Caulk
Caulk is filler material commonly used by decorators. Most caulks are more rigid than sealants, but more flexible than other fillers when they dry and can be used where movement or leakage can occur - as long as significant expansion or contraction is not anticipated.
Historically, caulk was made from fibrous materials that could be driven between boards, pipes and so on to make them waterproof. Rope caulks are still available and are primarily used to reduce drafts, and sound transmission, especially around windows.
Modern caulk is also waterproof. It is typically made from acrylics, vinyl or silicone. These materials dry quickly and remain relatively flexible. It can be used to close small gaps and crevices. It prevents air, insects, rodents and dust from compromising the integrity of seals, spaces and structures.
Acrylic caulk can be painted after it has dried completely. However, painted caulk can crack if it is applied in temperatures lower than four degrees Celsius. Silicone caulk cannot be painted.
Caulk is generally sold in cartridges that can be inserted into caulking guns. This technique helps to control the application process. If spills and smears occur during the process, they can be cleaned up with water rather than solvents.
It is possible to caulk over old acrylic caulk, unless the old caulk is oily, dirty or has deteriorated significantly (in which case, the new caulk will not adhere). Caulk should not be applied over old caulk that is wet or has mould or mildew.
[edit] Related articles on Designing Buildings
Featured articles and news
A now architectural practice looks back at its concept project for a sustainable oceanic settlement 25 years on.
Copyright and Artificial Intelligence
Government report and back track on copyright opt out for AI training but no clear preferred alternative as yet.
Embedding AI tools into architectural education
Beyond the render: LMU share how student led research is shaping the future of visualisation workflows.
Why document control still fails UK construction projects
A Chartered Quantity Surveyor explains what needs to change and how.
Inspiration for a new 2026 wave of Irish construction professionals.
New planning reforms and Warm Homes Bill
Take centre stage at UK Construction Week London.
A brief run down of changes intentions from April in an onwards.
Reslating an ancient water mill
A rare opportunity to record, study and repair early vernacular roofs.
CIOB Apprentice of the Year 2025/26
Construction apprentice from Lincoln Mia Owen wins this years title.
Insulation solutions with less waste for a circular economy
Rob Firman, Technical and Specification Manager, Polyfoam XPS explains.
Recycled waste plastic in construction
Hierarchy, prevention to disposal, plastic types and approaches.
UK Net Zero Carbon Buildings Standard V1 published
Free-to-access technical standard to enable robust proof of a decarbonising built environment.
Prostate Cancer Awareness Month
Why talking about prostate cancer matters in construction.
The Architectural Technology podcast: Where it's AT
Catch up for free, subscribe and share with your network.
The Association of Consultant Architects recap
A reintroduction and recap of ACA President; Patrick Inglis' Autumn update.
The Home Energy Model and its wrappers
From SAP to HEM, EPC for MEES and FHS assessment wrappers.
Future Homes Standard Essentials launched
Future Homes Hub launches new campaign to help sector prepare for the implementation of new building standards.
Building Safety recap February, 2026
Our regular run-down of key building safety related events of the month.
























Comments
[edit] To make a comment about this article, click 'Add a comment' above. Separate your comments from any existing comments by inserting a horizontal line.