ThermoClip™ ExtremeTC® by DeckWise — Hidden Fasteners for hardwood decking
DeckWise
Hidden Fasteners

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

Why Choose Hidden Fasteners?

Clean, screw-free deck surface
Allows natural wood expansion
Professional appearance
Faster installation than face-screwing

How Hidden Fasteners Work on Hardwood Decks

1

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.

2

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.

3

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.

4

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.

Ships Nationwide

Fast LTL freight delivery

Quality Guaranteed

Professional-grade products

In Stock

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Expert Support

Call 1-844-674-4455

Need Help Choosing the Right Accessory?

Our deck specialists have installed thousands of hardwood decks and can recommend the exact accessories for your project, species, and climate.