Fitting back box to crumbly blocks

[Zerax]

I had one of those horrible walls the other day... just a couple of back boxes to sink in but behind the plaster was like a nasty course textured block that just fell apart. No fixings were possible... even knocking a little wooden wedge in behind to give something to screw to didn't work.

Just wondering what everyone uses in this situation... I always keep a bag of rapid set sand/cement with me, but wondering if I'm missing a trick with something more modern, simpler and less messy.

 

[Pete999]

Slap in some strong Compo to bed the box in, Compo = sand and cement in 2 sand 1 cement ratios. that'll fix the box alright if it don't eat it away first.

 

[Zerax]

Thanks for all these suggestions... much appreciated. It's amazing learning from the older sparks...

 

[jackhammerJIM]

I have a small Milwaukee 12V one for nice gentle work. Managed to drill a 5.5mm hole 6mm away from an external brick corner today without any shattering.

Im too tight Andy to own an sds just for plugs and screws ...

 

[valleyelectrics]

i sometimes knock the rear knockouts out, and that gives you a bigger choice of where to drill into the wall. Then use a penny washer with the screw to secure.