboration was key

The work in Gävle was very different from Johan’s usual consultancy assignments. Normally, he can spend hours working on an investigation report before asking a colleague to review it. Here, damage had to be assessed, documentation completed and drying equipment set up while those affected waited for answers.

Feedback came faster, too. Builders and insurance companies got in touch as soon as reports were submitted, and he was in direct contact with property owners.

“I felt truly appreciated, and that I was doing something valuable for the community.”

The experience left Johan keen to encourage other consultants to try working alongside moisture technicians. For him, it provided a clearer picture of the conditions his colleagues work in and the decisions they need to make on site.

When the customer is 100 kilometres away, preparation matters

In his own consultancy role in southern Norrland, Johan faces a different set of challenges. His district stretches from Gävle to Umeå, and he estimates that the average customer is 100 kilometres away—one way.

That makes a return visit costly. Understanding the problem early, talking through the circumstances with the customer and bringing the right equipment from the start are essential.

The assignments also call for curiosity. Johan investigates everything from cold, draughty homes and leaking roofs to odour problems and moisture in historic buildings. One of his more unusual assignments involved a goat farm housed in a tent in the forest, where keeping the animals was causing major moisture problems.

More eyes on the problem, more expertise to draw on

When Johan joined Polygon in October 2020, the consultancy role was new to the local office. The pandemic limited opportunities to connect with others, and his nearest fellow consultant was a long way away. Finding customers and building relationships with the region’s moisture technicians became an important part of getting started.

Over time, that collaboration grew. Today, he describes how moisture technicians and consultants can complement each other’s expertise—for example, when water damage also calls for moisture monitoring or an indoor environment investigation.

Johan calls it getting “more eyes on the problem”. Working together helps colleagues understand each other’s expertise and recognise when to draw on a colleague’s skills to give customers a thorough, high-quality investigation and the best possible support during a challenging time.

From on-site investigations to scientific research

Research in building physics is an integral part of Johan’s consultancy work. His work combines investigation of moisture-related building performance issues with the analysis of long-term measurement data from real buildings, helping to improve and validate methods used in practice. By integrating research activities into Polygon’s consulting projects, he contributes to the development of more reliable approaches for moisture assessment, hygrothermal simulation, and moisture-safe building design.

As lead author of the recently published study Evaluation of Hygrothermal Calculation Models for Ventilated Roofs, co-authored with S. Olof Mundt-Petersen, Johan has contributed to advancing the understanding of heat and moisture transport in ventilated roof structures. The study looks at how well hygrothermal simulation models reflect long-term measurements from Swedish buildings, supporting more reliable moisture risk assessments in practice.

In addition to his research publications, Johan has presented technical work and project experiences at conferences and industry events across Europe and the United States, exchanging insights with others working in building physics, moisture safety and building performance

Read the full study on ScienceDirect.

Want to learn more about Johan’s work or discuss a project? Contact Johan Öberg