From TOR to PTM: the trade's guidelines and quality assurance

Every trade has its reference work—the place where doubt is settled. For roofers, it was for decades the TOR guidelines, published by Tagpapbranchens Oplysningsråd, colloquially TOR. Since 1981, the guidelines collected the trade's knowledge about material requirements, construction assemblies, and practical experience with roofing felt and roofing membrane, and they were referenced in bid documents, projects, and disputes throughout the country.

§What was in the TOR directives?

The guidelines covered the entire chain from material to finished roof: requirements for membrane properties, rules for fastening roof covering and roof insulation, recommendations on gradient and drainage — including the well-known recommendation for 1:40 gradient on new roofs — and detail solutions for hip junctions, penetrations and connections. For the designer they were a reference list; for the roofer they were backing for having performed the work according to good practice.

§Competition case

In 2017 the Competition Council ruled that the TOR cooperation and the TOR Approved scheme unlawfully kept new producers out of the roofing felt market and the guidelines were withdrawn. The parties appealed and in 2018 the Competition Appeals Board revoked the decision and sent the case back for reconsideration. In April 2020 the Competition and Consumer Authority closed the case — TOR and the parties behind the cooperation were thus cleared of the charges. But by then the damage was done: the TOR guidelines were gone and according to the industry they will not return in their old form.

§The PTM instructions and other sources today

The need for clear instructions did not disappear with TOR. Phønix Tag Materialer chose to continue the material in the so-called PTM instructions, which are continuously updated and cover topics such as fire requirements, moisture, renovation of low-slope roofs and the execution of green roofs. Other manufacturers issue similar system and installation instructions. In addition, there are BUILD instructions (formerly SBi) on roofs and moisture, as well as building regulations guidance. The difference from the TOR era is that instructions are now manufacturer-specific — so it has become more important to stick to the system you actually use and document which instruction you followed.

§Quality assurance in everyday life

• 01Look up the detail before you improvise — the instructions typically have a solution for your specific situation.
• 02Note in quality assurance which instruction and version you have worked according to.
• 03Photo document hidden details before they are closed: underlining at penetrations connection at roof drains edges.
• 04Record deviations in writing, and obtain the construction manager's approval if the project deviates from the instruction.
• 05Save delivery notes — they prove that the materials installed match the described system solution.

The point of it all is simple: A roof must be able to be defended — not just against rain, but also in a delivery, an arbitration case or an insurance case ten years later. The roofer who can point to the instruction, the photo and the packing slip stands strong. The one who can only say that's how we usually do it stands weak. Quality assurance is not paperwork for paperwork's sake — it is the trade's memory.