I'm putting up a wall mounted holder for my road bike and the istructions say that the bolts must go into brick, not mortar. There are three bolts and they are quite randomly placed (i.e not in a row).

I would usually use trial and error but in this instance because of the arrangement of bolts I could end up with lots of holes in my wall.

Is there a way to find where brick/mortar is behind plaster before drilling the holes for the bolts?

  • 1
    Does your plaster wall cover a brick wall? If you don't know then there may not be any brick there.
    – ArchonOSX
    Apr 9, 2016 at 11:18
  • yes it's a victorian house, definitely brick
    – Sean Toru
    Apr 9, 2016 at 11:23

3 Answers 3


If you are talking about supporting a bicycle then 100 year old mortar will certainly hold your bike especially with three anchors.

I would just put the anchors where I wanted them and not worry about hitting brick. However, with a running bond pattern, and measuring the brick dimensions from the outside, whether your first anchor hits brick or not you should be able to measure from there to hit brick on the two subsequent anchors.

Good luck!

  • Agreed. Even if your bike was made of pig iron, 3 marginal anchors would work fine. Apr 9, 2016 at 16:43

just ignore the instructions. use threaded rods set into resin anchors. this way it doesnt matter if you hit mortar or masonry. its basically glue in a hole that holds the anchor. you can get gun type, syringe type or glasscap type resins. they all work pretty much the same way, but have different pros and cons. just google it or check youtube.


You'd have to be very unlucky to get all three in mortar. The chances are if you hit mortar it's a horizontal line, so with a little care you can have a good chance of avoiding getting a second hole into mortar, depending on the hole pattern.

Decent fixings (rawlplugs) into mortar are probably stronger than the rubbish supplied with most things into brick anyway, so get decent fixings.

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