The type of building material, whether hard or soft, massive or hollow block, will be determined at the very latest, when drilling the hole for the fixing.

If the building material of the wall is unknown, rotary drilling should be used at first. Impact should only be switched on, if no progress is being made. In the case of perforated bricks, there is a risk of the webs breaking away with impact drilling. 

If the drill goes in with rotary drilling „like butter“, it can be assumed that the building material is soft. If it suddenly slips into nothing and then meets with resistance again, it is fairly sure that perforated building materials are concerned. 

Analysing the drill dust provides further clues: if it is red, then it is probably clay brick. White dust points to sand-lime brick, whereas grey can be assumed to be concrete.

A hammer drill is the best choice for drilling in concrete as it works with considerably higher impact energy (Fig. 1 to 3).

Drill the fixing hole exactly at a right angle to the masonry and always a little deeper than necessary. 10 mm safety reserve is recommended – in the case of drill dust remaining in the fixing hole, in spite of careful cleaning.

 
 
Rotary drilling is suitable for building materials with a porous structure and panels. The spiral blade of the drill is sufficient to remove the material.
   
 
 
Building materials with a compressed structure are drilled with impact. The drill is propelled forwards by many light impacts.
   
 
 

The hammer drill functions with less, but at the same time, considerably stronger impacts for concrete.

   

Drill perpendicular to the masonry and do not change direction. In concrete and solid masonry, (solid brick) use impact or hammer drilling.  The difference lies in the impact intensity. In hollow masonry, soft, lightweight masonry, and wall panels drill without impact, so that the drill holes will not become too big, or the webs in the building material break away.

Removing drill dust.
Fixing Ø = drill hole Ø for plastic plugs.  Drilled holes, which have turned out too big, can also cause the fixing to turn as the screw is fastened, and a hold is hardly achieved.

Minimum drill hole depth = fixing length + 10 mm reserve,
for flush fixing (standard fixings).
Minimum drill hole depth = anchorage depth + maximum bearing thickness + 10 mm reserve
for push-through installation (long fixings).