{"id":3267,"date":"2025-06-04T13:35:59","date_gmt":"2025-06-04T13:35:59","guid":{"rendered":"https:\/\/ikoknowledgecenter.com\/docs\/uncategorized\/how-is-a-bituminous-waterproofing-membrane-installed-on-a-rough-or-uneven-concrete-surface\/"},"modified":"2025-06-23T08:58:41","modified_gmt":"2025-06-23T08:58:41","password":"","slug":"how-is-a-bituminous-waterproofing-membrane-installed-on-a-rough-or-uneven-concrete-surface","status":"publish","type":"docs","link":"https:\/\/ikoknowledgecenter.com\/en\/docs\/flat-roof-systems\/how-is-a-bituminous-waterproofing-membrane-installed-on-a-rough-or-uneven-concrete-surface\/","title":{"rendered":"How is a bituminous waterproofing membrane installed on a rough or uneven concrete surface?"},"content":{"rendered":"\n

Installing a bituminous waterproofing membrane on a rough concrete surface<\/strong> requires the right approach, depending on the degree of roughness. An uneven surface can negatively affect the adhesion, durability, and watertightness of the roofing system.<\/p>\n\n

The appropriate method depends on the surface roughness<\/strong> of the concrete. Below, we explain what to do in different situations:<\/p>\n\n

1. Roughness less than 2 mm<\/strong><\/span><\/h4>\n\n

If the surface roughness is less than 2 mm<\/strong>, you can start by applying a suitable bitumen primer and then directly install a standard 3 mm vapour barrier.<\/p>

In this case, it is also possible to apply the top layer directly (e.g. IKO roofgarden<\/strong><\/a> or IKO summa<\/strong><\/a> 4 mm). These membranes are robust enough to absorb minor surface irregularities.<\/p><\/p>\n\n

2. Roughness between 2 and 4 mm<\/strong><\/span><\/h4>\n\n

If the surface roughness is between 2 and 4 mm<\/strong>, it is recommended to install an additional base layer. After applying the primer, a base membrane of 3 or 4 mm thickness should be installed. Suitable options include IKO base P3 T\/F<\/strong><\/a> or IKO base P4 T\/F<\/strong>.<\/p>

Afterwards, you can apply the desired top layer as the final waterproofing membrane (e.g. IKO roofgarden<\/strong><\/a> or IKO summa<\/strong><\/a> 4 mm). This combination ensures a safe and durable build-up despite the slightly rough surface.<\/p><\/p>\n\n

3. Roughness greater than 4 mm<\/strong><\/span><\/h4>\n\n

For concrete surfaces with a roughness greater than 4 mm<\/strong>, it is essential to level the surface first.<\/p>

In this case, we advise applying a cementitious<\/strong> screed or another appropriate levelling layer before applying the primer and bituminous membranes. This ensures optimal adhesion and prevents long-term damage to the roofing membranes.<\/p><\/p>\n\n

For more information, contact your IKO advisor.<\/p>\n","protected":false},"excerpt":{"rendered":"

Installing a bituminous waterproofing membrane on a rough concrete surface requires the right approach, depending on the degree of roughness. An uneven surface can negatively affect the adhesion, durability, and watertightness of the roofing system. The appropriate method depends on the surface roughness of the concrete. Below, we explain what to do in different situations: […]<\/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":[952,307,867,869],"class_list":["post-3267","docs","type-docs","status-publish","hentry","doc_category-flat-roof-systems","doc_tag-foundation-en","doc_tag-roofing-en","doc_tag-substrate","doc_tag-top-layer"],"year_month":"2026-07","word_count":260,"total_views":"771","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":"foundation","term_url":"https:\/\/ikoknowledgecenter.com\/en\/docs-tag\/foundation-en\/"},{"term_name":"roofing","term_url":"https:\/\/ikoknowledgecenter.com\/en\/docs-tag\/roofing-en\/"},{"term_name":"substrate","term_url":"https:\/\/ikoknowledgecenter.com\/en\/docs-tag\/substrate\/"},{"term_name":"top layer","term_url":"https:\/\/ikoknowledgecenter.com\/en\/docs-tag\/top-layer\/"}],"knowledge_base_info":[],"knowledge_base_slug":[],"_links":{"self":[{"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/docs\/3267","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=3267"}],"version-history":[{"count":1,"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/docs\/3267\/revisions"}],"predecessor-version":[{"id":3268,"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/docs\/3267\/revisions\/3268"}],"wp:attachment":[{"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/media?parent=3267"}],"wp:term":[{"taxonomy":"doc_category","embeddable":true,"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/doc_category?post=3267"},{"taxonomy":"glossaries","embeddable":true,"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/glossaries?post=3267"},{"taxonomy":"doc_tag","embeddable":true,"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/doc_tag?post=3267"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}