Skla pro panely vchodových dveří: mat, Delta 2, Stopsol

Glass is the one element in a decorative panel that has to do three jobs at once: let light in, keep the street from looking in, and survive being hit. That is why it is chosen by different rules than window glass. In a window, thermal performance leads. In an entrance door, visibility, the direction of the light and safety lead — in that order.

Why door glass follows different rules

An entrance door sits on the boundary between the street and the hallway. During the day the bright side is outside; in the evening it is inside — and the same pane behaves differently in the two cases. Add that the leaf gets slammed, that pushchairs, bags and children hit it, and that the glass usually sits at eye height. A window rarely lives that life.

There is a third difference every fitter knows: glass in an entrance door panel is almost never a plain rectangle. It is cut to shape, its edges are ground, and it is sometimes drilled for a handle or for decorative hardware — and all of that has to happen in a strict order, which we come back to below.

Thermally, glass itself is not an insulator. The thermal conductivity of float glass is roughly 0.9–1.0 W/(m·K) — tens of times higher than the insulating core of the panel around it. So glass is treated as a functional opening: the insulation comes from the sealed unit and from the solid area around it, not from the glass surface. If you are comparing numbers across materials, see the technical parameters of panel materials.

Frosted glass: acid etching versus sandblasting

Frosted glass is the most requested option for an entrance door, and for good reason: it gives soft, diffused light in the hallway and removes any clear image from outside. But “frosted” describes the result, not the process — and there are two processes that age very differently.

Acid etching dissolves the surface chemically and leaves a smooth satin finish. It feels velvety rather than rough. Sandblasting mechanically blasts micro-craters into the glass and leaves a visibly coarser layer.

The practical difference is maintenance. That rough sandblasted layer holds grease, dust and fingerprints, and over time the marks become hard to remove because they have settled into the texture. An acid-etched surface stays noticeably cleaner and wipes down with an ordinary cleaner. On a door that gets pushed by hand every single day, right next to the glass, that is not a small detail — see also our care guidance.

White (back-painted) glass — solid colour, with one real limitation

White glass is neither frosted nor painted on the face. It is float glass with a coloured lacquer applied to the back. Viewed from the front, through the glass, the colour reads deep and perfectly even, with a wet gloss no laminated surface achieves. Zero visibility, maximum contrast against stainless hardware — which is why it works so well in contemporary panels.

Here is the caveat a fitter needs to know and pass on to the customer: the standard product of this type is specified for interior use. That is how the manufacturer’s own specification describes Lacobel-type lacquered glass — float glass with paint on one side, intended for indoor applications. The reason is structural: the paint sits on the inner face, and the glass protects it only for as long as moisture and UV do not reach the edge and the back.

That does not mean white glass has no place in an entrance door. It means it must be set so the painted face looks inward into the construction, sealed against moisture at the edge and at the back. In practice that means white glass on the inner face of a sealed unit, or behind the solid build-up of the panel — not as the outer face taking the rain and the sun. If the door is on an open landing, south-facing, with no canopy above it, that is a conversation to have before the order, not after the first winter. For anything unusual, go through made-to-measure orders.

Delta 2 and patterned glass — light without a view

Patterned glass is made by rolling a relief into the surface. The Delta pattern is one of the classics: geometric, calm, free of any retro flavour, and equally at home in a traditional or a modern panel. It exists in two main versions that are frequently confused:

• Delta Clear — a clear base with the relief. It gives partial visibility: you make out a silhouette and movement, but not detail.
• Delta Frost — the same relief on a frosted finish. It hides the view completely.

Choosing between them is a question about how you live: do you want to see that someone is at the door, or do you want full opacity. For a shared corridor, Frost is usually the calmer answer; for a door onto your own garden, Clear keeps a connection to the outside. See how both read in a finished panel in the catalogue.

Stopsol — the mirror effect and the day/night flip

Stopsol is reflective glass with a pyrolytic (hard) coating, applied while the glass is still on the hot production line. The important consequence of “hard” is that the coating resists scratching and tolerates secondary processing — it can be used monolithic, laminated or bent, as well as inside a sealed unit, and it can even be enamelled and screen printed. Soft coatings do not take that kind of handling.

