Sealants are a building’s first line of defence against water ingress, air leaks, and structural movement damage. Over time, UV exposure, thermal expansion, substrate movement, and improper installation cause sealants to crack, shrink, or detach — compromising both performance and appearance.
Our Joint & Sealant Defect Repairs service provides end-to-end rectification, ensuring joints are fully restored to their intended performance standard using the correct product for each application.
1. Sealant Condition Survey
We begin with a systematic inspection of all sealant lines, classifying each joint by:
- Failure mode (cohesive failure, adhesive failure, or substrate delamination).
- Whether the failure is localised or systemic.
- Exposure conditions and movement requirements.
- Suitability of the existing sealant type for its application.
2. Full Removal & Substrate Preparation
All failed sealant is mechanically removed — never overcoated. Substrate edges are cleaned to bare material, solvent-wiped, and primed in accordance with product manufacturer requirements and AS 4654.2. Applying new sealant over old is the most common cause of rapid re-failure, and we never permit this practice.
3. Product Selection & Application
We select sealant products based on:
- Joint type: Expansion, control, construction, or glazing.
- Substrate: Concrete, masonry, aluminium, glass, or membrane.
- Movement capacity: The joint’s expected thermal and structural movement range.
- Paintability & aesthetics: Whether the joint will be painted or left exposed.
Typical products include: paintable polyurethane for facade movement joints, structural silicone for glazing, and low-modulus silicone for wet-area junctions.
4. Bond Testing & Quality Sign-Off
After application and cure, we conduct field adhesion pull tests on representative sections to confirm bond integrity before closing out the works. All sealant repairs are documented with product data sheets, photos of preparation, application, and testing.
By combining correct product selection, meticulous preparation, and documented quality verification, Atomic Projects’ joint and sealant repairs restore the building envelope to its intended watertight performance.
Frequently Asked Questions
How long do building sealants typically last?
Most high-quality silicone and polyurethane sealants have a service life of 15–25 years in normal conditions. However, UV exposure, thermal cycling, substrate movement, and incorrect installation can dramatically shorten this. Sydney’s climate is particularly demanding — seals on north and west-facing facades typically degrade faster than sheltered internal joints.
What is the correct process for removing and replacing failed sealants?
Old sealant must be fully removed (not just overcoated) using mechanical tools and solvents, and the joint substrate must be cleaned, primed, and dried before new sealant is applied. Applying new sealant over old is a common short-cut that causes rapid re-failure. AS 4654.2 and product manufacturer requirements govern the preparation standard.
What sealant types are appropriate for different applications?
Silicone sealants are typically used for glazing and wet-area joints; polyurethane sealants are preferred for movement joints in concrete and masonry facades due to their paintability and abrasion resistance; butyl and EPDM tapes are used in specific roofing and cladding applications. Product selection must account for joint width, movement capacity, substrate, and exposure conditions.
How do failed sealants cause water ingress?
Sealants bridge the gap between different building elements — facade panels, window frames, expansion joints, penetrations. When they fail (cracking, shrinking, debonding), water enters through these joints and can travel unseen within the building fabric before emerging as internal dampness or staining. Sealant failure is one of the most common causes of water ingress in multi-storey buildings.
Can joint and sealant repairs be done without scaffolding?
In some cases, rope access or EWP (elevated work platform) can be used for high-level facade sealant works where access is straightforward. For extensive facade resealing programmes, scaffold or swing-stage may be more economical and safer. Atomic Projects assesses the best access method for each project based on building height, geometry, and scope.
Related Services
Ready to address defects in your building? Atomic Projects is a Class 2 Registered Builder with over 10 years of specialist experience in remedial and defect rectification works across Sydney. Contact our team to discuss your project and arrange a site inspection.
