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Not the actual product photo. Real product photography coming soon. Specifications and pricing below are accurate.
ThermoClip™ ExtremeTC®
Specialized hidden fastener engineered specifically for thermally modified lumber. Accommodates the unique expansion and contraction properties of heat-treated wood.
Gap Spacing
Varies by wood type
Key Features
- Designed for Thermo Ash, Thermo Pine, Thermo Red Oak
- Handles different expansion rates of thermo-modified wood
- Corrosion-resistant construction
Kit Contents
175 clips, 175 #8x2" SS screws, T15 bit
Installation Tip
Ensure proper joist spacing of 16″ on center maximum for thermally modified lumber.
ThermoClip™ hidden deck fasteners are engineered specifically for thermally modified wood decking—Ash, Pine, Spruce, and other heat-treated softwoods that behave differently than traditional lumber. The smooth polyethylene construction and 1/4" gap spacing allow thermally modified boards to expand and contract freely without the stress fractures common with rigid metal fasteners. The hardened stainless steel insert prevents screw over-driving while maintaining maximum holding strength. The 90-degree screw installation holds decking tight to joists while accommodating the unique movement characteristics of thermal wood. 175-piece kit covers 100 square feet with all hardware included.
Available Options
Choose your preferred options and quantity below.
Standard 1/4" gap
175 Kit
TC-175
$152.70
per unit
About this product
The DeckWise ThermoClip™ ExtremeTC® is a high-strength hidden fastener designed specifically for thermally modified wood and dense tropical hardwood decking. It features a stainless steel insert molded inside a UV-resistant thermoplastic body to provide maximum hold-down power while allowing for natural wood expansion and contraction. This fastener solves the problem of unsightly surface screws and ensures a clean, professional finish for high-end outdoor projects.
Manufacturer Specifications
- Gap Size
- 1/4 inch (6.35 mm)
- Fastener Material
- UV-Resistant Polypropylene with Stainless Steel Insert
- Screw Material
- 304 Grade Stainless Steel
- Drive Type
- T15 Star Drive
- Coverage Rate
- Approximately 100 sq. ft. per 175-count kit (16 inch O.C.)
- Compatible Board Thickness
- Standard 5/4 inch and 1x (3/4 inch) decking
Best used for
- 1Residential Ipe or Cumaru decks where a smooth, fastener-free surface is required for aesthetics and safety.
- 2Rooftop Tigerwood or Garapa installations where consistent 1/4-inch spacing is critical for proper drainage and airflow.
- 3Commercial boardwalks or pool surrounds using Massaranduba or Red Balau to provide a corrosion-resistant and bare-foot friendly surface.
Pro tips for dense hardwoods
- Even with self-drilling screws, always pre-drill a pilot hole through the fastener and into the joist when working with extremely dense species like Ipe to prevent screw shearing.
- Ensure your tropical hardwood is fully acclimated to the local humidity for at least 7-14 days prior to installation to minimize board movement after the clips are secured.
- Use a BoWrench or similar board-straightening tool to hold boards tight against the clips while driving the screws to ensure perfectly straight gaps.
Specifications
- Brand
- DeckWise
- Category
- Hidden Fasteners
- Kit contents
- 175 clips, 175 #8x2" SS screws, T15 bit
Per-option details
| Option | SKU | Piece count | Dimensions | Weight |
|---|---|---|---|---|
| Standard 1/4" gap | TC-175 | 175 Kit | — | — |
Piece counts and dimensions are as supplied by the manufacturer for each package option.
Why Choose Hidden Fasteners?
How Hidden Fasteners Work on Hardwood Decks
Pre-Groove the Boards
Hidden fasteners require a slot machined into the edge of each board. Most boards from Ipe Woods USA ship pre-grooved, or you can route the slot on-site with a 1/8″ slotting cutter.
Set the First Board
Secure your starter board to the joist with a face screw near the house-side edge. This first board anchors the rest of the field and will be covered by trim.
Clip, Screw, Slide
Insert the clip into the board groove, drive the supplied screw through the clip into the joist at roughly 45°, then slide the next board onto the exposed clip tab. The built-in spacer legs set the gap automatically.
Repeat Across the Deck
Continue across the deck, one board at a time. Each clip grips the outgoing board while spacing the incoming one — no measuring or shimming needed.
Pro Tip from Our Deck Specialists
In hot weather, tighten clips snugly but not crushing-tight. Exotic hardwoods expand and contract with moisture changes, and the clip must allow sideways movement to prevent buckling.
Hidden Fasteners — Common Questions
Frequently Bought Together
Accessories that pair well with hidden fasteners for a complete installation.
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Expert Support
Call 1-844-674-4455