Mount expansion bolts in a slightly too thin wall...

[yens]

I am going to install an awning and according to the instructions, it should be installed in at least 90mm deep holes in the concrete. However, my concrete walls are only 85mm thick, so I will drill through if I try to drill 90mm.

In other words, there are a few options:

- Drill all the way through since it apparently allows drilling deeper than 90, and secure the expansion bolt in the approximately 85mm available.

- Drill shallower and hope it holds.

- Install some form of plate that is perhaps 25mm thick, both to be able to mount it with a couple of extra fastening points, and to make the hole as deep as it should be.

What does the expertise think is the best way to go?

Thanks in advance!

 

[huggan]

No problem having through holes with expansion bolts, but you must absolutely not drive it in too far as it won't hold. I think that's enough without any other solutions.

 

[Pumba]

Drill straight through and place a large washer and nut on the backside?

 

[smedbror]

Use concrete screws (Hilti's 10mm house screw). Buy longer ones and cut them to your exact length. Usually, 90mm are available on the shelves. Also, the screw head looks nicer. Last time I checked, I think they surpassed expansion bolts in shear and tensile strength.

 

[Alej]

Why not drill 70mm deep, use chemical anchor and insert threaded rods?