I used this product to space my pressure treated deck boards 1/8 inch apart because I wanted them to be closer than the standard 3/16 to quarter inch. To do that I spaced and stacked the deck boards (5/4 by six pressure-treated ) inside and out of the weather to dry the boards until the moisture content was 6%. In other words, I pre-shrunk the boards. I then primed and stained (solid color) 2 coats all 4 sides of the boards. I again spaced and stack the boards and let them dry for another two months. I use these spacers on the final install to control the gaps. I left them in place while pulling the minor bows and warps out of the board. I’ve used other spacers and shim’s before. This product is superior.