EFYOS BLUE SMART A: combining roof falls and thermal insulation

A plan of the falls with each wedge marked will be required, since a flat view of the field alone does not show all the heights. When buying EFYOS BLUE SMART A, it is worth agreeing this part first, before the thickness becomes an assumption for the remaining works.

In EFYOS BLUE SMART A the core is made of PIR, with aluminium facings on both sides. The manufacturer states a format of 1200 × 1200 mm, straight edges and a nominal fall of 2.08%. Lambda is 0.022 W/(m·K), the compression level is CS(10)150, and the reaction to fire is class E. Since various elements shaping the roof slope belong to the system, the number of square metres alone does not describe a complete order. PIR SOPREMA boards should be assessed here for the scope that is a flat roof with tapered insulation and point drainage. When checking an order, the term polyurethane boards does not replace the full name EFYOS BLUE SMART A. Polyurethane foam of the PIR type forms the core of EFYOS BLUE SMART A; the properties of the complete board also include its facings.

To illustrate the geometry, let us take a 3.00 m section with a constant slope of 2.08%. The height difference between its ends will be approximately 62.4 mm. In the EFYOS BLUE SMART A family the stated fall value is based on the documentation, but the example does not define the complete field or the starting height. The level at the outlet also depends on the substrate and the base layers. A detail covering the lowest part of the insulation next to the outlet must also be prepared. The result should not be treated as the thermal resistance of the roof. Checking the execution requires a plan of the falls with each wedge marked and the actual course of all sections.

In the example concerning EFYOS BLUE SMART A, the figures describe only the specified part of the task. They are meaningful together with a measurement that includes the outlet level and the end heights of each fall field. The property relevant for comparison is the nominal fall of 2.08%. In this arrangement, the direction in which thickness increases must also be checked before the field is covered. Only then does a fall plan with the individual tapered sections marked allow the result to be related to the actual section. The energy calculation should retain the same scope also when comparing with another thickness of EFYOS BLUE SMART A.

The first direction is to relocate the water collection point. The second is to retain the outlet and change the thickness distribution. The scope of both measures depends on how significant the lowest section of insulation next to the outlet is. In the variant with EFYOS BLUE SMART A, the cost of the entire surface should not be increased before the local constraint has been investigated. A pitfall would be reversing a similar tapered section or omitting the underlying layer, even if the result for the main field looks favourable. The comparison is only complete when the schedule of specific fall elements and their positions also covers the differences caused by changing the variant.

The design should clearly specify the straight board joint in the planned arrangement of tapered sections. In the description of EFYOS BLUE SMART A, it is worth separating its geometry from the tightness of the other layers. The product surface is formed by a blue aluminium facing on the fall element, but its presence does not automatically resolve the entire detail. A schedule of element numbers matching the layout plan is needed for checking. The next stage will be the covering that reproduces the designed falls, so the error should not be passed on to the installer of the next layer. It is worth recording at handover how the lowest section of insulation next to the outlet was executed and why that particular method was chosen.

The quotation for EFYOS BLUE SMART A should relate to the completed task, not to a single favourable parameter. The calculation should include a schedule of specific fall elements and their positions. A separate cost may arise because support is also needed for the thinnest sections at the drain. It is also worth pricing the work on the detail described as the lowest section of insulation next to the outlet. The differences should be explained by the designer of the drainage and tapered insulation, so that the saving does not result from removing a necessary layer. Polyurethane insulation compared in this way corresponds to the actual effect that a flat roof with tapered insulation and point drainage is intended to achieve.

The selection can be regarded as orderly when drainage has been combined with adequate insulation thickness at the drain. For EFYOS BLUE SMART A, this means combining material data with the solution for the perimeter and the other layers. The document to retain is the fall plan with the individual tapered sections marked. It should be accompanied by a schedule of element numbers matching the layout plan, so that later renovation does not begin with guessing the product. There is no need to add a promise of a quick payback without a building balance. If the range of level difference between the outlet and the perimeter changes, it is necessary to return to the comparison instead of copying the previous thickness. Polyurethane insulation has a specific purpose here: to combine drainage with adequate insulation thickness at the drain.