Polyurethane Window and Door Jamb Selection & Design Guide
Learn how to select polyurethane window and door jambs, calculate profile ratios, combine crowns, and follow correct architectural application methods.
Polyurethane Material Specifications and Physical Properties
Polyurethane window and door jambs are produced from rigid, closed-cell polyurethane foam with a density range of 150-220 kg/m³ (production target ~160 kg/m³) and a standard production target of approximately 150-220 kg/m³ (production target ~160 kg/m³). This closed-cell structure limits water absorption to under 1%, preventing freeze-thaw degradation on exterior facades. The material withstands thermal conditions from -100 °C / +80 °C without warping or dimensional loss. It is essential to note that these profiles and matching columns are strictly decorative components and do not carry structural architectural loads.
Calculating Profile Width using the 8-12% Proportion Rule
Sizing a window jamb requires maintaining correct visual balance relative to the wall opening. A standard architectural guideline dictates that the jamb profile width should equal 8% to 12% of the overall window or door opening width. For instance, a window measuring 100 cm in width requires a jamb profile between 8 cm and 12 cm wide. Using undersized jambs weakens facade depth, while oversized profiles visually overcrowd wall spaces.
Combining Jamb Profiles with Pediments and Crowns
Enhancing window head details involves combining linear jamb profiles with decorative pediments or crown moldings (söve taçı). When integrating top crowns, the horizontal projection of the crown should match or slightly exceed the outer edge of the side jambs. Because polyurethane components are non-load-bearing, crowns must be independently secured to the structural wall behind them rather than resting their weight entirely on vertical jamb pieces.
Substrate Preparation and Mechanical Installation Rules
Proper installation of window jambs begins with a clean, dry, and dust-free masonry or plastered surface. Profile corners must be joined using precise 45-degree miter cuts. Bonding requires a polyurethane (PU) assembly adhesive applied along the rear contact surface; standard silicone adhesives are strictly prohibited due to inadequate structural shear strength. In addition to chemical bonding, mechanical fixing with corrosion-resistant screws is mandatory to anchor the jambs securely against wind loads.
Joint Preparation, Sanding, and Exterior Paint Application
Once mechanical fixings and adhesive have cured, screw counter-sinks and profile joints must be filled with exterior-grade putty. After drying, smooth these filled areas using 180-220 grit sandpaper. Polyurethane jambs are delivered factory pre-primed, making additional primer coats optional depending on surface preparation needs. Finally, applying two coats of high-quality, UV-resistant exterior paint is mandatory to protect the polyurethane material from direct solar radiation and weather exposure over time.
