External and internal windows

External and internal windows

Metal external window sills – What to choose – steel or aluminum?

The window sill has to cover the wall before covering it. Its basic function therefore imposes a material that is durable and easy to maintain. For these reasons, steel and aluminum are used for the production of window sills as one of the most common materials.


Enjoying unflagging popularity for many years, external steel window sills can survive for many years to fulfill their function and enjoy the eye. However, in order to be long-lived one needs to remember about a few basic rules for their assembly, which will be discussed later in the text. Then the window sill will fulfill its basic role, which is drainage of rainwater.


The steel window sill should be mounted so that its side edges are not under the plaster. Under the influence of temperature, the steel works by changing its dimensions, therefore the place of contact of the steel sill with the wall should be secured and sealed with plastic material. It will also be necessary to use blinds on the edges of the window sill. Blinds should be chosen so that they correspond not only to the color of the material from which the window sill is made, but also to match the profile of the window sill. Unprotected ends could corrode.


The steel window sill can also be secured with an additional foil that facilitates maintenance and protects against external factors. If, however, we want the sill to refer to its color to the window frame, then a steel veneered window sill can be used. It is durable, does not require maintenance, and the window sills adds elegance and gives a classic look.


The assembly of an aluminum window sill requires a larger budget, but it is a price that is worth paying for the benefits of this solution. Due to its physicochemical properties, aluminum is characterized by high durability and stiffness. The use of aluminum on external window sills means that the window sill is practically maintenance-free, even in adverse weather conditions.


An alternative to the aluminum window sill are tile type aluminum window sills. Forming a window sill in the form of a clinker tile gives the effect very similar visually to the latter material, while at the same time relieving the budget. The effect of timeless elegance is not achieved at the expense of durability and resistance to external factors. Aluminum tile window sills perfectly match both PVC, aluminum and wooden windows.

To obtain an additional effect affecting both the elegance and durability of window sills, anodizing aluminum window sills can be used, thus giving the material a precious metal glow.


When mounting, remember that the width of the window sill is large enough to protrude a minimum of 5 cm beyond the facade of the building. In this way, rainwater will not unnecessarily wash the façade. An important element of the window sill is the so-called drip – this is an incision in the bottom part of the window sill, which prevents the rainwater from leaking from the bottom of the window sill and, as a result, the walls are being drenched. The slope of the window sill of the order of 5-10 ° to the outside will provide a natural gravitational fall of the rainwater from the window sill. The window sill can not cover the drainage holes in the bottom part of the window frame. This is especially important for PVC and aluminum windows.

When making a choice between window sills made of steel and aluminum window sills, we have to take into account, apart from the budget, two variables due to the characteristics of the materials: resistance to external factors and ease of cleaning. From the wide range of external window sills found in our offer, everyone will find something for themselves!