SIS 440 Teak Deck Caulking: Why Primer-Free Application Matters
A practical guide to primer-free application, marine performance and estimating the caulk quantity for your teak deck.
A teak deck needs a caulking compound that can withstand sunlight, weather and movement while maintaining a clean finish. SIS 440 from Teakdecking Systems (TDS) is a one-part, neutral-cure teak-deck caulking developed specifically for this application.
One of its clearest advantages is straightforward: SIS 440 requires no separate primer on properly prepared teak. Combined with flexibility, UV resistance and a sandable finish after full cure, this makes it a practical choice for new teak decks, seam repairs and re-caulking.
No primer: one less stage in the job
Some marine caulking systems require a primer before the seam sealant is applied. That adds a product, an application stage and the primer’s specified drying time. SIS 440 removes that separate stage from properly prepared teak seams.
The benefit is a simpler application sequence. It does not mean that seams can be filled without preparation or that the deck is ready for finishing immediately. Surface preparation and full curing remain essential; follow TDS instructions for the complete process.
Flexibility where the deck needs it
Teak deck seams must accommodate movement. SIS 440 cures into a flexible sealant that bonds to correctly prepared seam walls, helping the joint respond to changes in the deck.
Designed for exposed marine decks
TDS documents resistance to UV exposure, ozone and temperature changes. These properties matter on deck, where caulking is exposed to sunlight and weather. Correct installation and appropriate deck care remain part of long-term performance.
A clean finish after curing
After full cure, SIS 440 can be trimmed and sanded to produce an even seam finish. It is available in black, gray and white. White and gray cure more slowly than black, so finishing schedules must follow the guidance for the selected color and application conditions.
Used in TDS’s own deck production
Teakdecking Systems uses SIS 440 in its own deck manufacturing and describes batch testing as part of its quality-control process. The product is used in deck construction as well as maintenance and refit work.
An excellent choice for hot, tropical climates
SIS 440 is an excellent choice for teak decks in hot, tropical climates. Its UV resistance, flexibility and temperature stability after curing are valuable on boats exposed to strong sun and heat, including those operating along Mexico’s coasts.
For decks where Sikaflex caulking has developed problems in very hot conditions, SIS 440 offers a practical re-caulking alternative, with no primer required on properly prepared teak. Successful replacement still depends on removing the old caulk, preparing the seams correctly and following TDS application instructions.
The caulk we use at OTA
At OTA—Odesa Teca Artesanos, part of PLC Marine Group—we use only SIS 440 for caulking teak deck seams.
For a new deck or a restoration project, the seam finish is part of the overall result, alongside the layout and condition of the teak. Explore OTA’s custom teak-deck work and see OTA projects on Instagram.
Primer-free still means proper preparation
A primer-free formula does not remove the need for clean, dry, correctly prepared teak. Old caulk, residue and contamination must be removed, and seam walls must be prepared and cleaned according to TDS instructions.
- Prepare the joint. Follow the manufacturer’s requirements for seam dimensions and bond-breaker tape.
- Fill the seam. Apply the caulk without trapping air, following the specified application method.
- Allow a full cure. Plan trimming and sanding around the selected color, seam dimensions and application conditions.
SIS 440 is a deck-seam caulking, not a below-waterline sealant. Paint and varnish do not adhere permanently to its cured surface. Read the TDS technical data and application guidance before beginning work.
How much SIS 440 does your project need?
Estimate the material from the total seam length, width and depth. For a deck with uniform, parallel planks, the calculator also offers an estimate using net deck area and plank width. Calculate areas with different seam dimensions separately.
The calculator allows for extra material used during application and rounds package quantities up. Its cartridge and sausage results are alternative ways of supplying the same estimated volume. Check the actual seam dimensions and available pack sizes before ordering.
Calculate your SIS 440 quantity
Enter your measurements below.
Enter all measurements to see your estimate.
Package quantities are rounded up.
TDS recommends 20–25% additional material for the application crown and tooling losses. This calculator includes 25% by default. The two package quantities are alternatives; you do not need both.
The deck-area method estimates long seams between uniform, parallel planks. End joints, borders and changes in layout may require additional material. Measure unusual layouts directly.
Seam-volume calculations and 305 mL / 592 mL package sizes follow Teakdecking Systems’ caulk yield calculator. Deck-area estimation is an additional PLC Marine planning tool. Check actual seam dimensions and pack sizes before ordering.
Plan your teak-deck project with PLC Marine
Whether you are repairing a few seams or planning a full re-caulk, start with the condition of the deck, the seam dimensions, the selected color and the quantity required.
Contact PLC Marine to discuss SIS 440 for your project in Mexico and confirm packaging and availability. You can also explore our Teakdecking Systems range for deck installation and maintenance.