While dismantling my spare loo to fit a combined waste/soil pipe (see posts passim !) I broke the screws I used to fit the loo and wooden paneling to the floor. Luckily I was able to unscrew two diagonally opposed screws on the loo, so I redrilled and used 2 no.6 bolts with
10mm heavy duty rawlplugs.Unfortunately I couldn't do anything with the 5 others that broke, so redrilled some holes about 3cm from them, and refitted the brackets.
I pity the poor sod who tries to drill holes where the broken screws are - although I suspect that when it needs maintenance or refurbishing, the poor sod will be me.
I did have the bright idea of trying to blast the screw/rawlplug combination with a blowtorch, in the vain hope the plastic would melt, and I could pull the whole assembly out. However, I suspect that because the concrete acts as a sodding big heatsink, the heat wasn't doing much - I certainly couldn't move anything.
Trying to drill the broken screws out was an abject failure - the drill slipped, went between the screw and rawlplug, and promptly broke. So now one of the screws has some HSS to add to the fun ;-)
What would people here do ? Or is the only guranteed answer to smash the concrete to pieces, and relay where needed ?
Had a similar thing in the bathroom last year, but that's a wooden floor, and it was easier to get some small mole grips on, and ease the stump out.