The pioneers. Flat roof accessories since 1962.

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Marrying innovation with craftsmanship and ingenuity, all the while remaining faithful to our traditional roots: b/s/t creates intelligent, made-to-measure product solutions for flat roofs. Simplicity is key: our business, processes and products are based on clarity, experience, reliability and quality.

The management
Hans-Jürgen Koch (†) with his two sons Sebastian and Johannes Koch

b/s/t. The pioneers. Flat roof accessories since 1962.

The management: An interview with Hans-Jürgen Koch (†), Johannes and Sebastian Koch

What made you want to manufacture products for flat roofs?

Hans-Jürgen Koch (†): In the 1920s, my grandfather made paints, seals and mastics from tar and bitumen. My father set up the business at Rimsting am Chiemsee in 1948. In 1952 we were the first to have the idea of replacing a bitumen roof with PVC roofing strips. We started by testing the seals on railway cars and under various climate conditions; after about 10 years, we found we needed to design accessories for a functioning flat roof too. Our products were simple, technically sound and were proven to work. The foundations of b/s/t were laid.

In the 1950s, flat roofs were all the rage ...

Johannes Koch: That's right, flat roofs expressed an avant-garde architectural language of forms. When it came to making accessories for flat roofs, my grandfather was a real pioneer.

Do you feel like you're pioneers too?

Johannes Koch: We've always been pioneers – innovation runs in our family. Our great-grandfather originally designed cars. Our grandfather revolutionised the flat roof seal. As well as developing b/s/t further, our father shaped the textile architecture branch with our sister company Koch Membranen GmbH Kunststofftechnologie. As his sons, our role is to now ensure that this family history continues over the years and generations to come.

What is it exactly that accessories do in a building?

Hans-Jürgen Koch (†): Our products may look plain and have little impact on design in most cases, but they are extremely important in terms of their function - that is, solving the critical issues in flat roof sealing. While accessories are only a small part of a building, the consequences for the whole building can be disastrous if they go wrong. Which is why quality is always paramount as far as we're concerned.

What does the future hold for b/s/t?

Sebastian Koch: The characteristic features of our quality will remain: simple, flexible, individualised, hand-made, high-quality products in tandem with a reliable service in which we strive to meet tight deadlines and strenghn our regional networks. Moreover, we will be integrating the benefits presented by the younger generation: new ways of communicating, cutting-edge technology, optimised procedures and perhaps even the latest innovative product development soon.

Recognising necessities.

Sales:  An interview with Markus Mayer

What can b/s/t's customers expect from you?

Markus Mayer: We offer our customers a comprehensive range of accessories for their specific flat roof. Every product is customised. Our clients are based in 24 countries across Europe. We work with local sales partners who speak the relevant language and are conscious of the specific needs of that country.

How does your 24-hour service work?

Markus Mayer: We manufacture the majority of our products in line with the specific requirements of each respective project here in-house. When required and providing it is technically feasible, we deliver within 24 hours. We know that timing can be very critical on construction sites at times. With this in mind, we do our utmost to tailor our production to meet our customers' requirements.

Service means …

… offering customers exactly what they need – not necessarily always what they want. It’s our job to ascertain the subtle difference between these two things. It’s an important step in guaranteeing quality.


Markus Mayer
Michael Zimmermann

Simple but functional.

Technology:  An interview with Michael Zimmermann

What's so special about your products?

Michael Zimmermann: Most of our products come about as a result of practical use and are simple but functional. Each fitted part comes with a connecting sleeve, so our customers can work faster and more surely. We're known in the industry for special solutions when it comes to working with plastics. Even our competitors recommend us.

What are your customers’ technical requirements?

Michael Zimmermann: We help them with all their flat roof design work by providing technical support with guidelines for use and standards, calculations for draining flat roofs or holding roof seals safely in place. Dimensioning drainage is an art in itself; getting the results wrong can be dangerous. That's where our expert knowledge really comes in to play.

How would you describe your production processes?

Michael Zimmermann: We manufacture the majority of our products, above all the plastic components, here in-house. Semi-finished materials are combined to create a completed product. Most are hand-made by specialists. Our team is highly versatile and experienced.

Quality through simple functionality: b/s/t offers a full range of flat roof accessories, competent professional consultancy and design support. We work in 24 countries, tailoring everything to suit our customers’ needs for customised or special products. b/s/t stands for simple, tailor-made solutions, lasting quality and reliable service. Your projects provide our motivation.
We take semi-finished materials and combine them to create a customised product.
The specialists who together form our manufacturing team are above all distinguished by their ability to closely collaborate with each other.
We use specialist processing machines, we're highly quality-conscious and we put in place stringent quality control measures in order to guarantee the high standards we place on our products.