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Lacuna A/S, which is a Danish company located in the small town of Langeskov on Funen in Denmark, specialises in the design and manufacture of high-end timber bi-fold doors. It was founded in 2008 by Henrik Brunsø, who at the time was renovating his house and needed a new bi-fold door.

His wishes for this door were quite simple. The door just needed to be sustainably and well made (and from good materials naturally), well insulating and airtight and have low maintenance requirements. Yes and then of course it needed to have an appearance which would fit well into his Danish designed home.
However... having extensively researched both the Danish and European market, he had to come to the conclusion that there was no such bi-fold doors on offer...

So what did he do?... He sat down with his old friend Lars and with their combined knowledge and expertise of timber, joinery, design and engineering they created the first Lacuna bi-fold door... and the rest is histor...

 

The frames of Lacuna doors are manufactured in FSC timber and include the options of heat treated beech, oak or mahogany. Threshold are made of mahogany. All frames are laminated to ensure strength and stability.

Please see below description of each type of timber with their characteristics and a short summary of maintenance requirements.

For more detailed information regarding maintenance please see below link

MAINTENANCE

Bifold doors

HEAT TREATED BEECH

  • Beech sourced from sustainable forests in Germany
  • Heat treated and therefore a very stable material (durability equal to teak – cl. 1)
  • Paint finish silky smooth and with no show of wood grains
  • If gloss finish is chosen it resembles powder coated aluminium
  • Total u-value typically between 0.95mk and 1.17m²K
  • Minimal maintenance requirements with typically no need for repainting the first 20-30 years

HEAT TREATED BEECH

 

Bifold doors

OAK

  • Sourced from sustainable forests in Germany
  • A naturally look with a clear finish showing off the quality of the oak structure
  • Treated with special u-v filter oil, preventing the wood from fading in the sun
  • Total u-value typically 1.15 – 1.35 W/m²K
  • Regular maintenance required in form of application of oil at least once a year

 

Bifold doors

MAHOGANY

  • Sourced from a controlled Danish owned forest in Congo
  • An oil-rich tropical hardwood with a beautiful reddish hue
  • A clear finish showing off the structure of the wood
  • Treated with special u-v filter oil, preventing the wood from fading in the sun
  • Total u-value typically 1.15 – 1.35 W/m²K
  • Regular maintenance required in form of application of oil at least once a year.
Door dims

DIMENSIONS

The Lacuna folding door is manufactured to individual measurements with a width of up to 6m and a height of up to 2.7m.

The max width of the panels are set at 800mm for triple glazing and 850mm for double glazing. The reasons for these width (weight) restrictions are as follows:

  1. Larger (heavier) doors can be be difficult to handle and if for example a child or elderly person was caught up in a larger door in a gale, they could get injured.
  2. Lacuna likes to be sure that their doors can last for 50 or more years. However, if using very heavy panels, the strain on the hinges (in spite of being made from 5mm marine graded steel) may in the long term potentially compromise the functionality of the doors.
Inwards outwards

PANELS

For all types of Lacuna bi-fold doors, there is a choice between outward and inward folding. We usually recommend outward going doors in exposed areas, as this gives 100% water tightness at the threshold.

All folding doors have one master door, which can work independently of the other doors should this be required. The master door can either be the single panel attached to the side frame or the last one in a sequence of folding panels. The possible master doors are indicated with an orange M in the gallery below.

The different configurations depend on the number of panels, and all works in odd numbers. For examples of configurations see our Library page.

 

3a 2 3b 12 4a 11 4b 11 5a 11 5b 11 6a 11 6b 11 6c 11 7a 11 7b 11 8a 11 8b 11 8c 11 8d 11

Below is a list of section drawings (standard options) and manuals for the Lacuna bi-fold doors. If you need additional technical information for your project please do get in touch and we will be happy to help. Drawings are available in both CAD and PDF format.

When it comes to installation, we always recommend that the builder or installer takes the time to watch our short video, which in details shows the process of installing a Lacuna bi-fold door. A written manual also comes with the doors at delivery (listed below too). It is important that the guidance in these documents are studied carefully on beforehand in order for the installation to be carried out successfully.

Apart from showing the installation method, the installation video gives a good impression of the quality, functionality and appearance of the Lacuna bi-fold doors.

Technical

SECTIONS

TOP FRAME AND THRESHOLD

SIDE FRAMES

INSTALLATION

MANUAL (TEXT)

MANUAL (VIDEO)

MAINTENANCE

MANUAL

With internally beaded glazing (fixed with butylene sealant), toughened / laminated glazing as standard, double rebate in frame, locks by Ruko/Assa on main door with 3-point locking system, 6-lever locks used as standard (and available in different configurations), 5.5mm marine grade stainless-steel (316) hinges with security pins, hinges kept together by a bolt (which cannot be dismounted at the top) and all secondary door-blades being locked individually into both the top frame and the threshold – the Lacuna bi-fold doors are burglar-proof to the highest degree.

The Lacuna bi-fold doors have been tested at the Danish Technological Institute and have passed very stringent security tests. As part of the tests a 15 kg ‘cannon ball’ in an 11 meter long chain had to continuously swing into the glazing. (See photo below).

SECURITY TESTING

 

 

Security
  • Tested to EN1627-30 / PAS24
  • Internally beaded glazing (fixed with butylene sealant)
  • Toughened and laminated glazing
  • Double rebate in frame
  • Locks by Ruko/Assa on main door with 3-point locking system
  • 6-lever locks used as standard
  • 5.5mm marine grade stainless-steel (316) hinges with security pins, hinges kept together by a bolt (which cannot be dismounted at the top)
  • All secondary door-blades being locked individually into both the top frame and the threshold
RUKO / ASSA

Lacunas bi-fold doors come with either double or triple glazing, which usually have a total u-value of between 0.95 and 1.15 W/m²K.

Lacuna uses glass from Saint Gobain, who is a world leader in the glass industry. As well as the standard clear toughened and laminated glass Lacuna doors can also be manufactured with soundproofing glass, solar control glass and opaque glass (decor and interior glass). For the full range, please visit Saint Gobain’s website.

GlazingGLAZING BARS

As an optional extra Lacuna bi-fold doors can be supplied with glazing bars in widths of 25mm or 42mm and transoms and mullions in widths of 55mm or 85mm. The vast majority of Lacuna’s customers choose the energy-efficient 25mm mansion squares.

All Lacuna’s 25mm and 42mm glazing bars are tenoned (not attached to the glass) and thus cannot fall off.

The glazing bars are supplied as either classic profile or soft line profile.

Please ask us for more details if glazing bars is required

All Lacuna’s ironmongery is Danish designed with a typical ‘less is more’ Scandinavian style. The simple and crisp design adheres to the strict principle of 18mm diameter. This goes for handles, hinges, top rollers and bottom wheels.

Handles

To prevent rusting in harsh seafront locations Lacuna, uses as a standard, marine-grade materials for all the elements including handles, hinges, screws and strike plates.

Handles Handles

All secondary panels on the bi-fold door sets have a handle which locks the individual panel upwards into the top frame and downwards into the threshold. The master door has a lock (from Ruko/Assa) and two manual locks at the top and the bottom.

Handles SAT-8519

For projects with swimming pool areas with chlorine filled air, Lacuna is also able to offer suitable bi-fold door solutions. Please ask for further information regarding this.