{"id":4296,"date":"2025-10-14T09:58:03","date_gmt":"2025-10-14T09:58:03","guid":{"rendered":"https:\/\/ikoknowledgecenter.com\/docs\/uncategorized\/can-bituminous-roofing-membranes-be-applied-directly-over-pvc-roofing-membranes\/"},"modified":"2026-09-15T11:56:30","modified_gmt":"2026-09-15T11:56:30","password":"","slug":"can-bituminous-roofing-membranes-be-applied-directly-over-pvc-roofing-membranes","status":"publish","type":"docs","link":"https:\/\/ikoknowledgecenter.com\/en\/docs\/flat-roof-systems\/can-bituminous-roofing-membranes-be-applied-directly-over-pvc-roofing-membranes\/","title":{"rendered":"Can bituminous roofing membranes be applied directly over PVC roofing membranes?"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">No. PVC consists of various components, including plasticisers, which keep the roofing membrane flexible.<\/p>\n\n<p class=\"wp-block-paragraph\">Over time, however, plasticiser loss may occur. The plasticisers migrate out of the product, causing it to lose its flexibility.<\/p>\n\n<p class=\"wp-block-paragraph\">Direct contact with bituminous roofing membranes accelerates this phenomenon. Direct contact between the two materials is therefore technically not recommended.<\/p>\n\n<p class=\"wp-block-paragraph\"><p class=\"isSelectedEnd\"><span style=\"text-decoration: underline;\">To avoid this, we recommend two options:<\/span><\/p><\/p>\n\n<ol class=\"wp-block-list\">\n<li>Apply a <strong>separation layer<\/strong> over the PVC roofing membrane before installing the bituminous roofing membranes.<\/li>\n\n\n\n<li>Use an underlay that is bituminised on one side, with <strong>polyester on the underside<\/strong> (e.g. <a href=\"https:\/\/products.ikopro.com\/products\/download\/191\/en\/I\" target=\"_blank\" rel=\"noopener\">IKO base 460P60<\/a> or <a href=\"https:\/\/products.ikopro.com\/products\/download\/192\/en\/I\" target=\"_blank\" rel=\"noopener\">IKO base 360P60<\/a>). This should be used as the first layer of the bituminous roofing system installed over the PVC roofing membrane.<\/li>\n<\/ol>\n\n<p class=\"wp-block-paragraph\"><strong>Please note!<\/strong><\/p>\n\n<p class=\"wp-block-paragraph\"><p class=\"isSelectedEnd\">Bonded bituminous roofing systems cannot be applied directly over PVC. Only mechanically fastened or loose-laid, ballasted bituminous roofing systems can be used.<\/p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>No. PVC consists of various components, including plasticisers, which keep the roofing membrane flexible. Over time, however, plasticiser loss may occur. The plasticisers migrate out of the product, causing it to lose its flexibility. Direct contact with bituminous roofing membranes accelerates this phenomenon. Direct contact between the two materials is therefore technically not recommended. To [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","template":"","meta":{"footnotes":"","_members_access_role":[],"_members_access_error":""},"doc_category":[63],"glossaries":[],"doc_tag":[974,849,65,876,934,906,867],"class_list":["post-4296","docs","type-docs","status-publish","hentry","doc_category-flat-roof-systems","doc_tag-compatibility-en","doc_tag-fastening-method","doc_tag-flat-roof","doc_tag-renovation-en","doc_tag-roof-construction","doc_tag-roof-system","doc_tag-substrate"],"year_month":"2026-09","word_count":142,"total_views":"2","reactions":{"happy":"0","normal":"0","sad":"0"},"author_info":{"name":"Luna Degraeve","author_nicename":"luna","author_url":"https:\/\/ikoknowledgecenter.com\/en\/author\/luna\/"},"doc_category_info":[{"term_name":"Flat roof systems","term_url":"https:\/\/ikoknowledgecenter.com\/en\/docs-category\/flat-roof-systems\/"}],"doc_tag_info":[{"term_name":"compatibility","term_url":"https:\/\/ikoknowledgecenter.com\/en\/docs-tag\/compatibility-en\/"},{"term_name":"fastening method","term_url":"https:\/\/ikoknowledgecenter.com\/en\/docs-tag\/fastening-method\/"},{"term_name":"Flat roof","term_url":"https:\/\/ikoknowledgecenter.com\/en\/docs-tag\/flat-roof\/"},{"term_name":"renovation","term_url":"https:\/\/ikoknowledgecenter.com\/en\/docs-tag\/renovation-en\/"},{"term_name":"roof construction","term_url":"https:\/\/ikoknowledgecenter.com\/en\/docs-tag\/roof-construction\/"},{"term_name":"roof system","term_url":"https:\/\/ikoknowledgecenter.com\/en\/docs-tag\/roof-system\/"},{"term_name":"substrate","term_url":"https:\/\/ikoknowledgecenter.com\/en\/docs-tag\/substrate\/"}],"knowledge_base_info":[],"knowledge_base_slug":[],"_links":{"self":[{"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/docs\/4296","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/docs"}],"about":[{"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/types\/docs"}],"author":[{"embeddable":true,"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/comments?post=4296"}],"version-history":[{"count":1,"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/docs\/4296\/revisions"}],"predecessor-version":[{"id":4297,"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/docs\/4296\/revisions\/4297"}],"wp:attachment":[{"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/media?parent=4296"}],"wp:term":[{"taxonomy":"doc_category","embeddable":true,"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/doc_category?post=4296"},{"taxonomy":"glossaries","embeddable":true,"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/glossaries?post=4296"},{"taxonomy":"doc_tag","embeddable":true,"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/doc_tag?post=4296"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}