Mounting wifi access point to lath and plaster ceiling

Question

I'm currently wiring CAT 6 network cable throughout my house and am also installing several Ubiquiti NanoHD wifi access points on ceilings. The original house is a 1920s build and has lath and plaster ceilings; the 1990s extension uses plasterboard.

The fixing instructions offer two installation approaches:

• wall mount (though also recommended for plasterboard ceilings) - drilling four 6mm holes and using rawl plugs, plus an 18mm hole for the network cable:

• ceiling mount for drop ceilings - drilling four 3mm holes plus the 18mm hole and using a plate:

I intend to use the first approach for the plasterboard ceilings in the modern parts of the house, and my inclination is to use the second approach for the lath and plaster ceilings in the older part of the house since I do have access to the space above those ceilings.

However, drilling (in general) into lath and plaster gives me concern, particularly because of the horror stories I've seen of people trying to install recessed lights and the entire ceiling falling down and electricians saying "never again"!

My questions are:

1. Am I over-thinking this? Should I just go ahead and use the first approach throughout the home?
2. If I should use the second approach in the older parts of the house, do I need any thought as to where to drill the holes - e.g. should they be in the plaster gaps between the lath wherever possible, or should they be through the lath? I've seen conflicting guidance on this - arguing you don't want to disturb the lath, but that you don't want to disturb the bond and the "tails" of the plaster between the laths.

I could use Command Strips as a last resort as the devices only weigh 300g (10.6oz), but would still require the 18mm cable hole.

Answer 1

My house was built in the 1890's and is predominantly plaster & lathe. I've mounted everything from small pictures to 10' long by 8' tall shelving to the wall by simply running drywall screws into the wall. I've tried using a stud finder to find studs, but the lathe befuddles them. I simply drive a screw wherever I want to hang something and have never had a problem.

When mounting on plaster and lathe, I'd recommend simply driving screws through the mounting holes and into whatever they find to hit behind them. As small and light as these are, even if all 4 screws only find plaster, they'll still hold just fine.

Answer 2

I think you are indeed, as you suspect, overthinking this. Some things are OK to fudge a little with the install, I think this is one of them.

It's powered by PoE so if your mount ever did fail, there wouldn't be a wire with dangerous voltage dangling around.

It's in your home, so it's not subject to theft or vandalism like it might be in a campus environment.

If your network is like most home wifi networks, this device doesn't serve any critical life safety function.

This device is small and light. The wood lath in your ceiling - even if it's old and dried out and not as strong as it once was - will provide enough purchase on screws to secure the device. You might need longer screws than are provided with the device - maybe 1-1/4" wood screws - to get past the plaster into the lath.

Notice that the holes in the mounting plate are tapered / countersunk to accommodate the head of the screws. It would be tempting to use drywall screws, the big coarse threads would help hold in the thin and aged lath. But I think they will be a bit too big, so they won't sit flush, which may prevent you from getting the WAP to screw into the mounting plate.

A suggestion. I have mounted a lot of this brand access point. The worst thing about them is the retaining clip on the mount, especially on the smaller Nano models. It's really difficult to get that to let loose once the thing is mounted. I snap that clip off.

The second worst thing about them is getting the WAP to screw onto the mounting plate. Just be careful and patient and don't force it or you may do damage to your ceiling, no matter what method you use to attach it.