Which masonry fixing should I use?

A masonry fixing fails for one of three reasons: the wrong plug for the substrate, a hole that is too big, or dust left in the hole.

Step by step

1. Identify the substrate.Dense brick, aerated block, dense concrete block, poured concrete or lime-mortared old brick all behave differently. Drill dust colour and how easily it drills tells you a lot.
2. Use nylon plugs for light to medium loads.Shelving, brackets, battens in solid brick. Cheap, reliable, and adequate for most domestic fixing.
3. Use lightweight block plugs in aerated blockwork.Thermalite and similar crumble around ordinary plugs. Purpose-made spiral or helical fixings for aerated block grip properly.
4. Use frame fixings for frames.Long sleeved fixings driven through the frame into the masonry in one operation. Correct for door and window frames and much stronger than a plug and screw.
5. Use sleeve or expansion anchors for heavy loads.Wall-mounted TVs, gates, heavy brackets, structural work. They expand against the hole under load and are far stronger than nylon.
6. Use resin anchors near edges or in old masonry.Chemical resin injected into the hole with a threaded stud. It applies no expansion force, so it works close to edges and in soft or perished mortar where an expanding plug would split the brick.
7. Drill the exact stated diameter.The plug packet states the drill size. A hole even 1mm oversize means the plug never grips properly, and this is the commonest cause of a failed fixing.
8. Clear the dust out.Blow it out or vacuum it. Dust acts as a lubricant and dramatically reduces holding power, especially with resin anchors where it prevents bonding entirely.
9. Drill deeper than the plug.10mm or so of extra depth gives the dust somewhere to go and lets the plug seat fully.
10. Fix into brick, not mortar, for heavy loads.Mortar is much weaker, and old lime mortar has very little strength. For light fixings mortar is acceptable and easier to make good.

Tips

• Clear the dust from the hole. It is the single most common cause of a fixing that pulls out.
• Drill exactly the size on the packet — 1mm oversize halves the holding power.
• Resin anchors apply no expansion force, so they work where a plug would split the brick.

Common mistakes

• Using ordinary plugs in aerated blockwork — Thermalite and similar blocks crumble under expansion pressure, so the plug spins in an ever-enlarging hole. Use purpose-made lightweight block fixings.
• Fixing heavy loads into mortar joints — Mortar is substantially weaker than brick and old lime mortar has almost no strength. For anything heavy, fix into the brick itself.

If it doesn't work

Questions people ask