Lacuna Folding Windows

Folding windows are a unique and exciting way to open up your home to light and life. They are ideal in areas where you want a large opening but do not need access for walking in and out.

MATERIAL OPTIONS

You can choose from several types of wood for your outward-opening folding door: oak, beech, and mahogany. At Lacuna, we use environmentally friendly processes in our wood treatment, making it as low-maintenance as wood/aluminium. Read more about our TMT Composite® treatment below.

TMT COMPOSITE®

TMT Composite® (Thermally Modified Timber) is the term for Lacuna’s advanced heat treatment, which we apply to beech for our folding doors. The process involves no chemicals whatsoever—only heat. After the TMT® treatment, the wood achieves durability class 1, similar to teak, and a moisture content of approximately 5.5%. This makes the modified wood highly suitable for folding doors, where dimensional stability is crucial for a tight, well-functioning product that does not require adjustment in changing weather conditions (humidity/dryness).

TMT Composite® also provides significantly better insulation, as the wood cannot absorb moisture like untreated timber. The result is a folding door built to last for many years.

MAHOGANY AND OAK

FSC-certified sapele mahogany and European oak are also available, oiled in a wide range of color tones without TMT Composite® treatment.

SURFACE TREATMENT OPTIONS

You can choose between several types of surface treatment: painted or oiled. More than 90% of our production is painted TMT beech, and we can paint in any color – including transparent UV protection for TMT Composite®. Our painting process for folding doors is similar to methods used in the automotive industry: 2 coats of primer with intermediate sanding, followed by 2–3 layers of topcoat depending on the color. This results in an exceptionally smooth and durable finish that is stronger than traditional methods used in the window industry.

PAINTED SURFACES

In line with our principles, we use only environmentally friendly, proven durable, and water-based paint products.

You can choose from a wide range of RAL and NCS colors.

For elements that are not particularly exposed, no repainting is required for the first 25–35 years.

OILED SURFACES

For oiled mahogany or oak, we use cold-pressed linseed oil, which protects the wood better than water- or turpentine-based oils.

Oiled products should be treated with oil at least 3 times during the first year to saturate the wood and reduce the risk of shrinkage cracks. After that, maintenance is recommended twice a year, depending on how exposed the element is to the weather.

We also offer a transparent UV surface treatment for sapele mahogany and oak. It functions like a painted finish, meaning the elements do not require surface treatment for the first many years.

COLOR COMBINATIONS

In modern buildings, darker frames and sashes are often used on the exterior. Inside, a lighter color—often white—is typically chosen. We can paint our folding doors in two or three color combinations, including options such as oiled mahogany combined with a white finish.

We can also apply various textured finishes as well as a clear coating, similar to a lacquer.

DIMENSIONS AND OPENING

Lacuna’s outward-opening folding windows are made to measure, from 1.5 m up to 6 m in width and with a maximum height of 2.8 m. The individual door panels can be up to 100 cm wide. Lacuna folding doors are available in configurations with 3 to 9 panels and offer many different options for the placement of the access door. For renovation and conversion projects, it is important to ensure that the building’s structure is designed for—or can be adapted to—the chosen solution.

MILLIMETER PRECISION

All processing is carried out using CNC robots with a precision of one-tenth of a millimeter.

Our quality control systems and CNC robots eliminate the risk of human error and excessive tolerances.

OUTWARD-OPENING OR INWARD-OPENING FOLDING WINDOW

The opening of Lacuna’s outward-opening folding doors is spacious and tailored to each individual project. We are able to customize our doors to match other types of windows and doors in your home.

There are endless possibilities and combinations in terms of width, height, frame type, interior and exterior colors, glass type, handle design, and much more. All in all… you’ll always get a folding door that perfectly matches the look you want.

NUMBER OF PANELS AND PLACEMENT OF THE OPENING POINT

There are many options and combinations when it comes to the number of panels and the placement of the opening point. To allow the window to fold, an odd number of panels is required. This means that a window with an odd number of panels will fold with all panels stacking to one side. If the window consists of an even number of panels, they will be split so that an equal number of panels open to each side.

Below are a few selected examples of opening options for different numbers of window panels.

GLASS

Glass makes up a large part of an outward-opening folding door, which is why choosing the right type is essential. In addition to double or triple glazing, our folding doors can be supplied with glass solutions that meet a variety of requirements and functions. We use only high-quality glass from leading manufacturers of building glass solutions, and we offer a wide selection with expert guidance. Please note that the more energy-efficient glass you choose, the greater your contribution to the environment. Investing in the most energy-efficient option pays off, as both the door and the glass are built to last for many years.

