Shelves and concrete
I am trying to put up a wooden shelving unit which will hold a medium weight but I am having
alot of trouble attaching it to the wall. I have tried wall plugs of all descriptions and then screwing the unit
to the wall put I think the wall is not brick but soft concrete. As I drill the hole for the plug a grey dust comes
out with it. Do you have any suggestions how I can attach the unit to the wall???
You just need the right plugs. The grey dust is the cement that the drill bit is drilling away so yes you will
get dust when drilling through anything. The grey just means plaster or cement. There are special cement/mortar
plugs, so ask for them. They are called masonry plugs and often come with the screw also.
Efflorescence removal
Our company has about 12,000 ground and polished decorative block
that has two coats of a 20% solid sealer on them. The problem is there are areas of efflorescence bleeding through. How do we remove it?
Efflorescence is caused by the salts in the block leaching to the surface this usually happens in areas of high humidity. It can be removed by washing with either a strong detergent or muriatic acid such as sure klean or similar product. But if you don't find the source of the moisture can and most often will reoccur.