It comes in three main variants: Classic with an amber tone, Supersilver with a silver mirror appearance, and SilverLight with weaker reflectivity for a more discreet effect.

And here is the part that is most often missed: the mirror effect works from the brighter side. During the day, when it is brighter outside, the glass reflects and the street sees a mirror — exactly what you wanted. In the evening, when the hall light is on and it is dark outside, the direction flips: the outside can now see in, and from inside the glass turns into a mirror. If the door faces a street and the hallway stays lit late, this should be known in advance. A Stopsol pane combined with a frosted one inside a sealed unit solves it without losing the look.

Safety: EN 12150 and EN 12600 are not the same thing

These two standards get mixed up constantly in quotations and conversations, and they describe different things.

EN 12150 covers thermally toughened glass — the product and the process. Toughened glass is far stronger in impact and bending than ordinary glass, and when it does break it falls apart into small blunt pieces instead of long cutting shards. That property is what saves hands and faces.

EN 12600 covers behaviour under soft body impact — what happens when a person falls against the glass. The test uses a pendulum dropped from a defined height, and the classes correspond to that drop height:

Why this matters specifically for an entrance door: glazing in a door leaf is a critical location. The critical zone covers glass in doors up to 1.5 m above finished floor level, and side glazed panels within 300 mm of the door edge. In other words, virtually every pane in an entrance door panel — and virtually every sidelight next to it — is in the critical zone by definition. Toughened glass here is not an upgrade; it is the baseline.

The short version for fitters: EN 12150 tells you the glass is toughened. EN 12600 tells you how hard an impact it withstands and at what class — 1B1, 2B2 or 3B3. The customer is entitled to see both, and it is in your interest to have both written into the order.

How the glass is processed: the order of operations is not optional

There is one processing rule whose violation is expensive and irreversible: toughened glass cannot be worked after toughening. Every hole, cut-out and edge treatment happens before it goes into the furnace. Trying to drill or re-trim already toughened glass does not chip it — it destroys the whole pane on the spot.

The real sequence is:

1. Cutting to size and shape — including arches, ovals and cut-outs for hardware.
2. Edgework — grinding or polishing. The edge must be clean, because micro-cracks in it are the starting point of every future break.
3. Holes and cut-outs — for handles, viewers, appliqués, positioned at a sufficient distance from the edge.
4. Toughening — the glass is heated and cooled under control. From this moment the size is final.
5. Assembly — into a sealed unit or straight into the panel.

The consequence for ordering is simple: dimensions and hole positions are fixed at the start, not adjusted on the fly. That is why a well-dimensioned panel starts from the exact door opening — the steps are set out in how to choose a panel.

Your own glass unit

If you already have a glass unit you want to keep — stained glass from an old door, a one-off pane specified by an architect, or a unit you ordered separately — it can be built into the panel, provided it meets the size and thickness requirements. There is one practical condition: the glass has to be assessed before the panel is made, not after. Its thickness sets the rebate, and the rebate sets everything else.

Whatever glass you have chosen, bring it into the conversation before the panel is ordered. Glass is the one component that does not forgive a change of mind — once toughened, it cannot be cut.

Which glass for which orientation

• North-facing, dark hallway — Delta Clear or a light frost. The goal is maximum light; visibility from outside is already limited by the brightness difference.
• South or west facing, strong sun — Stopsol. It reflects part of the solar energy and reduces overheating and glare in the hall.
• Door onto a street or a shared entrance — frosted or Delta Frost. Full opacity with no loss of light.
• Contemporary panel with stainless appliqués — white glass, provided the painted face is properly protected.
• Exposed landing, no canopy, south facing — do not use lacquered glass as the outer face; go for frosted, patterned or Stopsol.

Panels are made to order by a Bulgarian manufacturer, which in practice means the glass and its processing are specified for one particular door rather than picked from a short list of stock sizes. If you have not settled on the panel itself yet, start with the guide to decorative entrance door panels, and for the substrate carrying the glass, see what an HPL panel is.

Three things to remember: acid-etched glass stays clean far longer than sandblasted; back-painted white glass is specified by its manufacturer as an interior product and needs a protected build-up; and glass in an entrance door leaf sits in a critical location, so it must be toughened with a stated EN 12600 class.