Correct Masonry Drill Bit For EXTERNAL WALL

[goffy]

I'm hanging a very heavy mirror on a wall that is plaster on brick or possibly plaster, then breeze block , then brick. Its a solid external wall anyway, I tried screwing into it before and got no further than about half an inch when I hit the brick/breeze block. So I've bought grey nylon plugs 10mmx50mm which come supplied with screws size 6mmx60mm. Sold as suitable for masonry, brick, concrete.

I've never done this before. Bit of a novice. I'm guessing at an 8mm masonry bit but that is just a guess. So what is the best sized drill bit? Should the hole be the length of the screw or the length of the plug?

The mirror has steel loops on the back to hang directly off the screws, so that aspect is sorted.

 

[JohnD]

How old is the house and how thick is the wall (measure at a door or window opening). Typically about 9" or 13", plus plaster.

What colour was the dust that came out, and how deep did you drill?

What colour is the drill bit you used? Masonry bits are typically silver, and twist drills (for wood etc) typically black.

Post a pic of the tip if you can.

Are the plasplugs in a block, with a rectangular piece in the middle, with information and holes in it?

Example

Or with a cardboard wrapper like this?

The hole has to be as deep as the plug is long, or the screw, whichever is longer. Disregard the thickness of the plaster, which has no strength. Tap the plug slightly below the surface to reduce cracking of the plaster.

 

[goffy]

Thanks for your reply.

To answer your questions. The house was built in 1978. The wall is 11 inches thick. Brick on the outer but from memory grey dust came out when a tv cable was installed which is why I think its blocks. Just to be clear I have never drilled it. I said I had attempted to screw into it and by that i mean without pre-drilling (like I said I don't have a scooby about this stuff hence the need to join a forum and ask!), I did not go beyond the plaster, just ended up with a bent screw and a damaged driver head. The plugs I ordered have not arrived yet so i've no idea if they will have a drill gauge on them but for the price I doubt it.

 

[JohnD]

Pale grey dust and 1978 suggests lightweight concrete blocks. They are not very strong, but a 50mm steel screw should be adequate.

Breeze has not been used for many years and the dust is blackish.

For a 10mm plug you use a 10mm drill.

Hold it straight and level. If your hole is ragged and the plug is loose, come back for other advice.
If you have a washer that is a loose fit on the drill bit, it will roll downhill if the drill is sloping, but not if it is level.

You can get screws and plugs at places like Screwfix and Toolstation. I habitually use brown plugs and No. 8 screws (4.5mm) which are ample for most DIY jobs.

Example
https://www.screwfix.com/search?search=Plasplugs

 

[foxhole]

Have you tried hammering in a masonry
Nail? What are the mirrors dimensions , weight?

 

[ETAF]

what exactly have you ordered
A DIYer, but put quite a few rawlplugs into all sorts of material over the years , in various houses

i usually buy from screwfix/toolstation, but do buy the decent quality - as i have some really cheap ones before and they have been useless
JohnD has posted some quality ones i would buy

I also now quite like the Bosch multipurpose drills, work great on brick & blocks
https://www.screwfix.com/c/tools/drill-bits/cat12140001?drillbittype=multipurpose

often dont even need to use the hammer function and get a good hole

 

[goffy]

Have you tried hammering in a masonry
Nail? What are the mirrors dimensions , weight?

1mx2m and about an inch deep its very heavy. No I haven't tried hammering in a masonry nail. I figured s nail would just bend.

 

[goffy]

what exactly have you ordered
A DIYer, but put quite a few rawlplugs into all sorts of material over the years , in various houses

i usually buy from screwfix/toolstation, but do buy the decent quality - as i have some really cheap ones before and they have been useless
JohnD has posted some quality ones i would buy

I also now quite like the Bosch multipurpose drills, work great on brick & blocks
https://www.screwfix.com/c/tools/drill-bits/cat12140001?drillbittype=multipurpose

often dont even need to use the hammer function and get a good hole

I ordered these:
https://www.ebay.co.uk/itm/144172643406?var=443472133521

 

[SFK]

For occasional use these drill bits are good.
https://www.screwfix.com/p/dewalt-straight-shank-masonry-drill-bit-set-5-pieces/96162

For precision I tend to start with smallest drill bit and work up in size. (If you try and start hole with largest drill bit the drill bit can wander over the surface before it starts cutting in the wrong place

I gauge the drilled hole depth by marking the length of the screw or Rawl plug (whichever is longest) onto drill bit using masking tape (or sellotape if you do not have masking tape). Add 5mm or so to give some spare length.

When drilling with last drill bit (that matches diameter of Rawl plug) be fast perpendicular in and out so you do not over widen hole. (In softer material I only put final drill bit in 3/4 of depth so fit at bottom of hole is tighter onto Rawl plug).

Double check depth of hole with the screw before putting in Rawl plug (as getting plug out if hole a few mm not deep enough can be difficult).

For heavy items that might pull at the screw I also sometimes drill the hole at a slight angle downwards so leverage of hung item has to overcome this angle as well as friction.

And finally, I presume that your plan is to leave say 15mm of the screw sticking out of the wall for the mirror to hang on??
If this is the case you might have an issue in that the screw is now 15mm too short to expand enough Rawl plug to make it secure. Consider getting some more screws of same diameter that are 15mm longer.

Sfk

 

[goffy]

Thamks for the tips. I was planning to leave the minimum possible amount of screw poking out of the wall. The loops on the back of the mirror only need a few mm poking out as they are only about 1mm thick. I think I'll go and get the plasplugs and screws shown in John Ds post just to be safe.

 

[foxhole]

1mx2m and about an inch deep its very heavy. No I haven't tried hammering in a masonry nail. I figured s nail would just bend.

Masonry nails don’t usually bend .

 

[RandomGrinch]

Having recently put up a very heavy mirror, I can say:

Your screws will have to stick out more than a few mm!
Due to the conical back of the standard screwhead, the loops from the mirror could slip off unless the screw is standing out a bit (it will also make it easier to hang).

...and if your mirror is a semi-permanent fixture, you may want to consider also putting some Gripfill/'No More Nails' on the back - just to make sure it will never fall off (important for us with an adventurous toddler about! ).
Just beware, your mirror/wall may be ruined if you do want to remove it!

....also, you could make a cardboard template of the mirror and tape it to the wall to check your placement - this is far easier than holding a heavy mirror at height, with arms aching, while someone else is shouting 'up a bit', 'left a bit'!

Good luck

 

[blup]

The drill bit will be the size of the plug not the fixing. 5x70mm will be fine and leaves room for the picture wire. Use quality brands like spax reisser, and fischer plugs. Worth considering stainless steel screw for outside.

Blup

 

[freddiemercurystwin]

Thamks for the tips. I was planning to leave the minimum possible amount of screw poking out of the wall. The loops on the back of the mirror only need a few mm poking out as they are only about 1mm thick. I think I'll go and get the plasplugs and screws shown in John Ds post just to be safe.

Is the right answer, a plug/screw combination pack is always a safe bet for the uninitiated.

I don't think anyone's mentioned what type of drill/drill bit you have yet, that might be next .....

 

[ETAF]

i use round headed screws for hanging items like paintings, mirrors etc
infact i hung a picture only Monday using roundhead from my screwbox collection. (another thread on sorting old screws!!!)