{"product_id":"wienerberger-k209-blue-perforated-class-b-engineering-brick","title":"Wienerberger K209 Blue Perforated Class B 73mm Engineering Brick Pack of 368","description":"\u003ch3\u003eWienerberger K209 Blue Perforated Class B 73 mm Engineering Brick\u003c\/h3\u003e\n\u003cp\u003eThis brick is a perforated, extruded wirecut engineering unit designed for strength, moisture resistance, and structural use rather than appearance. Engineering bricks are classified by performance, not visual quality. Because clay and manufacturing can vary, mixing units from multiple packs is prudent to minimise tone variation.\u003c\/p\u003e\n\u003ch3\u003eKey Specifications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSize:\u003c\/strong\u003e215mm × 102.5mm × 73mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eColour:\u003c\/strong\u003eBlue\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTexture:\u003c\/strong\u003eSmooth, Perforated Wirecut\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWater Absorption:\u003c\/strong\u003e? 7%\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDurability:\u003c\/strong\u003eF2\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompressive Strength:\u003c\/strong\u003e? 75 N\/mm²\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePack Quantity:\u003c\/strong\u003e368\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eActive Soluble Salts:\u003c\/strong\u003eS2\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThermal Conductivity:\u003c\/strong\u003e0.840 W\/(m·K)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReaction to Fire:\u003c\/strong\u003eClass A1\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGross Dry Density:\u003c\/strong\u003e1800 kg\/m³\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSize Tolerance:\u003c\/strong\u003eT2\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRange Tolerance:\u003c\/strong\u003eR1\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eDescription \u0026amp; Usage Notes\u003c\/h3\u003e\n\u003cp\u003eThe **K209 Blue Class B** perforated engineering brick is engineered for high-load and moisture-critical environments such as foundations, retaining structures, or damp-proof courses. With a strong compressive strength of ? 75 N\/mm² and a low water absorption rating (? 7%), it performs reliably under demanding conditions. The F2 frost-resistance rating further supports its use in exposed applications. Because this is an engineering brick, surface appearance (colour, texture uniformity) is not the primary focus. For aesthetic facades, use a facing brick. Mix bricks from different packs to reduce visible variation. Use proper detailing—cavity design, flashing, drainage, mortar compatibility—to ensure longevity.\u003c\/p\u003e\n\u003ch3\u003eFAQs\u003c\/h3\u003e\n\u003ch4\u003eIs 7% water absorption acceptable for engineering bricks?\u003c\/h4\u003e\n\u003cp\u003eYes — for Class B engineering bricks, ? 7% absorption is standard and helps ensure durability in load-bearing and moisture-prone applications.\u003c\/p\u003e\n\u003ch4\u003eWhat does the F2 durability rating mean?\u003c\/h4\u003e\n\u003cp\u003eIt means the brick is frost-resistant and suitable for general UK external exposure. In extremely harsh or marine environments, higher durability classes or protective design may be advisable.\u003c\/p\u003e\n\u003ch4\u003eCan this engineering brick be used as a facing brick?\u003c\/h4\u003e\n\u003cp\u003eIt’s technically possible but not recommended. Engineering bricks aren’t manufactured for consistent visual quality, so for visible facades, a designated facing brick is usually a better choice.\u003c\/p\u003e\n\u003cp\u003eCheck out our full range of \u003ca href=\"https:\/\/jjbuildingmaterials.co.uk\/collections\/building-supplies\"\u003ebuilding supplies\u003c\/a\u003e.\u003c\/p\u003e\n\u003cp\u003eBrowse more \u003ca href=\"https:\/\/jjbuildingmaterials.co.uk\/collections\/bricks-blocks\"\u003ebricks \u0026amp; blocks\u003c\/a\u003e available online.\u003c\/p\u003e","brand":"Weinerberger","offers":[{"title":"Default Title","offer_id":51448303649110,"sku":"161977","price":600.44,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0905\/4509\/4998\/files\/wienerberger-k209-blue-perforated-class-b-73mm-engineering-brick-pack-of-368-8798272.jpg?v=1772656832","url":"https:\/\/jjbuildingmaterials.co.uk\/products\/wienerberger-k209-blue-perforated-class-b-engineering-brick","provider":"JJ Building Materials","version":"1.0","type":"link"}