GLASS OPTIONS

Most of our folding doors are supplied as façade folding doors, typically fitted with double or triple glazing using energy-efficient glass. However, our doors can also be delivered with a wide range of other glass options:

Low-energy glass
Sound-reducing glass
Safety glass (toughened and/or laminated)
Solar control glass
Self-cleaning glass
Frosted glass types
Glass with integrated blinds, and more

INTERNAL GLAZING BEADS

Unlike most other door and window manufacturers, the glass in a Lacuna folding door is installed from the inside. This means the glazing beads are securely positioned on the interior, providing several advantages. Reduced maintenance, as there are no external joints. Increased security, as the glazing beads cannot be removed from the outside.

DESIGN DETAILS

Lacuna offers great flexibility in design, allowing you to choose freely whether you want your folding doors with or without glazing bars, with Helima bars, standard glazing bars, solid panels, or perhaps with transoms. You can choose from several glazing bar widths: 20 mm, 25 mm, 36 mm, and 42 mm, with different profile options. In addition, horizontal transoms are available in 55 mm, 75 mm, and 110 mm.

FOLDING WINDOWS
GLAZING BARS

Lacuna manufactures several different types of glazing bars and mullions. Most of our customers choose 25 mm palace glazing bars with what we also refer to as a farmhouse profile on the interior side. This design is also available in widths of 20, 36, and 42 mm. For all widths, an interior softline profile is also available, offering a simple and modern look that matches the style of new-build homes.

All of our glazing bars are mortised into the outer frame (not bonded onto the glass) and therefore cannot fall off.

HELIMA
GLAZING BARS

As an alternative to traditional glazing bars, we also offer Helima glazing bars. These are integrated between the panes of glass, meaning there are no bars on either the exterior or interior of the door. Helima is a cost-effective option and offers a significant advantage when it comes to cleaning. The bars are available in several widths: 18, 26, and 45 mm.

GLAZING BAR SOLUTIONS

See glazing bar profiles, dimensions, and sizes below.

TRANSOMS /
HORIZONTAL MULLIONS

If wider glazing bars or mullions are desired, we also offer horizontal transoms in 55 mm, 75 mm, and 110 mm. These are continuous and therefore divide the glass within the door. The transoms are, of course, fully integrated into the frame design.

PANELS

Lacuna also offers panels, including flat and framed panel options. The panels are not solid but are laminated with highly insulating material to ensure optimal insulation. Panels are supplied in the same color as the rest of the door.

TOP-HUNG WINDOW

You have the option to integrate a top-hung window into one of the panels of your folding door. This is most often used in spaces where there are no standard windows, or where ventilation would otherwise be added through vents in a window or door frame. Ventilation vents create a significant thermal bridge and will never remain fully airtight over time.

MADE FROM ACID-RESISTANT STAINLESS STEEL

Why choose Lacuna?

When quality needs to be felt

Read why customers choose Lacuna for their homes and building projects.

“Lacuna doors are top quality. Quite simply, Lacuna was recommended by Paw, our architectural advisor from We Make Space, and after looking at various folding doors, there was no doubt. Lacuna was by far the most beautiful and the best quality. We bought and had a three-panel door installed by Hardy from Dansk Vinduesservice ApS. Professional and excellent advice, and the installation was spot on. We felt in safe hands all the way through. We’re looking forward to a summer with our folding door wide open.”

Lars Blomstrøm

“We have just had a Lacuna folding door with four sections and a double door delivered. The guidance we received before ordering was excellent. Once the doors were ready, we were able to have them delivered on the day that suited us, and since we were not quite ready for installation, they stored the doors for us until we needed them. The doors arrived as planned, and the carpenter was very impressed by how clear the assembly instructions were, as well as by the quality of the materials. They are very beautiful and sturdy doors. They glide extremely well, and the service has been absolutely top-notch. I can only recommend spending a little extra money to get doors of the very best quality — doors that we know will last.”

Louise Pedersen

“Lacuna has delivered the most beautiful folding doors for our new bedroom. Our expectations were sky-high and were truly exceeded – we received the best service from start to finish, and every single day we’re so happy that we can open up and bring nature inside. Thank you, Henrik and the entire Lacuna team!”

Lone

“From the very first phone call until now, we have received the very best service. We were given really great advice on which door to choose in order to get the most out of the room it was going to be installed in. We also chose to use the company Lacuna works with for measuring, and we are so pleased that we did. They have also been a great help with everything we needed. We can therefore only recommend buying from them again. Thank you so much for all your help. We look forward to replacing the other doors in the house as well, and we know that you will be there ready to help.”

Katja Schibsbye

HAVE A LOOK AT OUR SHOWROOM

We know that visiting Denmark isn’t possible for everyone, so we’ve created a short video to give you a quick visual tour of our showroom and show Lacuna’s folding doors in action. It’s an easy way to experience the product and feel more confident in making the right decision.