DOWSIL™ F4 Mould Resistant Sealant Builds Long-term Clean Sealing System for Kitchens and Bathrooms in Hardcover Residen

A large domestic real estate enterprise undertakes hardcover projects for commercial residential buildings. Kitchens and bathrooms are key decoration areas. The joints around kitchen sinks, stoves, shower rooms, bathtubs, basins and toilets in bathrooms are exposed to high temperature, high humidity and constant water vapor all year round. In previous projects, ordinary sealants turned black, bred mould, shrank, cracked and peeled off within 1 to 2 years. Mould damaged indoor aesthetics and endangered residents’ health, leading to numerous complaints. Cracked sealants also caused water seepage and damaged walls and cabinets, resulting in high rework costs in the later stage.

To solve this common problem, the enterprise conducted comprehensive tests on mould resistance, environmental performance, adhesion and aging resistance of multiple kitchen and bathroom sealants in the new round of centralized procurement. Finally, DOWSIL™ F4 High Performance Kitchen and Bathroom Mould Resistant Sealant was selected as the designated sealant for all hardcover residences. As a one-part neutral room-temperature curing silicone sealant, it perfectly adapts to harsh humid environments of home decoration with excellent overall performance and compliance.

1. Substrate Preparation: Thoroughly remove old sealant, dust and oil stains on substrates such as tiles, aluminum alloys, ceramics, marbles and painted surfaces. For non-porous surfaces like glass and sprayed aluminum alloys, wipe with 75% alcohol or isopropyl alcohol, then dry with a clean cloth to ensure clean and dry bonding surfaces.
2. Joint Treatment: Install closed-cell polyethylene backer rods at the bottom of all gaps to control sealant depth, avoid three-sided adhesion and improve deformation resistance. Apply masking tape along gap edges for neat appearance after construction.
3. Sealing & Trimming: Cut the nozzle of the sealant tube at a 45° angle, and apply sealant evenly with manual or pneumatic caulking guns to fully fill gaps and adhere to both sides of substrates. The skin-over time is 30 minutes. Trim the sealant surface with a special convex tool before skin formation for a smooth finish, and remove masking tape immediately after trimming.
4. Curing & Maintenance: Do not touch the sealant surface within 48 hours after construction, and keep it away from chemical solvents such as detergents and bleach. Put the area into normal use after full curing. With the sag degree ≤ 3mm, the sealant will not sag on vertical and overhead surfaces, suitable for various irregular gaps in kitchens and bathrooms.

DOWSIL™ F4 complies with GB/T 1741-2007 and ASTM G21 Grade 0 Mould Resistance Standard, the highest mould resistance grade for building sealants. It can effectively inhibit common moulds such as Aspergillus niger and Aspergillus flavus in long-term humid environments and fundamentally prevent blackening and mould growth on sealant joints. It passes GB 18583-2008 with VOC content less than 4%, and has obtained three-star China Green Building Material Certification and China Green Product Certification. Its superior environmental performance meets high standards of home decoration, with no peculiar smell after application.

After curing, the sealant has a Shore A hardness of 25 and an elongation at break of 572%. With outstanding elasticity, it can deform with slight thermal expansion and contraction of walls and sanitary ware to prevent cracking and peeling. This batch of hardcover residences has been delivered for 3 years. Continuous inspection shows no mould, blackening, cracking or peeling on all sealant joints. The waterproof performance remains intact, and no water seepage or damp damage occurs on walls and cabinets, greatly improving owner satisfaction. In addition, it has strong adhesion to various home decoration substrates including tiles, ceramics, aluminum alloys, marbles and non-oily wood. Extra priming is rarely required, which simplifies on-site construction and improves overall efficiency of hardcover projects.