All processes
PRC.51 · Construction Process

Frameless Glass Doors and Partitions

A frameless glass wall looks like the simplest of constructions: two profiles and a panel. In fact it is the one interior system where the site has no room to adapt anything. Toughened glass arrives finished and any attempt to correct it destroys it: the whole job is decided in the survey and in the preparation of the bedding line.

Typical thickness
10-12 mm toughened for leaves, 8+8 laminated for tall partitions
Self weight
about 25 kg/m² for every 10 mm of thickness
On-site machining
none: cutting, holes and cut-outs precede the toughening furnace
Production lead time
2-6 weeks from the final survey, not from the design

Overview

TAV. 00

The process covers frameless glass doors and interior partitions, from the instrument survey on completed rough work through to functional commissioning and safety marking. The sequence is rigid for a physical reason: cutting, grinding and drilling must precede the toughening furnace, and after the furnace no machining is possible any more. The site therefore receives an unmodifiable component and has to build a compatible opening around it, not the other way round. The phases follow that logic: first measure reality, then correct the bedding line, then install, adjust and commission. The recurring defects — spontaneous breakage, edge chipping, wedge-shaped joints, doors out of adjustment — almost all come from inverting that order.

The site score

TAV. H
NOT TO SCALE0 of 5 layers in place

The detail of the craftThe real opening is not a rectangle

L1L2L3L1 = L2 = L3 quasi mai
01Weeks 1-2

Survey once the rough work is done

Frameless glass panels are made to measure and arrive finished: edges ground, hardware holes already drilled, toughening already done. None of these operations can be repeated on site. That is why the survey is not taken from the architectural drawing but from the structure as actually built, after screeds, plaster and suspended ceilings have reached their final level. Every opening is measured at three heights — top, middle, bottom — and out-of-plumb and out-of-square are recorded, because the panel is a rigid rectangle that has to fit into an opening which almost never is.

Why it is done this wayA hole cannot be drilled in a toughened panel afterwards: toughening holds the surface in compression and the core in tension, and drilling or cutting releases that energy, blowing the panel into granules. Every machining operation has to precede the furnace. The survey is therefore the last moment at which a mistake is cheap.
3 · measurements per side of the opening0 · operations possible after toughening2-6 · weeks of production after the survey
In handLaser distance meterDigital levelPlumb lineOne-metre squareWorkshop survey sheet
Survey only after screeds, plaster and suspended ceilings are complete
The mistake that costs dearlyOrdering the panels from the design dimensions to gain lead time. The actual opening almost always differs by a few millimetres, and on a frameless glass wall those millimetres become an irregular joint visible to the naked eye.
Site supervision checkCheck that the survey record is dated after screeds and plaster are complete and that it gives, for each opening, three height and three width measurements, not just one.
Instrument survey of the openings once rough work is complete, returning actual dimensions at three points per opening and recording out-of-plumb and out-of-square; production of the shop drawing for each panel.site notebook — editorial synthesis
The beats — with site daysbeat 1 of 5
2-6 weeksManufacture of the made-to-measure panels: grinding, drilling and toughening happen in the workshop and cannot be compressed without giving up a control step.
24-48 hoursCuring of the neutral silicone sealant before stressing the joint, cleaning the edge or putting the door into service.

click a beat · arrow keys ← → walk the site · dashed pauses are the chemistry at work

PLATE 01

Toughening is a point of no return

TAV. G1

The furnace closes the list of possible operations. Everything the panel needs — size, edges, holes, cut-outs, printing — must exist before. Afterwards, the site can only install.

A — SEZIONE DELLA LASTRACOMPRESSIONECOMPRESSIONETRAZIONE — CUOREPUNTA DEL TRAPANOForare la superficie in compressione libera il cuore in trazione:la lastra si frantuma per intero, non si crepa e basta.B — SEQUENZA OBBLIGATA01 TAGLIO A MISURA02 MOLATURA DEI BORDI03 FORI, INTAGLI, SERIGRAFIE04 FORNO DI TEMPRAPUNTO DI NON RITORNO05 CANTIERE — SOLA POSAARCHITHECA — PRC.51

The diagram illustrates the logic of the process. Thicknesses, tolerances and performance requirements are to be taken from the design and the applicable product standards.

PLATE 02

The opening is not a rectangle: where the difference ends up

TAV. G2

There are always a few millimetres between the drawing and the wall as built. In a frameless system those millimetres do not disappear: either the adjustment range of the profile absorbs them, or they become a visible joint.

A — IL VANO COSTRUITOabLASTRARETTANGOLO RIGIDOLa lastra è rettangolare, il vano quasi mai. La differenza a meno bnon sparisce: cambia solo di posto.B — IL CAMPO DI REGISTROLASTRACAMPO DI REGISTROCUNEIIl profilo assorbe la differenza fino al suo campo di registro.Oltre quel limite, la fuga diventa visibile a occhio nudo.

Proportions are exaggerated for legibility. Installation tolerances and permitted clearances are to be taken from the design and the applicable standards.

How it ages (and what betrays it)

TAV. P
PT.01Spontaneous breakage from nickel sulphide inclusion. The panel shatters with no impact, even months after installation, because of the expansion of a micro-inclusion present in the glass since melting. It is not an installation defect and cannot be seen by eye: it is reduced by ordering panels that have undergone a heat-soak stabilisation treatment and managed by allowing for replacement in the contract.
PT.02Edge chipping during handling. A knock on the edge, even a slight one, leaves a chip that concentrates stress; failure may arrive weeks later. The edge has to be protected at every stage and any chipped panel must be rejected, not installed in the hope that it will hold.
PT.03Wedge-shaped joint from an out-of-square opening. The panel is rectangular, the opening is not. If the difference has not been absorbed in the bedding line and in the sizing, it stays visible as a joint that opens progressively from top to bottom and that no sealing can disguise.
PT.04Door out of adjustment. The leaf does not return to its closed position, slams or stays ajar. It comes from a floor closer set before the door was plumbed, or from a base profile anchored in the screed alone that has failed under repeated loading.
PT.05People walking into unmarked panels. A clean, unmarked panel is read as a free opening. The impact typically happens in the first days of use of the building, before people have learned the plan, and that is precisely the period when the marking is most often still temporary.

Questions from the site

TAV. Q
Can I have a hole drilled on site to add a handle?

No. Toughened glass cannot be drilled after treatment: toughening holds the surface in compression and the core in tension, and the hole releases that energy, shattering the whole panel. If an extra handle is needed, the panel has to be remade with the new holes before the furnace.

Why does the wall cost more when the opening is irregular?

Because every panel becomes a one-off. In a regular opening the panels are identical and can be replaced from stock; in an irregular one each has its own dimensions, and replacing a broken panel means a new made-to-measure production run taking weeks.

Are laminated glass and toughened glass the same thing?

No, and they are not alternatives: they answer two different problems. Toughened glass breaks into blunt granules but falls all at once; laminated glass keeps the fragments bonded to the interlayer and stays in place. Tall partitions and balustrades use laminated glass precisely because the broken piece has to stay where it is.

How much noise does a frameless glass wall actually stop?

It depends almost entirely on the edges, not on the panel. Glass is heavy and stops airborne noise well; it is the ceiling joint, the door closing edge and the path under the raised floor that let sound through. A double partition with continuous seals performs far better than a single thick panel: declarable figures must be taken from the test reports for the specific system.

Materials involved

TAV. M