Lacuna

Lacuna Folding Door

A bespoke Danish timber bifold-door system for projects that need a genuinely wide opening together with strong airtightness, insulation and long-term dimensional stability.

Up to 90%Clear opening

From 0.8 W/m²KUw with standard triple glazing

Up to 6 × 2.8 mMade-to-measure size

3–9Door panels

A wide opening without giving up year-round comfort

Lacuna folding doors are made to measure in inward- or outward-opening configurations and can open up to 90% of the aperture. The top-hung system keeps the running mechanism out of the threshold and uses an integrated track within the head frame for accurate installation and smooth operation.

Timber engineered for stability

Painted doors are principally made from FSC-certified, heat-treated beech. Lacuna’s TMT Composite® process uses heat rather than chemicals to achieve durability class 1 and low moisture uptake. Sapele mahogany and European oak are also available for selected oiled specifications.

Features and performance

Inward- and outward-opening configurations
Made-to-measure widths from 1.5 m to 6 m
Maximum published height of 2.8 m
Individual panels up to 1 m wide
Double sealing in the frame and triple sealing between panels
Top-hung operation with an integrated running track
FSC-certified heat-treated beech, oak or sapele mahogany options
Double or triple glazing with acoustic, safety and solar-control options
Each panel locks in place with internally retained glazing

Technical specifications

Overall width1.5–6 m

Maximum height2.8 m

Maximum panel width1 m

Panel count3–9 panels

Clear openingUp to 90%

Uw with comparable double glazingApproximately 1.05 W/m²K

Uw with standard triple glazingAs low as 0.8 W/m²K

Published operating range–60°C to +50°C

TMT beech durabilityDurability class 1

ConstructionAll panels locked; internal glazing beads

Colours and finishes

Painted, oiled, or both.

Most Lacuna doors are painted TMT Composite® heat-treated beech, in any RAL or NCS colour. FSC® certified sapele mahogany and European oak are oiled instead, and finishes can be combined on one door.

Painted

Timber: TMT Composite®: FSC® certified, laminated, heat-treated beech
Finish: Water-based paint: two primer coats, then two or three top coats
Colour: Any RAL or NCS colour, or a transparent UV protection
Care: Doors that are not particularly exposed need no repainting for 25 to 35 years

Oiled

Timber: FSC® certified sapele mahogany or European oak
Finish: Cold-pressed linseed oil, clear or black-pigmented
Option: A transparent UV treatment that behaves like paint, with no oiling for many years
Care: Oil at least three times in the first year, then twice a year

Finish examples 7

Lacuna’s own samples. Select any to add them to your project enquiry.

Any RAL or NCS colour

Browse the RAL Classic range here. For an NCS colour, give us the reference in your enquiry.

Also available

Two and three colour combinations A darker colour outside and a lighter one inside is a common choice, and oiled timber can be combined with paint.
Textured finishes and clear coat Various textured finishes, and a clear coating similar to lacquer.
Panels Supplied in the same colour as the rest of the door.

Colours on screen are a guide only, and pearl and metallic finishes cannot be shown. Add your choices to your project enquiry and we will go through them with you.

Add to project enquiry

Source: Lacuna’s folding door pages on surface treatment and colour combinations, and their maintenance guide.

FAQs

Common questions, answered.

The essentials on the Lacuna Folding Door: what it is, how it performs, the options, and where it fits best.

Still have a question?

Our team can talk you through the detail for your project.

Ask a question +44 (0)1743 612 110

How much of the opening can a Lacuna bifold clear?

Depending on the configuration, the folding door can provide a clear opening of up to 90%.

How large can a Lacuna folding door be?

Published guidance covers made-to-measure widths from 1.5 m to 6 m, heights up to 2.8 m and panels up to 1 m wide.

What thermal performance is available?

The supplier publishes an indicative Uw of 1.05 W/m²K with comparable double glazing and values as low as 0.8 W/m²K with standard triple glazing.

Why is the system top hung?

The door panels run from an integrated track in the head frame. This keeps the running mechanism out of the threshold and makes the stability of the supporting lintel an important design consideration.

Which timber and finish options are available?

Options include painted heat-treated beech, European oak and FSC-certified sapele mahogany, with painted, UV-treated and oiled finishes depending on the timber.

Downloads

Drawings and technical data.

9 files for this system, published by Lacuna. Tell us who you are once and everything here opens for the rest of your visit.

System drawings 2 Frames, sections and system overviews

Design options 1 Glazing bars, panels and colours

Installation and care 3 Fitting, packing and maintenance guidance

Certification and testing 2 Independent test results and certificates

Environmental declarations 1 EPDs and environmental data