Removing broken screws from concrete ...

[Jethro]

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.

[Lobster]

[...]

Assuming the broken screws are flush with the surface[1] and not causing anyone any harm, then I'd leave them the hell alone! If and when they ever do really need to come out, then worry about it at then - with luck it will never happen. (Read the current thread where loads of folk have successfully attached their lavvies to the floor with just silicone)

David

[1] If not, then you've guessed it - ANGLE GRINDER time!

[MuddyMike]

I agree 100%.

One time I absolutely had to remove a coach screw that was sheared off level with a concrete post I used the old engineers trick of puddle welding a square of steel to the stub and using it like a new head. In theory the same trick would work with steel screws in a concrete floor.

Mike

[Tabby]

Easiest is just to angle grind them off below the surface. If you want holes in the same place, thus must get them out, I'd try tapping them sideays in all directions, hoping it may break up the cement round them. Or the blowtorch, but putting a heatproof mat down on the screed.

[The Medway Handyman]

If you can get mole grips on, then use them to unscrew rather than pull or lever.