Decking shims

This is a set of shims and drilling templates I designed as I was building stairs for my deck (2 steps). They also ensure a 5 mm spacing between boards for expansion.

In France, the sections for standard boards are 145 mm x 27 mm or 120mm x 27 mm while joists come in 70mm x 45mm.  Joists are usually used with the wider part horizontal but can also be used like beams (mostly when supporting other joists).

If you have different boards in your country, these shims / drill templates should still work as they ensure a constant screw hole distance to the edge of the boards (22.5 mm).

For my stairs I used both types of boards, the bigger ones horizontally and the smaller ones for the nosing.

I also did some double joisting meaning that joists can be on top of another joist.

That's why there are 4 types of shims:

• a T shim (can be used in both directions, with a sliding spacer in the middle)
• a L shim (to be used on the sides)
• a small U shim (used between joists, 45 mm wide)
• a big U shim (used between joists, 70 mm wide)

The L and T shims can be used for boards or joists. The T shim can be shortened by cutting the external pods.  If your joists are a bigger you should be able to adapt the U shims by cutting the positioning teeth on one side (or both).

The shims are basically a set of round pods linked together at the top.

The correct way to position them is to put the link part on top so that ventilation can dry the lower joist. 

The are also screw holes that allow to keep them in place when you need (mostly when used vertically, but also when you need to start at a specific place where the shim won't be blocked naturally). You should use 3.5x20mm pozdriv screws for that purpose. The main screws for the boards are 5x60mm while you need longer ones for joists (5x80mm).

The shims are 5 mm high to provide sufficient ventilation and are not intended to do the leveling… You need to achieve this with other means (other shims or adjustable screws).

I case you need to add a 3 mm shim to get a board leveled, you need to put it on top of the ventilation shim.

The drill templates (middle and external templates) are used for assembling the joists and the boards. For the joists, use the 2 external screws holes; for the boards use the central screw hole.

The drill templates also have specific holes for the nosing. In case you are simply using this for you deck (no stairs) you won't use those.

Printing:

Print in PETG preferably (heat tolerance and also some flexibility)

No supports are need.

Because the pods are used in compression, I used a 3 perimeters and 80% infill setup at 0.3 layer height.

The drill templates can be printed in PLA with default settings.