Tiling over Tiles

pablogilbertsqr · 27-11-2007

Hi Buddies
I am a new member to this forum and at this present moment time live in Spain.
It seems to be normal practice here to tile on tile, i am a little behind with things as it has been many years since i have worked, but what are your views on this and what about the prep plus cement?

**Dan** · 27-11-2007

You can tile over tile, infact as it is so flat it can be one of the best surfces to tile onto.

You need to ensure the existing tiles are fixed well though, and in a wall situation you need to ensure the weight of the new tiles plus the old tiles are not too heavy for the wall / substrate. So a plastered wall with tiles on already may mean your new tiles would go over that weigt.

Plaster can carry 20KG per square meter, plasterboard can carry 32KG.

In a floor situation it's usually height issues more so than weight but always check that the tiles are fixed well enough.

Generally pulling them off is a safe bet but time consuming and usually results in needing to make good here and there at best and re-plasterboard / plaster at worst.
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Some existing topics on this subject:-

pablogilbertsqr · 27-11-2007

Hay Dan
Thanks Buddy for your help with that, just a quick Question Whats an SDS Drill?

**Dave** · 27-11-2007

hi pablo....

SDS Hammer / Chisel Drills
What is it?

The SDS drill is a drill with an enhanced hammer action that when compared to a conventiona hammer drill is able to deliver hundreds of times the energy per hammer blow. To go with this it also has a different chuck design and special SDS drill bits to eliminate the possibility of bit slip, and also to withstand the force of its hammer action.
What difference does it make?

When drilling hard masonry or engineering bricks the difference is astonishing. Where an ordinary hammer drill may take minutes to make even a shallow hole, the SDS will pound through it in seconds. For this reason you also need to take it easy when drilling right through things like walls, because as you break through you can end up removing a large chunk of wall when the drill hammers its way out. If possible, always drill inwards from both sides to avoid this.
Operating modes

SDS drills operate in 3 modes:
Drill only

Like an ordinary drill, but maximum speed tends to be slower (under 1500 RPM) and torque higher.
Drill and hammer

The above mentioned enhanced hammer drill action. In spite of the extra performance, SDS drills also tend to be somewhat quieter than the conventional hammer drill.
Hammer only, no rotation

Not all models have this (sometimes the ones that do are called SDS+ drills). It greatly expands the range of tasks you can do. In this mode the bit is not rotated at all. Hence you can fit special SDS chisel bits and use the drill like a mini Kango or concrete breaker. Ideal for chasing cable runs or socket cut outs in walls, removing tiles, and light demolition.
What to look for

Safety clutch: Because the SDS chuck eliminates the possibility of the bit slipping, there is the problem of what happens if the bit should jam in the work. The mid range or better tools include a safety clutch that releases should this happen. Without a safety clutch you run a very real risk of being injured by the drill body, as it spins out of your grip. Broken wrists, or being thrown off a ladder are not unheard of results in these cases.
Sensible weight: i.e. 2kg not 5kg. Many of the budget tools are heavy. This is fine for demolition, but not so good for prolonged working.
Chisel position lock, for use in hammer mode: Many budget drills disengage the rotation of the bit, but leave it free to turn. You will not be able to chisel a nice straight chase in a wall with a freely rotating chisel. Better drills will lock the bit in one position, and the best will allow it to be locked in any user selected position.
Some budget tools will often require frequent lubrication with grease. After a while this will begin to ooze from various places and tend to get spattered about, which is not so good for keeping either the work piece or the operator clean!
SDS downsides

SDS drill bits can be more expensive than conventional masonry bits (although usually last much longer).
You cannot put ordinary bits in an SDS chuck unless you fit a adapter chuck first. These typically extend the length of the drill further, and also do not allow use of the hammer mode. (Some SDS drills come with a replacement chuck for ordinary bits to circumvent this problem)
Even professional light-weight drills tend to be a few inches longer than a conventional hammer drill. This can make them more awkward to use in confined spaces.