Mount aluminum windowsill

An aluminum sill is usually mounted outside. Unlike other materials, it is bolted to the lower window frame. In addition to thermal insulation and sound insulation is required. Aluminum sills must not come into contact with some other materials.

Discharge, tilt and sensitivity

A window sill made of aluminum usually has a preformed profile with attachment and drip edge. Matching there are attachable side tails. The depth of the windowsill, also known as the projection, must be chosen so that the drip edge protrudes at least three centimeters beyond the facade. The angle of inclination must be at least five degrees, which corresponds to about ten percent of the radius.

A special feature of Alu is the relatively high expansion in heat, which require a corresponding expansion joint. If installed too close, cleaning cracks or bulges may occur. Aluminum reacts sensitively to copper or copper-containing metals and alloys. In addition, lime and cement can damage the aluminum, which is why the mounting should always be carried out after the completion of masonry and plaster work.

How to mount the aluminum windowsill

  • Stainless screws
  • Schraubenabdeckkappen
  • Eventually expansion dowel
  • Antidröhnstreifen or mat
  • sealing tape
  • Tails
  • screwdriver
  • spirit level
  • drilling machine
  • drill

1. Drill mounting holes

Hold the aluminum sill to the lower window frame and mark the pre-cut holes on the window frame. Drill accordingly screw size. If necessary, dowel the holes with expansion dowels.

2. Attach end pieces

Attach the expansion compensating band in the end pieces. Insert the two end pieces onto the windowsill sides according to the manufacturer's instructions.

3. Soundproofing

Stick the anti-drip strip or mat to the underside of the projection so that about two-thirds of the surface is centered.

4. Screw

Insert the sill on the parapet and screw the screw-on support to the window frame after you have inserted a sealing strip. Cover the screw heads with caps.

5. Eventually post-jointing

If lateral joints occur after assembly, you can re-joint them with silicone or polyurethane foam. Make sure that no grout will overflow the end pieces.

Tips & Tricks

Buy your aluminum windowsill with a glued-on protective foil. Only remove the protective foil on the projection when you have finished assembling.

Video Board: How to cover a window sill