How to extend a pergola leg?

[deecay]

I’m assembling a small free-standing aluminium pergola and I need to raise the legs by just 20mm.

 

Each leg has a 160mm square, 10mm high detachable plate (pictured) with 3 holes for the bolts. Ideally I’d put some sort of 20mm square riser underneath and line up with equivalent drilled bolt holes.

What could I use that would support up to ~50kg per leg?

[JacobZ]

Hi @deecay,

Thank you for the question about how to raise your pergola legs by 20mm.

Assuming the pergola is going on the timber deck you mentioned in your previous post, the simplest option is to sit the legs on 2 of these Titan 20 x 72 x 100 mm White Packing Shims. They are 20mm thick, 100mm long and 72mm wide. When sat side by side, this will cover most of the post's footprint.

Alternatively, these Titan 20 x 150 x 100 mm White Packing Shims will also work and when placed side by side will support more of the footprint, but you'll have to cut one down, so they don't protrude past the edge of the plate.

If you're using screws, you can screw straight through them into the timber beneath. If you are using bolts, you'll have to predrill a hole through them for the bolt to go through.

These packers are designed to support 5 tonnes of compression so the 50kg per leg is not an issue.

Let me know what you think and if you have any further questions, please don't hesitate to ask.

Jacob

[deecay]

Thank you @JacobZ this sounds like a good idea - can the shims be easily cut with a circular saw?

 I’ll be using screws into the underlying timber frame/joists. Which screws would you recommend? Would I need to drill a pilot hole at least for the shims?

[MitchellMc]

Hi @deecay,

I'd suggest using a coach screws, which will require the shims to be pre-drilled with holes of the same diameter as the screw you select. The frame/joists will also need to be pre-drilled to slightly smaller than the threads on the screw. You only want the threads to bite into the timber.

The size of the holes in the mount will determine the screw you select. Something like a M8/12 at 75/100mm should be sufficient.

Please let me know if you have any questions.

Mitchell