High-Pressure Laminates in Rainscreen Facade

A highly durable solution with design freedom and flexibility
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Sponsored by Trespa North America Ltd.
By Peter J. Arsenault, FAIA, NCARB, LEED AP

Part 1: General

The scope of the specified work can include all preparation, substrate review, product choices, and final installation. In terms of specifying performance, the appropriate ASTM and European (EN) testing standards should be referenced both for the substrate (the exterior wall assembly, including the WRB and continuous insulation) and the HPL products.

Submittals for HPL panels and support systems should include the usual manufacturer’s data and information for all products used, plus samples with color and texture data to confirm the correct appearance is being achieved.

Quality assurance is clearly an important part of any field-installed system, and the same is true here. Installers should have qualifications. Evidence of such qualifications can be requested as a submittal, but it is important that the people actually in the field are the ones with the qualifications and experience needed.

On-site protection of products should be carried out according to the manufacturer’s instructions and recommendations, particularly if any standard limited warranty is needed.

Part 2: Products

All the different cladding and support products used in the building should be called out and specified. If multiple products are used, they should be identified by type in the specifications, and the locations of each type needs to be clearly called out in either the drawings or specifications. The details of the specified products can include the following:

  • The specific type, size, and shape of the HPL panels should be identified for each product used. The maximum yield from the panel manufacturer’s standard sizes result in cost-effectiveness and green design.
  • The specific performance criteria for each product including thickness, dimensional stability, surface characteristics, and any other needed criteria can be specified.
  • The specific color, pattern, and texture of each product needs to be called out. Manufacturer’s literature should be consulted for this as with any finished product.
  • Other requirements including the details of cleaning and stain removal for the product can be called out.

In addition, all trim, accessories, fasteners, and related items need to be identified in the specifications based on compatibility with the support system and wall assembly, ideally as part of a complete, coordinated system.

Part 3: Execution

As with any site-installed product, the installation requires multiple steps that need to be clearly articulated in the specification to achieve the best results.

Examination and preparation: The importance of this step should always be stressed. In addition to the architect, the installer should review and examine the wall substrate for conditions that may affect the installation or overall performance of the wall. Any issues will need to be corrected if they are found to be out of compliance with stated requirements.

Installation: The aluminum support system and HPL panels are commonly secured in place according to the manufacturer’s instructions and installation manuals. These should be consulted to assure that the facade system is installed to meet the code and conditions for a successful project.

Protection: Once installed, the rainscreen system should be able to withstand normal weather and human activity but should be protected from any remaining construction work that could adversely affect it.

Cleaning: Upon completion, the facade should be cleaned of any construction or miscellaneous dirt, debris, etc. as the manufacturer may suggest.

When specified and installed correctly, the facade system will provide the desired look and long-term performance characteristics that are intended.


HPL cladding panels have been shown to be an appealing solution for designing ventilated rainscreen building facades and related design components. The varied and extensive range of design characteristics provide architects with broad design freedom and many opportunities for creativity. The tested and demonstrated performance characteristics help assure that the material will function as intended over the life of the building. The process of supporting and installing the system is straightforward and economical. The materials and systems support sustainability goals and can be specified to meet project requirements on a wide range of building types. Architects who become familiar with and incorporate this proven system can reap all of the benefits that HPL facades offer.

The information in this course is given with the best intention, but no rights can be derived from the content.

Peter J. Arsenault, FAIA, NCARB, LEED AP, is a nationally known architect and prolific author of more than 230 continuing education courses advancing building performance through better design. www.pjaarch.com, www.linkedin.com/in/pjaarch


Trespa Trespa North America Ltd. is recognized as a premier developer of quality exterior panels for cladding and decorative facades. With a focus on product development and manufacturing technologies, Trespa delivers innovative, aesthetically pleasing, and high-performance products. For additional information, visit www.trespa.com.


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Originally published in February 2021