Preparing concrete floor for replacement WC

[dedge43]

I need to get a new WC installed in pretty much the same place as the old one, on what seems to be a concrete floor. The old WC became unusable because the floor screws and their rawlplugs worked loose, enlarging the mounting holes, and now it's been removed there are several holes of different depths on each side of where it used to be, presumably either from previous WCs or previous attempts to stabilize the last one.

So the area where I'd need to drill holes to mount the replacement WC is a bit of a mess. Can anyone advise on the best way to repair the concrete that will allow the new WC to be mounted securely? Should I enlarge the existing holes further before trying to fill them? If so, is there any special shape of (enlarged) hole that would work best? Or would it be better to chase away the whole area, fill it, and level off? I'd rather not go that far if it can be avoided, but if I have to, how deep should I go?

Would be grateful for any advice, especially from anyone who's had the same problem.

dedge43

 

[longdogs]

You could do it the old way which is to lay a mound of sand & cement onto the concrete then bed the pan onto it. Dissadvantage is that you will not be able to remove the pan without breaking it.

 

[dedge43]

Thanks, squeaky, hadn't thought of that and it might be the answer!

But I probably should have mentioned in the original post that although the new WC does have to be securely fixed, it's only going to be a temporary installation. With the prospect of guests over Christmas we need to get a working WC into this bathroom ASAP, but we also plan to have the whole bathroom remodelled sometime next year.

Does anyone have any experience of cleaning up old enlarged/redundant mounting holes as described above in a concrete floor? I was originally hoping to find some quick way of repairing the concrete so it could safely be drilled again. Because the temporary replacement WC will go have to go in the same position as the old one, i will probably have to drill the new holes in the same areas as before.

Dedge

 

[andytw]

Some new WCs are fixed sideways into a special fixing. The advantage is that you can al least sort out the fixing before placing the toilet.
http://www.screwfix.com/p/fischer-wb5n-wc-bidet-side-fixing-kit/65637

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