Building on gut feeling

Mr Reisinger, you have been with ISOCELL's field service for 25 years. As well as being a renowned expert in building physics and a regular guest on standardisation committees, you are also well known for providing innovative solutions that don't always agree with the textbooks. How did all this come about?

I have always been a man of practice. When I built my house 20 years ago, I had a wooden skeleton construction built by an ISOCELL customer. I did the rest myself, as you learn the most that way. At that time, I had little understanding of building physics — wherever there was a cavity, I blew it full with ISOCELL. Through discussions with experts, such as architects and carpenters, I came to realise that there are generally accepted engineering rules, i.e. standards that cannot be easily ignored, since compliance with them is decisive when determining liability in the case of disputes. However, today I can safely say that I have managed many building projects, which by no means corresponded to the standards — and are still functioning perfectly to this day. The simple reason for this is that our blow-in insulation material can do much more than was previously generally known. Then, around 2002, a new rule for sub-roofs was published, which I simply could not comprehend from a technical viewpoint. So, I applied to Austrian Standards and asked to join the working group that came up with this rule. My application was successful and I'm still active in this working group today.

One of their passions is sealing, a topic that has long been neglected. Why? 
There was no reason for us to raise the issue, because 30 or 40 years ago there were hardly any building defects. Then the level of prosperity increased, and the demand for comfort along with it. Who in the past would have been able to afford to heat all rooms, and to 24 °C? So, the windows had to be sealed, otherwise there is a draught. The thickness of insulation increased along with energy prices and environmental awareness. At the same time, the number of defects increased. At the beginning, the main reason was insufficient sealing of the building envelope itself. I have been part of this development from the very beginning. These days, many people realise how important sealing is. I now spend a third to a quarter of my time clarifying planning details and yes, unfortunately also dealing with defects. These problems affect both lightweight and masonry constructions — and the advice of many self-appointed experts ensures that this keeps happening more and more often. It ultimately doesn't matter which type of construction is chosen. Unless you think properly about the planning and work to a concept, there will be nasty surprises — at the earliest during the blower door test, and at the latest when the people move in. Before the cause of the defect is identified, few people are aware that problems with sound transmission, excessive heat input, drafts, heat loss, and even cold floors are often due to a lack of proper sealing. High-quality, well-engineered sealing is a cost factor, but it pays off. Unfortunately, people often invest in other areas that are far less important. 

You can read the whole article in “THE ISOCELLER 03"