loading

How do I anchor a handrail into old concrete?

Cement is an ingredient of concrete.
I'm trying to put a small grab-rail onto my Mom's front patio, which has concrete aggregate rocks of about 0.5cm-2.5cm. It's classic, old concrete slabs. IT IS NOT PURE CEMENT.
My question is: What's the best way to anchor, say, a handrail, into it. It appears to be fragile. Thanks.  

Picture of How do I anchor a handrail into old concrete?
sort by: active | newest | oldest

Use epoxy set screws, don't use expansion screws

You can get a fastener, where you drill a hole, clean the dust out, drop a bottle of epoxy in, smash it with the screw, and wait until the epoxy cures.

+1

blkhawk2 years ago

You can make holes with a hammer drill and masonry bits. You could use Tapcon® screws or other screws with lead or plastic expansions.

Well, if it is truly fragile, then maybe you could just knock a big hole in it, Then fill the big hole with your steel anchor(s), plus some new, strong, concrete.

That's a little bit different strategy than these suggestions of drilling small holes, in the old concrete, then filling the small holes with anchor(s) + epoxy.

Actually for either strategy, you probably want to start with a small hole. The name of the tool that makes that small hole is called a "masonry bit"

http://en.wikipedia.org/wiki/Drill_bit#Masonry_dri...

You know, it's a drill bit, but one made for really hard materials like stone, brick, concrete, etc. I guess in Australia they call it a "stone bit".

Anyway, this first step, of the first hole you drill, this will reveal how "fragile" your concrete is. In my experience, trying to cut or drill through concrete is an exercise in patience, because concrete is this really hard stuff that takes a lot of work to cut through it.

If your concrete is strong, not fragile, you'll put a lot of work into just drilling a few small holes in it, and in that case, the small holes approach is the way to go, because it would take all day to make a big hole in strong concrete.

First get a rail with the right mounting plate.
Make sure all is aligned and in the right place, mark the holes you need in the concrete for the mounting plate.
Now to figure out how good the concrete is:
Use a small stone drill (5-6mm) and drill a hole on one of your markings.
The dust coming out should be dry and light grey to almost white, if it is very dark it is a sign of moisture.
The drilling should give you a fair resistance, the longer it takes to get the hole done the better the concrete - which means by using normal pressure on the drill.
The hole should go for at least 10cm before the drill punches throut to soil.
If the above is all good you can use normal conrete anchor bolts, the metal type that tightens by pulling a cone into it when fastening the nut.
If the concrete is far to easy to drill but still dry you won't get enough strength to fix a handrail safely.
Here you use the mentioned epoxy type anchors.
For weak concrete I found that misusing the drill to create a bigger hole diameter in the bottom part gives added strenght - but for this the anchor should be at least 10cm deep in the concrete, thin 5cm slabs can't be fixed with epoxy anchors.
If the slab is quite thin you are better off drilling a hole through the concrete and into the ground, should be the right diameter for pipe that fits into your handrail.
Drive a lenght of pipe through the hole and into the ground - the concrete will now only secure the pipe against sideway movements while the support is given from the ground.
Place your handrail over this pipe and secure in place with a quick weld or with a screw going through both pipes. Of course for better looks you can tap the inner pipe and use a short screw...