How to choose
Choose a sealant around movement, moisture, paintability and the two joint surfaces.
Quick answer
Treat the joint as a moving interface, not a gap to fill. Record the two surfaces, expected movement, water exposure, paint requirement and whether an old sealant must be removed first.
Scope: Confirm substrate, load direction, edge distances and maker data; safety-critical or structural fixings need competent design.
Four options to compare
Best for: Low-movement gaps around trim and decorating work that will be painted.
Main trade-off: Decorator caulk is not a wet-area or high-movement substitute.
Must check: Maximum joint size, drying time and paint compatibility.
Best for: Documented bathroom or kitchen joints around supported non-porous surfaces.
Main trade-off: Poor preparation, joint geometry or movement can still cause early failure.
Must check: Surface compatibility, mould-resistance claim, cure and water-exposure time.
Best for: Supported outdoor or higher-movement interfaces.
Main trade-off: Some products are not paintable or compatible with every plastic, stone or coating.
Must check: Movement class, weather exposure, substrate primer and service temperature.
Best for: A regulated or performance-critical assembly.
Main trade-off: A visually similar cartridge is not an interchangeable product.
Must check: Use the specified tested system and competent installation route.
Old sealant, soap, moisture, loose paint and incorrect joint depth can defeat a suitable chemistry. Plan removal, cleaning and backing before opening the cartridge.
Brand families often contain acrylic, silicone, hybrid and specialist products. Use the exact product name and data sheet.
What this guide cannot check
Do not claim universal safety, guaranteed suitability, professional approval or permission to undertake protected work. Check current instructions, exact identifiers and local circumstances before acting.