Mounting heavy bikes onto wall - screws failed, advise appreciated

[Livi]

Hey,

Relatively new DIYer here and this is my first post, any advice for this problem gratefully received!

I'm mounting OSB strips and hooks onto the party wall in the alcove of my Victorian terraced house. The idea is to hang bikes up from their front wheels.
The walls are 9 inch oooold crumbly brick with 2cm of old crumbly plaster over the top.

There should be three hangers side by side with the middle one about 20cm higher than the outer two - staggered so the bike handlebars don't tangle together.
I'm attaching pictures of what happened to the middle one - when I hung bikes from all three the middle one failed and pulled out of the wall taking a big load of plaster with it.

I've now realised (I think) that this is because the screw was nowhere near deep enough in the wall:
The screws I used were 60mm long, and I used red rawl plugs.
The plaster itself is 20mm thick.
The OSB+hook is 25mm thick.
So my screw was only 15mm into the brick, whereas I think for such a heavy item it should be at least 40mm into the brick (so the screws need to be at least 20+25+40mm long = 85mm)
I think the one that's failed was actually in the mortar not the brick, but reckon it's a matter of time before the others fail too.

So here's my idea for a remedy:
1. Remove all the existing plugs and drill deeper holes and insert 100mm frame fixings like these instead - https://www.screwfix.com/p/rawlplug...ck/73814#product_additional_details_container
2. Fix the broken plaster with Ronseal Big Hole smooth finish filler, which I can then drill into, slightly lower than the existing hole I've drilled

Any advice on whether this is a good idea or I need to consider something else would be really appreciated.
Also any advice on how to carefully remove the existing red rawl plugs without damaging the plaster.

Thanks a lot and sorry for the lengthy q!

 

[Lower]

You can just drill the existing plugs out when you drill a deeper hole for the new fixings. If a masonry drill won't take them out, use a normal drill bit just to clear the plastic plugs out of the hole.

 

[Deleted member 174758]

I notice you didn't state the screw size (other than length), but red plugs (5.5mm holes) suggest 4.0 or 4.5mm. I'd go brown plugs, 7mm holes, 6.0 x 100 or 6.0 x 120 screws. Double plug the holes if necessary. No need for frame fixings

 

[freddiemercurystwin]

If I was the OP I'd use the fixings he linked to but they can be bought from Screwfix in a smaller pack.

 

[Livi]

I notice you didn't state the screw size (other than length), but red plugs (5.5mm holes) suggest 4.0 or 4.5mm. I'd go brown plugs, 7mm holes, 6.0 x 100 or 6.0 x 120 screws. Double plug the holes if necessary. No need for frame fixings

Thanks. Screws were 5mm.

 

[Livi]

If I was the OP I'd use the fixings he linked to but they can be bought from Screwfix in a smaller pack.

Yep I'm inclined to do this because of the weight of the bikes. And I'll need 3 per strip, for 6 strips, so may as well buy the 25 pack and have a few spares.
Also I'm she/her but its no biggie

 

[opps]

Double plug the holes if necessary.

For the benefit of the OP. Double plugging means drilling a hole deep enough to accept two lengths of plug (collarless).

There is little to be gained from drilling really deep holes and using long screws if the plug is substantially shorter. If you only use one plug and try to bury it deep in to the brickwork, when you tighten the screw, it may just end up pulling the plug in to the plaster zone (and up to the reverse side of the OSB).

I would follow @JobAndKnock 's post.

BTW, regarding your strips of OSB, from a mechanical loading point of view, it would make more sense to have the bike fittings at the lower end of the OSB rather than the top of the OSB, but I appreciate that might be less aesthetically pleasing.

 

[opps]

Oh, and I would avoid the Ronseal deep hole filler. Premixed fillers in tubs cure via evaporation, from the surface inwards. It may take days for it to harden.

Two pack filler will harden in about 15 mins at this time of this year. The deeper the hole, the faster it sets (because it generates more heat)

eg https://www.screwfix.com/p/ronseal-high-performance-wood-filler-white-550g/45077

IMO the Ronseal stuff is massively overpriced. I use Upol Easy 1 which I buy via Ebay for just over £20 for 3.5L Vs the £80 for the equivalent volume of the Ronseal version.

It is more difficult to sand though, so if you use it, make sure that it is pretty flush. You can then use a softer filler to fill the breakout visible either side of the OSB strip.

Alternatively, look at something like Toupret TX100. It is a powder based filler. It contains cement, the addition of water means that a chemical reaction speeds up the curing time. A hole that deep whilst not completely dry, means that you could drill after a couple of hours.

 

[Livi]

Thanks for all that opps. I already have the ronseal filler and I have a loada time on my hands this week so I've gone ahead and done that. I'll give it a few days to dry before drilling.
With regard to the double plug rather than the frame fixings, is the advantage just cost? Because to me it looks as though the wall plug is almost as long as the screw so no issue with the hole being way longer than the plug. Or am I missing something?

