Dry lining boxes in the floorboards

[Jim K..]

Have you considered using ordinary metal back boxes & drilling holes in their sides to allow you to screw them to the edges of the floorboard hole?

[David]

Following advice I am mounting (or trying to) single 13 amp sockets with a flip lid into the floorboards.

I ordered Appleby dry lining boxes from Screwfix.

After a major struggle I managed to get the Cat5e faceplate into the first box, and worked out that the screw holes were not quite lining up because of the method of fixing into the hole.

The yellow tabs fold into the inside of the box, then fold out through the wall after you have inserted the back box through the hole.

I'm sure that I have used these successfully in plasterboard before.

The problem that I am seeing is that the yellow tabs don't quite fold into a vertical position - they toe in slightly - so whilst I can get the first screw in by offsetting the face plate a bit I can't get the second screw to take because the metal thread in the yellow tab is not quite vertical.

This is not helped by having to wrestle the sprung lid of the socket to get at the screw heads. Any raddling of the fitting lifts the plastic box and moves the orange tabs back down and at a far greater angle from vertical.

Has anyone found a smart way of doing this, or can recommend another brand of dry lining box which doesn't have this "fold out clip" arrangement?

TIA

Dave R

[David]

Just worked out what it is.

Box won't fit anything deeper than about 12.5mm - 15mm.

The floorboards are about 18mm.

So I have to trim a bit of plastic off each box.

I can see now that there isn't any depth specified for the shallow box, but the deep box says " Allows 6.35mm to 15mm plasterboard depth.".

So I have to trim about 3mm off the white plastic bits where the yellow tab clicks in.

Ho hum.

Dave R

[Andy Burns]

I was just about to suggest that floorboards are thicker than plasterboard ... will they have the strength to take being walked on?

[David]

The bit where the sockets are will not be walked on.

Under the centre of a purpose made desk close to a wall.

Cheers

Dave R

[David]

Yep - that worked.

Just need one more box and I'm done.

Mission creep with the Ethernet socket used up an extra dry lining box.

Cheers

Dave R

[ARW]

On the inside of the box?

[ARW]

Sorry just realised you said Appleby.

The modification for your needs is shown in this picture.

The right hand lug in the picture had been modified (in this case) with toe nail clippers. Two small snips and it is done.

[Mathew Newton]

Whilst a bit fiddlier to do, it is better to trim the white bits from the box as this then allows the locking tabs to still function. Nothing more annoying than inadvertently pushing the lugs away when trying to insert the screws!

[David]

I just gently trimmed the white strips inside with a small wood chisel until the space when it clipped in was about 20mm.

It worked fine.

Kicking myself for not seeing it sooner.

Cheers

Dave R

[Dave Plowman (News)]

Why on earth would you use dry lining boxes into floorboards? Screws through the side of a metal box would be simpler and neater.

[ARW]

Personally I would have bought dry liners that would have worked with a deeper finish. But then I already knew that.

However I learnt that lesson a long time ago in exactly the same way the OP learnt his.....

[Dave Plowman (News)]

Personally can't see the point in dry liners when going into thick wood? Only real reason for them is to get a fixing in something with little strength, like plasterboard.

[ARW]

For what it's worth we do not use them on new builds.

Noggins and metal back boxes every time.