Walls are crumbling while I'm trying to put shelves up

[vetinry]

Hello

I am usually pretty competent with DIY.
However, we've just moved into our new office and I am having a nightmare putting some shelves up. The walls have been replastered and this is over a blockwork wall.
I duly drilled the holes and ensured that the wall plugs were knocked through the plaster into the blocks behind. But the screws are simply not tightening and I fear that the blocks are just crumbling around them.

At first I thought it might be the cheap wall plugs I was using but I've just tried with Rawl Plug UNOs and still the same effect.

Now the wall is beginning to look a bit of a mess - I'd really rather not move the holes and start again because the shelf brackets largely cover the bits of plaster that have come off.

Can anyone suggest best course of action

Thanks

Steve

 

[PrenticeBoyofDerry]

In what way were they re-plastered?
Was it a skim over or were the walls back to bare brick/block?
Is there a possibility that the walls are plasterboarded and the plugs are turning within the void behind the board rather than the brick/block work?
If so longer drill hole in to wall behind and longer plugs.
If the wall is a stud wall then hollow wall anchors could well be a good fixing to use.

 

[vetinry]

Thanks for the reply

They were skimmed over and I think there was a small void behind the plasterboard.

But I did knock the plugs all the way through (or so I thought) the void and they seemed to go tight so I assumed I was in the substrate behind the plasterboard.

I've managed to get the plugs out (only one support tried so far) and I've checked that the holes are deep enough, cleared them out as best I can, filled them with hard as nails and tapped a fresh plug in as far as it will go.

Going to leave it for a couple of days and then try again.

Hopefully this might work?

Steve

 

[foxhole]

http://www.plasplugs.co.uk/fixings-thermal-block.html if you have thermalite blockwork or you can use a plugless screw like this
http://www.screwfix.com/p/masonry-phillips-head-screws-5-3-x-70mm-pack-of-100/18064 but don't pilot, screw straight in, the longer the better.

 

[vetinry]

That's great

If the hard as nails doesn't work, I'll probably try carefully drilling out and trying these instead.

Should the plasplugs still be poked through the plaster wall and void onto the block surface

Thanks

Steve

 

[foxhole]

Depends on the depth of void and length of plug, you can leave flush with surface if you can get at least 30-40mm of plug in the blockwork.Also depends on style of shelving, if you fix thru plasterboard without support it may distort the plasterboard in which case a spacer may help, an off cut of copper or ali pipe is one easy solution.