Screw holes in reinforced concrete

[GB]

My garage used to be an air raid shelter, built during the last war out of reinforced concrete.

I now want to put up shelving screwed to the walls. I have a reasonably powerful 'ordinary' hammer drill, mains powered. Black and Decker, but fairly sturdy. This is fine for brickwork, but I'm not so sure about concrete. Is this going to be man enough for the job, or should I buy/hire something more powerful?

Also, do I need a special drill bit or will an ordinary masonry drill bit do the job?

Thanks very much for any help/advice you can give.

G

[Chris Bacon]

Give it a go, and see what happens. "Drillability" depends on what the concrete is made of, as well as the drill!

A masonry bit will do the job - make sure it's not a blunt one!

[EricP]

Any hammer thing should do, but an SDS will eat it. The problem you have is in the word "reinforced".

Metal in the wall will simply destroy the drill bit. Use a metal detector and try to avoid places where it is found.

[tony sayer]

In article , GB writes

Go out and buy a decent SDS and you'll wonder how you EVER managed before without one!!!!

Theres a very good Makita one around the 100 quid mark or just less comes with some useful bits and chisels:))

[UkJay]

Hello GB I'm no diy expert, but I did put up some stuff to enable me to hang up my tools in the Garage, so the same technique may apply here.

If you can manage to fasten strips of wood to your walls with a couple of screws or whatever, you only need to screw into the strip rather than into the wall afterwards.

Ok this wasn't reinforced concrete so GOOD LUCK

James (UkJay)

[Guy King]

The message from "GB" contains these words:

Glue battens to the walls and fix the shelves to them. Provided you're sensible about the areas involved you'll have no trouble at all. A couple of 3' long bits of 4x2 well stuck up with no-more-nails-alike will take loads of weight.

But, if you must drill it, get a cheap SDS drill (they're about £30). It'll sail through it, and usually comes with a useful selection of adequate quality bits.

[John Rumm]

Try it and see how far you get - you may be ok with what you have. A SDS drill will romp through it *much* faster. However even that may stop making progress if you hit a substantial bit of rebar burried in the concrete.

A standard masonry drill will do for most cases. If there is loads of rebar reinforcement in there, then you could try one of the specialist rebar drill bits, or one of the Bosch multimaterial drill bits (these will drill concrete and metal without being damaged - note that you don't want hammer action on the metal though)

[dennis]

It can be quite dangerous drilling rebar. Some panels are pre-stressed and odd things happen if you fracture the rebar. Ever seen concrete explode before?

[The Natural Philosopher]

Hire a hilti gun....

[nightjar]

I don't know whether the stuff hardens with age, or they used different mixes back then, but IME wartime mass concrete is particularly difficult stuff to drill.

...

Even for putting holes in modern concrete, I go to a hire shop and get something with lots of oomph.

Colin Bignell

[EricP]

It's a chemical reaction that keeps working-the stuff keeps hardening.

Diamond drill anyone??