Fluid Glass Link: Frameless Glass Link Extensions Between Buildings

A glass link is a short glazed connector between two parts of a building. It can also work as a glazed corridor between two structures. Ours is built from structural glass panels bonded edge to edge, using frameless glass for a completely frameless look, so the junction between one pane and the next is 8mm of structural silicone in an assembly 35mm across, rather than a post, which adds to its aesthetic appeal. Panes run to 6m high and 3.2m wide; wider elevations are composed from several, joined the same way. Looking through it you get unobstructed views of the building on the other side, while natural light reaches interior spaces and helps the link support a brighter living space.

The glass is the same unit we use for vertical structural glazing: 69mm triple glazed or 54mm double, on a profile 79.15mm deep with a 30mm polyamide thermal break, custom designed around the project’s requirements. The thermal break matters more in a link than almost anywhere else, because a link is glass on every side and has no solid wall to fall back on, and double or triple glazing enhances insulation and energy efficiency.

Those are whole-window figures measured on a 2 x 2m unit, not centre-pane values. A centre-pane number is always lower and tells you nothing about the frame it sits in. triple glazing reaches Uw 0.9 on a Ug of 0.6; double glazed reaches 1.1 on a Ug of 1.0. A link built to the triple-glazed specification meets Part L, and the double-glazed option can also satisfy current energy regulations where appropriate.

Water comes off the face of the glass, that's how links are normally built and it is the detail that asks least of you afterwards, because there is no channel to clear. It does need a fall, so the roof pitch is not a free choice. At Chiltern Hills we detailed a concealed gutter behind the structural panels instead, so the glass roof read as a single plane from both sides. That was drawn for that project rather than taken off the shelf, and it takes longer to detail; more complex drainage and junction detailing can also increase installation cost. Either is available. The choice usually comes down to how much of the junction you are willing to see, though a solid roof may suit overlooked sites where privacy matters more.

Anything over your head is toughened laminated, which holds together in the interlayer if it breaks rather than coming down. It is rated for maintenance access, not for walking on. If you want a surface you can stand on, that is a glass floor and a different build-up.

Links rarely join two buildings that are square to each other. At Crown Lane, which also has Fluid X minimal sliding doors on 20mm frames, the connector is two non-orthogonal panels, shaped individually and joined above an internal wall so that the junction is invisible from inside. Odd angles are a drawing problem rather than a manufacturing one, provided they are known early.

At Crown Lane the junction between the link roof and the SIPs pavilion needed a roof support strategy and link design that were carefully designed around the roof junction, because the glass could not provide enough support on its own, so an internal structural wall went in to carry it. A structural engineer may also be needed where differential movement between the existing structure and the new link has to be managed. That decision belongs in the drawings, not on site. A link that has to be re-engineered during installation has usually been specified too late, especially where components are made to precise specifications from detailed drawings and then installed by skilled professionals.

“On a link the awkward part is nearly always where it meets the existing building. We would rather draw it properly at the start than find it on site.”

Steven Towler, Sales Manager

Deflection is 0.055mm at 3300N. A link is short, so wind is seldom the governing case, but where support is needed it may come from steel supports or glass beams, depending on the design, and we will give the test data to your engineer rather than asking them to take it on trust; additional support requirements can affect cost.