{"id":"wpc-tech100-article-021-en","slug":"cap-layer-thickness-mapping-in-co-extruded-wpc","locale":"en","url":"https://woodplasticcomposite.net/guides/cap-layer-thickness-mapping-in-co-extruded-wpc/","title":"Cap-layer thickness mapping in co-extruded WPC","answer":"A capped WPC profile should be described by more than a nominal skin thickness. A thickness map helps identify how coverage varies around corners, grooves and other geometrical features.","author":"NFC & WPC Knowledge Reference","faqIds":["wpc-tech100-faq-021-en"],"tagIds":[],"noindex":false,"related":["wpc-tech100-article-022-en"],"version":1,"modified":"2026-10-15","reviewer":"","sections":[{"id":"technical-context","text":"A single measurement at the centre of the upper face cannot represent an entire perimeter. Local geometry and process behaviour can produce a distribution. Measurement uncertainty also matters when the layer is thin relative to the inspection method.","heading":"Technical context","references":[],"url":"https://woodplasticcomposite.net/guides/cap-layer-thickness-mapping-in-co-extruded-wpc/#technical-context"},{"id":"verification-plan","text":"Agree where sections will be taken and how the layer boundary will be identified. Record minimum, maximum and location-specific observations rather than reporting only an average. Keep representative images tied to the batch and profile revision.","heading":"What to measure and document","references":[],"url":"https://woodplasticcomposite.net/guides/cap-layer-thickness-mapping-in-co-extruded-wpc/#verification-plan"},{"id":"practical-decision","text":"Use the map with performance evidence, not as an independent durability rating. A thicker layer is not automatically the better system. Changes to the cap material or its distribution should be checked against the intended exposure and product specification.","heading":"Implications for development and specification","references":[],"url":"https://woodplasticcomposite.net/guides/cap-layer-thickness-mapping-in-co-extruded-wpc/#practical-decision"},{"id":"reading-scope","text":"Research on co-extruded coatings for composite durability. Use the linked work as related reading. The practical checks above are editorial recommendations, not reported test results or a substitute for product qualification.","heading":"Related reading and evidence limits","references":[1],"url":"https://woodplasticcomposite.net/guides/cap-layer-thickness-mapping-in-co-extruded-wpc/#reading-scope"}],"seoTitle":"Cap-layer thickness mapping in co-extruded WPC | WPC Reference","topicIds":[],"published":"2026-10-15","tableText":"Review step | Evidence to retain\nMaterial and geometry | Exact specimen or product identity\nVerification | Method, conditions and individual observations\nDecision | Approved scope and documented limitations","takeaways":"A single measurement at the centre of the upper face cannot represent an entire perimeter.\nAgree where sections will be taken and how the layer boundary will be identified.\nUse the map with performance evidence, not as an independent durability rating.","aiAssisted":true,"categoryId":"wpc-tech100-category-1","reviewedAt":"","change_note":"New focused technical draft; not a product certification or production recipe.","description":"A capped WPC profile should be described by more than a nominal skin thickness.","heroImageId":"","referenceIds":["wpc-tech100-ref-cap"],"review_status":"AI-assisted English editorial draft. Human technical review has not been recorded.","table_caption":"Evidence checklist for cap-layer thickness mapping in co-extruded wpc","seoDescription":"A capped WPC profile should be described by more than a nominal skin thickness.","translationGroup":"wpc-tech100-021-2026","references":[{"url":"https://research.fs.usda.gov/treesearch/28811","type":"web","title":"Co-extruded coatings for WPC durability","noindex":false,"accessed":"2026-10-14","seoTitle":"Co-extruded coatings for WPC durability","publisher":"USDA Forest Service","description":"Related reading; scope and limitations are identified in each article.","seoDescription":"Related reading; scope and limitations are identified in each article."}],"faqs":[{"question":"What evidence is needed for cap-layer thickness mapping in co-extruded WPC?","answer":"Agree where sections will be taken and how the layer boundary will be identified. Record minimum, maximum and location-specific observations rather than reporting only an average. Keep representative images tied to the batch and profile revision."}]}