 

[opps]

Thanks for all that opps. I already have the ronseal filler and I have a loada time on my hands this week so I've gone ahead and done that. I'll give it a few days to dry before drilling.
With regard to the double plug rather than the frame fixings, is the advantage just cost? Because to me it looks as though the wall plug is almost as long as the screw so no issue with the hole being way longer than the plug. Or am I missing something?

It is primarily a cost thing. You are now paying almost a quid per fixing. Double plugging would be 80(?)% cheaper. There is nothing wrong with your chosen fixings though.

In reality, given that you are only filling around one hole, provided that you upgrade the other fixings, If I were you, I would remove the OSB, fit the deeper fittings, and then tap the new one through the front of the OSB (using an appropriate counter sink to bury the collar and screw). That way you won't need to worry about the "deep fill" filler being too soft..

You will be drilling a 10mm hole, so don't worry about the old 5mm red plug being in the way.

 

[Livi]

Tap the new one through the front of the OSB (using an appropriate counter sink to bury the collar and screw). That way you won't need to worry about the "deep fill" filler being too soft..

You will be drilling a 10mm hole, so don't worry about the old 5mm red plug being in the way.

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.

 

[Livi]

BTW, regarding your strips of OSB, from a mechanical loading point of view, it would make more sense to have the bike fittings at the lower end of the OSB rather than the top of the OSB, but I appreciate that might be less aesthetically pleasing.

The bikes will have to be hung on the hanger vertically from their top wheel and the strip of OSB is to protect the wall so can’t move the fitting sadly!

 

[Deleted member 174758]

A point about frame fixings - AFAIK they were originally introduced to fix PVCu window frames in place. This is because a metal screw put straight into a PVCu frame could damage the PVCu, whereas the sheath (plug) which goes right up to the head means there is no metal to PVCu contact. In addition, though, because they are designed to hold a window in place, they are primarily designed to resist sideways pressure (of, say, wind on the window) and so may not offer good straight pull-out resistance. Lastly, they require a 10mm hole, which is getting a bit big for many DIY drills and bits, but well within the capabilities of an SDS drill

The 7mm hole with brown plugs and 6mm screws is a proven method for securing materials to walls, concrete, etc with known pull-out properties. It is cheap and readily available (our local ironmonger sells plugs by the dozen and screws individually). I don't believe in spending excessive money when it simply isn't necessary (typical tightwad joiner). Whilst I suggested 6mm screws, I did so to maximise the strength of the fastenings to well above what is required to hold the weight of a bicycle, and in fact 5.0mm screws of the same length would do the job and require only a PZD#2 screwdriver (6.0 screws need a PZD#3) although with 5mm screws I'd suggest is that a penny washer (aka repair washer, mudguard washer) might be added beneath each screw head. Hardwood plywood would be a better choice than OSB for strength and durability

The double plugging thing is to deal with ropey masonry. Yes, OP, you are right to place your holes in the middle of a brick or block, but sometimes even then you don't get the best of grips, so removing the screw, pushing in a second plug, then rescrewing can be necessary. This is most often required on old Victorian buildings, etc with ropey bricks or stone, but it can happen that you need to resort to this on modern blockwork, too

 

[Livi]

A point about frame fixings - AFAIK they were originally introduced to fix PVCu window frames in place. This is because a metal screw put straight into a PVCu frame could damage the PVCu, whereas the sheath (plug) which goes right up to the head means there is no metal to PVCu contact. In addition, though, because they are designed to hold a window in place, they are primarily designed to resist sideways pressure (of, say, wind on the window) and so may not offer good straight pull-out resistance. Lastly, they require a 10mm hole, which is getting a bit big for many DIY drills and bits, but well within the capabilities of an SDS drill

The 7mm hole with brown plugs and 6mm screws is a proven method for securing materials to walls, concrete, etc with known pull-out properties. It is cheap and readily available (our local ironmonger sells plugs by the dozen and screws individually). I don't believe in spending excessive money when it simply isn't necessary (typical tightwad joiner). Whilst I suggested 6mm screws, I did so to maximise the strength of the fastenings to well above what is required to hold the weight of a bicycle, and in fact 5.0mm screws of the same length would do the job and require only a PZD#2 screwdriver (6.0 screws need a PZD#3) although with 5mm screws I'd suggest is that a penny washer (aka repair washer, mudguard washer) might be added beneath each screw head. Hardwood plywood would be a better choice than OSB for strength and durability

The double plugging thing is to deal with ropey masonry. Yes, OP, you are right to place your holes in the middle of a brick or block, but sometimes even then you don't get the best of grips, so removing the screw, pushing in a second plug, then rescrewing can be necessary. This is most often required on old Victorian buildings, etc with ropey bricks or stone, but it can happen that you need to resort to this on modern blockwork, too

This is a great explanation. Any recommendations for collarless wall plugs? It'd be hard to tap the rawlplugs I use into the wall because of the collar. Was thinking of these - https://www.screwfix.com/p/plasplugs-solid-wall-fixing-7-x-40mm-50-pack/3947k

 

[freddiemercurystwin]

The fixings the OP linked to originally will be absolutely fine here.