Internal and external windowsills are small but important part of every house. External sills help to save the façade of the house while internal sills are important to reach the integrity in the design. High quality, durable sills that matches the timber windows, floor, or wall colours will add more cosiness to both private and public spaces.




Fenestrum makes internal sills using multilayer timber processing technology. It ensures the highest level of durability and allows to have a stable form of a sill. The sills can be made from pine, meranti, oak, redwood, or any other wanted timber.


There is huge variety of colours the sills can be coated.

  • Colours from RAL pallet.
  • Natural transparent varnish to see the natural colour and texture of the timber.
  • A big variety of mordants which allows not only to see natural texture of the timber but also to have it in preferred tone.


The internal sills can be made in any measurements.


Fenestrum uses only Teknos coatings for its timber products.


While affected by direct sunlight any timber can change its colour. Intense moisture or temperature level changes can be a reason of cracks in timber or its deformation. The internal sills should be well maintained if seeking longevity. Depending on how often the sills have mechanic impact and how much direct sunlight receive the surface of sills could be renewed by sanding, putting new layer of varnish or paint.


The clients should carefully choose the coating because it will help to keep the looks of the sill. If sills will be affected by direct sunlight Fenestrum offers not to choose transparent varnish or even mordant. Even though the latter is better choice than a transparent varnish, because of direct sun heat the surface of the sill can became dark, the timber can extract the resin. If the surface will be affected by direct sunlight dark colours from RAL pallet are also not recommended.


The sills should be cleaned with wet wipes without any abrasives and avoid using lots of water.



As the external sills are outside, they are made from galvanised tin-plates. These sills are important not only as a part of exterior but also are necessary element to finish the facade and to protect it from rain, snow etc. The external sills can be painted in all RAL colours. Most often the colours of external sills match the colour of the roof or rain pipes.