Suitable screws and wall plugs?

FreeBear

dhokes said:

FreeBear said:

One tip - Tap the wall plugs in about 12mm below the surface of the plaster. This will ensure the plugs are expanding into something solid rather than plaster. Plaster does not have much strength to it and will crumble. Sometimes, I'll put a squirt of grab adhesive in the hole before inserting the plug.. Or if I really need a strong grip, a resin fix.

How can I tap the wall plug in further btw if the wall plug is a tight fit to the hole + I hammer it in so that its flush to the wall?

I have an assortment of old bolts and short lengths of steel bar for little jobs like this. Or if you want the "proper" tool, https://www.screwfix.com/p/forge-steel-pin-punch-set-8-pieces/936xg

Section62

dhokes said:

stuart45 said:

It might have AAC blocks on the inner skin. Was it really easy to drill into?

It was fairly easy up until around 4cm if I remember correctly and then it was hitting something more solid.

Are you sure you don't have insulation-backed plasterboard (or similar) on the wall?  Otherwise it would be a bit odd to be able to drill in approx 40mm and then hit something harder.  In the old days it was possible bits of stone or similar could find their way into a brick or block, but modern materials tend to be more uniform (e.g. better quality control)  I suppose if you were drilling into a mortar joint there could have been a foreign body included, but unlikely that would happen with both hole positions.

When you say 'internal' wall, do you mean the internal side of an outside wall, or a wall between two rooms.  "Internal wall" in building and construction usually means the latter, the former would be an "inner leaf" if it is a cavity wall.

If it were insulated plasterboard that would probably explain why the plugs didn't hold - there would be very little 'solid' material for them to grip.

Also, is it a house or a flat/apartment?

dhokes

Section62 said:

dhokes said:

stuart45 said:

It might have AAC blocks on the inner skin. Was it really easy to drill into?

It was fairly easy up until around 4cm if I remember correctly and then it was hitting something more solid.

Are you sure you don't have insulation-backed plasterboard (or similar) on the wall?  Otherwise it would be a bit odd to be able to drill in approx 40mm and then hit something harder.  In the old days it was possible bits of stone or similar could find their way into a brick or block, but modern materials tend to be more uniform (e.g. better quality control)  I suppose if you were drilling into a mortar joint there could have been a foreign body included, but unlikely that would happen with both hole positions.

When you say 'internal' wall, do you mean the internal side of an outside wall, or a wall between two rooms.  "Internal wall" in building and construction usually means the latter, the former would be an "inner leaf" if it is a cavity wall.

If it were insulated plasterboard that would probably explain why the plugs didn't hold - there would be very little 'solid' material for them to grip.

Also, is it a house or a flat/apartment?

It’s a house and an internal wall between the hallway and kitchen.

How thick would insulated plasterboard be?

I’ve had no trouble in the past using smaller screws/plugs to attach picture frames.

ThisIsWeird

dhokes said:

It’s a house and an internal wall between the hallway and kitchen.

How thick would insulated plasterboard be?

I’ve had no trouble in the past using smaller screws/plugs to attach picture frames.

You certainly don't appear to have done much 'wrong' - this is going to be a case of 'tweaks', most of which - tighter & deeper holes for the plugs/longer screws - has already been covered.

We need to know what this internal wall is made from. Since it is 'internal', then it would almost certainly be block as you suspect, and 'proper' block at that. What type of drill and bit did you use? And what came out t'hole - whiteish dust followed by greyish?

What does the wall sound like to knock - a bit of 'hollow'? And how easy to drill? I'd suspect a very easy half-inch of plaster or p'board, possibly followed by a half-inch of literally nothing (the drill would step forward with zero resistance) if it's a d&d p'board and you missed the 'dabs', followed by the hard part?

NB: only the 'hard part' will do the holding. 

Type of drill - 'hammer' or SDS? If you have normal concrete blocks, then a hammer is going to struggle.

Anyhoo, you need to ID what you have, and drill to a suitable depth into the solid block layer, and that will be the full depth of a plastic plug plus an extra 10-15mm. And then you choose a screw to match that whole wall depth including the thickness of the board being held, less ~10mm (the screw must not bottom-out in the hole).

The hole should also be a snug fit for the plug, and I usually go a half-mm less than recommended with the drill size, tho' that can sometimes backfire as the hole ends up too tight and the plug buckles as I try and tap it in. (So, extract plug, redrill hole, try again...). The plugs should need a gentle tapping in, tho' not buckle under this force. Then position the screw in it and use this to tap it in further - a few good mm below surface level if it's a plastered solid wall, or right in to flush with the block below if it's d&d'd. The plaster and p'board layers will provide nexttozero strength to something like a coat hanger or safety rail - heavy items subjected to forces.

One more tip - the hole will likely have quite a bit of dust and debris in it after drilling, and this can interfere with the plug being inserted. So I usually use a much longer and larger screw - one that sits nicely in the bare hole - and hand-screw that right in to catch the dust, and pull it out. Repeat a couple of times.

Finally the screw size. You want this to be snug, too, so it bites into the plug and also drives the plug tight against the hole. Again, I usually overdo this, but it's amazing what you can get away with if you lube the screw first. 

A secure fixing will be felt when the screw is nicely firm and resistant as it's driven home - it should 'feel' as if it's well embedded in the plug side, and then stops dead when fully home - you shouldn't feel as tho' it'll keep on turning if you keep going! If it does, then you are most likely Archi-screwing the plug out of the hole!

So, first determine wall construction. :-)

Mr.Generous

In a lot of new builds they double up the plasterboard, quite difficultt to get a fix as cavity wont go deep enough and normal plugs don't hold well into board. Like others said get into the block by pushing deeper. The plugs in your pic are cavity plugs.

Section62

dhokes said:

It’s a house and an internal wall between the hallway and kitchen.

How thick would insulated plasterboard be?

I’ve had no trouble in the past using smaller screws/plugs to attach picture frames.

Ok, if it is an internal wall between two rooms then there would be no sense in them using insulated plasterboard.

For reference though, the standard plasterboard thicknesses are 9.5mm and 12.5mm. Even doubling up the thicker of these would only give you 25mm, plus say 3mm for a skim.  You'd still be 12mm short of your 40mm.  Some of that could be accounted for by a void for dot and dab though.  Insulated plasterboad comes in various overall thicknesses, some as thin as 22mm (overall).

diystarter7

Hi OP

Worth considering as no one else has mentioned this. Have you considered using a backing board?

Thnaks