{"id":3269,"date":"2025-06-04T13:21:23","date_gmt":"2025-06-04T13:21:23","guid":{"rendered":"https:\/\/ikoknowledgecenter.com\/docs\/uncategorized\/can-a-vapour-barrier-be-installed-on-a-concrete-surface-that-is-not-air-dry-yet\/"},"modified":"2025-06-23T09:01:05","modified_gmt":"2025-06-23T09:01:05","password":"","slug":"can-a-vapour-barrier-be-installed-on-a-concrete-surface-that-is-not-air-dry-yet","status":"publish","type":"docs","link":"https:\/\/ikoknowledgecenter.com\/en\/docs\/flat-roof-systems\/can-a-vapour-barrier-be-installed-on-a-concrete-surface-that-is-not-air-dry-yet\/","title":{"rendered":"Can a vapour barrier be installed on a concrete surface that is not air-dry yet?"},"content":{"rendered":"\n

No, a vapour barrier and its corresponding primer should not be applied to a concrete surface that is not air-dry (i.e. if visible moisture is still present).<\/strong>
For the correct installation of a bituminous waterproofing system, it is essential that the substrate is dry \u2014 both on the surface and internally.<\/p>\n\n

Why is a dry surface important for a vapour barrier?<\/span><\/strong><\/h3>\n\n

Applying a vapour barrier or primer to a damp or still-curing concrete surface (such as freshly poured concrete or foamed concrete) can lead to several issues:<\/p>\n\n

    \n
  • Poor or failed adhesion<\/strong> of the primer and vapour barrier<\/li>\n\n\n\n
  • Blistering or delamination<\/strong> due to trapped residual moisture<\/li>\n<\/ul>\n\n

    That\u2019s why it\u2019s crucial that the concrete is fully air-dry<\/strong> before installing a vapour barrier.<\/p>\n\n

    How can you check if the concrete surface is still damp?<\/span><\/strong><\/h3>\n\n

    A visual inspection<\/strong> is a simple first step. Concrete or foamed concrete that is still drying often shows clearly visible dark patches<\/strong>. These areas indicate residual moisture or parts of the slab that are still curing.<\/p>

    A uniform light grey colour, without any dark spots or patches, generally indicates that the substrate is sufficiently dry.<\/p><\/p>\n\n

    Note:<\/strong> The commonly referenced theoretical drying time for fully cured concrete is approximately 28 days<\/strong>.<\/p>\n\n

    \"\"

    Example of foamed concrete with a partially wet and dry surface.<\/em><\/p>

    <\/p><\/figcaption><\/figure>\n\n

    For more technical guidelines on substrate dryness for roofing works, refer to Technical Note TV 280<\/strong> by Buildwise<\/strong>.<\/p>\n","protected":false},"excerpt":{"rendered":"

    No, a vapour barrier and its corresponding primer should not be applied to a concrete surface that is not air-dry (i.e. if visible moisture is still present).For the correct installation of a bituminous waterproofing system, it is essential that the substrate is dry \u2014 both on the surface and internally. Why is a dry surface […]<\/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],"doc_tag":[850,910,952,897],"glossaries":[],"class_list":["post-3269","docs","type-docs","status-publish","hentry","doc_category-flat-roof-systems","doc_tag-advice","doc_tag-blistering","doc_tag-foundation-en","doc_tag-vapor-barrier"],"year_month":"2026-10","word_count":230,"total_views":"393","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":"advice","term_url":"https:\/\/ikoknowledgecenter.com\/en\/docs-tag\/advice\/"},{"term_name":"blistering","term_url":"https:\/\/ikoknowledgecenter.com\/en\/docs-tag\/blistering\/"},{"term_name":"foundation","term_url":"https:\/\/ikoknowledgecenter.com\/en\/docs-tag\/foundation-en\/"},{"term_name":"vapor barrier","term_url":"https:\/\/ikoknowledgecenter.com\/en\/docs-tag\/vapor-barrier\/"}],"knowledge_base_info":[],"knowledge_base_slug":[],"_links":{"self":[{"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/docs\/3269","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=3269"}],"version-history":[{"count":1,"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/docs\/3269\/revisions"}],"predecessor-version":[{"id":3270,"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/docs\/3269\/revisions\/3270"}],"wp:attachment":[{"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/media?parent=3269"}],"wp:term":[{"taxonomy":"doc_category","embeddable":true,"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/doc_category?post=3269"},{"taxonomy":"doc_tag","embeddable":true,"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/doc_tag?post=3269"},{"taxonomy":"glossaries","embeddable":true,"href":"https:\/\/ikoknowledgecenter.com\/en\/wp-json\/wp\/v2\/glossaries?post=3269"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}