Polyurethane Pediments Selection and Installation Guide

Polyurethane pediments engineered for interior and exterior architectural applications are manufactured from high-density rigid polyurethane featuring a closed-cell physical structure. The raw material density ranges strictly between 150-220 kg/m³ (production target ~160 kg/m³), with a standard factory production target of approximately 160 kg/m³. This high-density construction limits water absorption to below 1%, rendering the profiles impervious to moisture ingress, rot, and swelling.

For projects across different climate zones in Europe, material thermal tolerance is a critical parameter. Rigid polyurethane pediments withstand continuous ambient temperatures from -100 °C up to +80 °C without experiencing cross-sectional warping or volumetric degradation. Polure manufactures these decorative elements in compliance with international transit and safety requirements, utilizing dense export packaging designed to prevent corner damage during multi-country logistics. Note that all decorative pediments and accompanying decorative columns are non-load-bearing elements and must never be subjected to structural load paths.

Selecting the correct pediment profile requires evaluating the proportion between the wall opening width and the overall header height. A pediment that is too small appears visually lost, whereas an oversized cross-section creates unbalanced top-heavy proportions. For standard door frames ranging from 80 cm to 100 cm in width, pediment heights between 15 cm and 25 cm maintain optimal architectural balance.

When calculating required material quantities for a project, precise perimeter measurements are required:

• Measure the outer width of the window or door casing, including any lateral architraves.
• Add a 5 cm to 10 cm overhang margin on each side if the pediment is designed to extend beyond the vertical side trim.
• Include a standard 10% to 15% material allowance to account for miter cuts and physical installation waste.

Proper surface preparation is mandatory to ensure permanent adhesion of polyurethane pediments to structural substrates. The receiving wall or frame surface must be completely dry, structurally sound, and free from dust, grease, or flaking plaster. Smooth or painted walls should be lightly abraded to optimize the mechanical bond of the adhesive layer.

Cutting pediments requires high-precision equipment to achieve tight joints across project sites:

• Use a fine-tooth miter saw or a dedicated profile cutting box to execute clean 45-degree angle cuts.
• Maintain consistent blade speed to prevent edge burning or localized foam tearing during the cut.
• Verify cut alignments on a flat layout surface prior to applying chemical adhesives.

Installing polyurethane pediments requires a combination of chemical bonding and mechanical anchoring. The primary bonding agent must be a dedicated polyurethane (PU) assembly adhesive. The use of standard silicone sealant is strictly forbidden, as silicone lacks the tensile bonding strength required for permanent architectural attachment and fails under thermal expansion stress.

In addition to PU assembly adhesive, mechanical fixing with stainless steel or coated screws is mandatory. Screws anchor the pediment into the underlying wall studs or masonry anchors while the structural adhesive cures. Screws should be countersunk 2 mm below the profile surface to allow for seamless flush patching during the finishing phase.

Polyurethane pediments leave the factory with a standard pre-applied primer coating. While this initial layer protects the surface during transit, applying an additional job-site primer layer is optional based on the specific paint system chosen by the applicator. The manufacturer does not claim that additional priming is entirely unnecessary under all environmental conditions.

To achieve a smooth final appearance, complete the following surface preparation sequence:

• Fill all countersunk screw heads and joint seams using an exterior-grade acrylic or polyurethane masonry filler.
• Allow the filler to cure completely, then sand the joints smooth using 180-220 grit sandpaper.
• Wipe away all sanding dust before applying finishing coats.
• Apply at least 2 coats of high-quality topcoat paint.

For exterior installations anywhere in the European market, utilizing a paint system with high UV resistance is mandatory. Standard interior paints will degrade, yellow, and chalk under direct sunlight, compromising the protective barrier of the polyurethane profile.

To prevent site delays and structural failures when specifying Polure pediments, follow this pre-purchase verification protocol:

• Confirm that the substrate is strictly non-structural and that the pediment will carry no vertical loads.
• Verify that ambient installation temperatures fall within the stable operational range of the PU adhesive.
• Inspect packaged items upon arrival to verify transit integrity across long-distance freight routes.
• Ensure that PU assembly adhesive and appropriate mechanical fasteners are ordered alongside the decorative profiles.
• Avoid using silicone, unanchored mounting, or non-UV exterior paints, as these constitute the primary causes of field failures.