How should I mount a 70kg load (server rack) to a wall?

[KnownGnome]

I’m planning to wall‑mount a 4cabling server rack in my garage, and once it’s populated it’ll be around 70kg. The wall is an internal plasterboard stud wall; the exterior of the house is brick veneer. The rack has a rear hinge, though I don’t expect to swing it open often.

Questions:

• Can I wall‑mounted for this weight?
• Planning to mount a structural plywood backing board across 2-3 studs, then mount the server rack to that. What fixings into timber studs are best (coach screws/bolts, washer types, plywood backing board)?
• And how thick should the structural plywood be (12mm, 15mm, 17mm, 19mm)?
• Are there Australian standards or best practices I should follow for mounting heavy equipment to studs?

I’m moving in next week, so I’ll confirm stud spacing soon. Thanks for any guidance or examples from similar installs!

P.S.: I've attached an image of what I'd imagine the installation will be like. Disclaimer: the image is AI-generated using an existing image of our garage, with the server rack inserted into the image.

[MitchellMc]

Welcome to the Bunnings Workshop community @KnownGnome. It's brilliant to have you join us, and many thanks for your question about mounting to a wall.

That’s a good, well-thought-out approach, and yes, mounting a 70kg server rack on a stud wall can absolutely be done safely if it’s detailed properly.

Using a structural plywood backing board across multiple studs is exactly what I’d be doing in this situation. Given the weight involved and the fact the rack is hinged, I’d recommend going straight to 19mm structural plywood. Thinner sheets like 12 or 15mm can work for lighter loads, but at 70kg plus dynamic forces when opening the rack, 19mm gives you stiffness, better screw holding, and far more margin for error. If you’re building it once, it’s worth overbuilding slightly for peace of mind.

For fixing plywood to timber studs, standard bugle-head timber screws are a good choice. Something in the order of 14g screws, around 100mm long, will give you plenty of embedment into the stud once you account for the plasterboard and plywood thickness. I’d aim for at least four fixings per stud, spaced vertically, and spread the board across two studs at an absolute minimum, three if your stud layout allows it. That spreads the load very nicely and keeps deflection to a minimum.

In terms of standards, there isn’t a specific Australian Standard for mounting to residential wall studs. This falls more under general structural fixing best practice rather than a regulated installation. As a reference point, 70kg spread across multiple studs is not an unreasonable load at all, especially when it’s distributed via a structural backing board. Timber studs can comfortably handle this sort of load when the fixings and load spread are done correctly.

Here's a helpful guide: How to hang just about anything.

Please let me know if you have any questions.

Mitchell
 

[KnownGnome]

Thanks, Mitchell! Helpful and exactly the kind of detail I needed.

One follow‑up: for mounting the server rack to the plywood itself, what screw/bolt type and size would you recommend? Coach screws vs coach bolts with nuts/washers?

Appreciate your knowledge.

[MitchellMc]

That depends on the size of the holes in the server rack, @KnownGnome. Coach screws could be used, or if you were to position bolts through the plywood at the correct spots before mounting it, bolts. I'd go with bolts, but that can be a bit more fiddly to get all lined up correctly.

Mitchell