For 20 years we have been specializing in the production of wooden windows and exterior doors. We are of ideal size to successfully implement both complex projects and provide exceptional attention and care to each of our individual clients.
We produce according to individual orders for both individuals and companies. We can provide and implement classic and non-standard solutions for timber windows and doors and we already count thousands of happy customers in Lithuania and the United Kingdom.
Even before the signing of the contract, we provide free consultations about products, their use and maintenance, submit pre-project proposals, provide the necessary technical information. We offer you professional and prompt service, ensure the highest quality of products and provide guarantees.
We offer you a professional and responsive service, the highest quality products and guarantees.
Fenestrum is a Lithuanian manufacturer of wooden windows and exterior doors with over 25 years of experience. We manufacture Euro standard windows for Lithuanian and European markets, Sash and Casement windows for the British heritage market, PSK and HS terrace systems, and external doors.
For sale directly from the factory – no intermediaries, which keeps the price competitive. Each product is prepared by hand: sanded, primed, sealed, and painted, then finished with a protective layer.
We produce four main product groups:
Wooden Euro windows (78 mm and 100 mm profiles) – for private homes and commercial buildings in Lithuania and Europe. Sash box and sash spring windows – authentic British-style sliding sash windows for heritage and conservation properties in the UK. Terrace systems PSK and HS – large-format sliding doors and windows. Exterior doors – classic and modern.
We also offer aluminium cladding, window sills and edge trims.
Fenestrum wooden windows are made from high quality Nordic pine, Maple</ (meranti and mahogany). We also produce from Oak and maumedžio, and for special projects, we can select exotic woods – such as Accoya, teak or sapele.
Smoked wood can be of two types: digested (glued in layers from individual blanks – most stable, resistant to deformation) or unloved (stabilised, with extended wood layers – more natural texture). Both types are premium selected glued timber beams, with cross-layer arrangement – this ensures that the window will not crack or warp even during significant temperature changes.
The choice of wood usually depends on the client's budget and the architectural style of the building – wood does not change the U-value or airtightness properties.
Euro profiles windows comply A, A+ and A++ energy efficiency classes. The 78 mm profile achieves A-class ratings (thermal transmittance coefficient of around 1 W/m²K), and the 100 mm profile achieves A+ and A++ classes (0.75–0.85 W/m²K).
Windows are equipped with two (in the 78 mm model) or three (in the 100 mm model) sealing strips. Glazing units are 2 or 3 pane, with selective coatings and a warm TGI spacer, achieving Uw up to 0.5 W/m²K.
We use German Roto Frank AG Boilers – reliable, long-lasting and recognised throughout Europe.
You can choose different security levels: Standard, RC1/RC1N, RC2/RC2N or RC3 – according to the building's purpose and the client's needs. A higher level of security is recommended for ground-floor windows accessible from the outside or for properties requiring additional protection against intrusion.
The usual production time is 8–12 weeks from order confirmation to delivery. The timeframe depends on the season, order volume, and project complexity.
For large or particularly complex projects, the timeframe may be longer. During peak season (spring and summer), we recommend planning orders in advance. We will confirm the specific timeframe along with the quote.
Euro locks and doors provided 5-year warranty on the product and 2-year warranty on fittings.
Sash and casement windows for the British market come with an extended warranty: 25 years for timber against rot and insect infestation, 10 years for workmanship, 10 years for white paint finishes, 8 years for glass units, 5 years for stained finishes, and 2 years for seals.
Yes. We make both classic British types: Sash Box (with pulleys and levers, hidden inside a box within the frame) and Sash Spring (with coil springs, narrower frame profile).
The windows precisely match Georgian, Victorian, and Edwardian profiles – horn details, glazing bars, parting beads, and meeting rails. We work from measurement drawings or original window templates, so we can also reproduce versions that meet the requirements for conservation areas and Grade II listed buildings.
Yes. We have More than 20 years of experience in the British heritage market We manufacture Sash Box and Sash Spring windows that comply with the conservation requirements of London boroughs.
We can provide drawings, specifications, and paint samples suitable for inclusion with a Planning Permission or Listed Building Consent application. Where necessary, we produce single-glazed windows with a traditional putty-glazed look – as required by the strictest conservation areas.
Aluminium cladding is an external aluminium shell that covers a wooden window profile from the outside. The wood remains on the inside (natural feel, warmth, aesthetics), while the aluminium on the outside protects against moisture, UV rays, and temperature changes.
Because of this reduced maintenance requirements – you don't need to repaint windows from the outside so often. Aluminium is also available in all RAL colours, so the exterior can differ from the interior colour. We recommend this for where windows are very exposed to the weather or the building is by the sea, forest, or in open areas.
Yes. We manufacture two types of large-format sliding systems: PSK (Parallel Sliding and Kipp) – where the sash opens parallel and slides to the side, and HS (Hebe-Schiebe, known in English as Lift-and-Slide) – intended for the largest terrace openings, where the sash is lifted and slides to the side.
Our systems are perfectly suited for modern private homes with a view of a large garden or terrace. We ensure thermal insulation, airtightness, and safety measures.
Painting Teknos paints Choosing the full RAL colour palette – it is one of the most reliable paint systems for wood products in Europe. You can choose between opaque paints or Tekna A system that allows the natural wood grain to be seen through the colour.
The painting is carried out at the factory in several layers – primer, intermediate layer and topcoat. The windows arrive at the customer's fully prepared: painted, glazed, only requiring installation.
In Lithuania, we offer consultations, measurements and installation services according to the client's needs. In the United Kingdom, we most often work through installation partners, architects, construction companies or directly with owners who organise the installation themselves.
Delivering throughout Europe and the United Kingdom. We package products carefully to prevent damage during transport. We arrange precise delivery terms in advance.
You can contact us by phone, email or video call. For larger projects, we organise meetings in the UK or invite you to visit our factory in Lithuania, Jonava district, where you will be met by the production manager or company founder.
For a more precise quotation, please provide: product name, dimensions, quantity, thermal class, and other important information. Before any contract is signed, we offer free consultations, preliminary proposals, and the necessary technical information.
