Mounting heavy bikes onto wall - screws failed, advise appreciated

[opps]

Really appreciate your advice but I don’t understand what you mean - tap the plug through? And re the countersink do you mean ensure the head of the screw is buried in the wood?

And about the 5mm plug, I was gonna fix the new osb slightly lower as I’d inadvertently drilled into very old and pretty much perished mortar. So hope not to have to re-use the hole, just filling it for aesthetics.

Sorry for not being clear.

I meant that if you are going to use the fixings that you linked to, you can tap those in from the front of the OSB without needing to remove the OSB. If you do that though, you will need to countersink the holes to hide the fixing's nylon collar (and screw).

 

[JohnD]

If the bricks are a bit crumbly, or the hole is a bit loose:

Clean all the dust out with a Hoover or water jet (and let it dry)

Inject builders adhesive of the no-more-nails type (cheap own-brand is fine) into the hole, starting at the back so there is no air bubble behind it

Press your plasplug deep in, recessed slightly below the face of any plaster, and well into the brick (plaster has no strength)

You can put a long screw a turn or so into the plug as a handle, without expanding it

Leave it to set overnight

The next day you can drive in your screws and they will transmit the expansion pressure to the brick with no cracking

In wet conditions, or safety-critical heavy jobs, you can use resin anchors in a similar way, but greater cost.

BTW I don't like red plugs and always use brown ones, may be overkill sometimes but is plenty strong enough for most DIY.

 

[Livi]

Finally got this done, with the double plug technique and 6x100mm screws. Works great. Thanks everyone for the advice!