Who this guide is for
- Owners specifying a mirror wall, a glass splashback or a panelled surface for the first time
- Anyone coordinating sockets, taps, brackets and appliances against a finished panel
- People running a fit-out programme where a long-lead panel sits on the critical path
- Readers weighing a made-to-measure panel against a site-cut material
- Anyone who has been asked to sign off a template survey and is unsure what it commits them to
Why these panels cannot be altered
The reason differs by product and the consequence does not. Toughening locks stress into the glass surfaces, so breaching a compressed surface releases the whole system and the sheet falls apart. Vitreous enamel is a glass layer fused into steel, so cutting or drilling breaks the face. A mirror or a back-painted panel carries its coating on the rear, and every new cut edge is an unprotected one the maker never supplied.
Compact laminate is machined off site with dedicated tooling after a template survey. Switchable glazing carries an active layer sealed inside a finished pane with its connection in a set position. In each case what arrives is a finished product, not a sheet of material that a fitter adjusts to the opening.
- Toughened glass: no cutting, drilling, notching or edge grinding after the furnace
- Vitreous enamel: every hole and fold formed before firing
- Mirror and back-painted glass: rear-coated, so site working exposes the backing
- Switchable glazing: pane made to size with the cable exit in a fixed position
- Compact laminate: machined off site to a template survey
The survey, not the order, is the point of no return
Templating happens after the wall, the units and the worktop are in their final positions, because a panel is made to the room as built rather than to the drawing. That means the survey cannot happen until the things it measures are finished, and everything that follows is timed from it rather than from when the order was placed.
The practical consequence is a scheduling one. A panel cannot be ordered early to save time, because ordering early means ordering from a drawing that the building will not match. Whoever owns the measuring has to be identified, because a measurement error here is unrecoverable rather than adjustable.
Everything behind the panel has to be finished first
A finished panel closes the wall permanently. Services, brackets, fixing grounds and any decoration behind it must all be complete, because nothing can be reached afterwards without removing or breaking the panel. On a switchable pane the cable route has to be designed before the partition is built, and retrofitting one into finished work is disruptive.
The background itself matters as much as the panel. A rigid panel bridges hollows and reveals them rather than following the wall, so flatness and soundness are part of the specification. With mirror, the adhesive has to be one the supplier accepts, because an incompatible adhesive shows as a bloom long after the installer has left.
Ironmongery, sockets and appliances are part of the panel
Holes in toughened glass are made to suit specific fittings, so a change of handle, hinge or bracket after fabrication usually means a new panel. On an enamelled wall every socket, rail and bracket position must be known before drilling, and a late socket move means a new panel and a new lead time.
This is why the selection of ironmongery and accessories moves forward in the programme. A decision that would normally be made when second fix arrives has to be made before the panel is ordered, and the person making it needs to know that.
Edges, handling and the damage that shows up later
Edges are where these products are weakest and where site damage concentrates. A chip at the edge of a toughened pane interrupts the compressed layer that holds it together, and an edge knocked in transit may not fail until later. Panels stored upright on an unprotected hard floor are the usual source.
On a mirror, water reaching a cut edge works in behind the backing, which is why the bottom edge tolerates standing liquid least well. On an enamelled panel a chip exposes bare steel and cannot be touched in. In all of them the practical protection is a planned delivery route, protected storage and a clear sequence with following trades.
Replacement, matching and what to keep
None of these is repaired in place. A chipped or scratched panel is replaced, which makes two records valuable: the template and the product reference. Keeping both is what makes a later replacement practical rather than a fresh survey of a room that has since been furnished.
Matching is the harder part. Tinted and antiqued mirror finishes vary between batches, enamel colour matching years later is difficult without the original firing batch record, and a decor range may simply not exist in a few years. A spare from the original run is worth asking for while the order is open.
Who decides what
Which glass type belongs in a given position, particularly where people may walk into or fall against it, is determined by a qualified professional against the relevant requirements. Heat exposure beside appliances, adhesive compatibility and cleaning are stated by the maker for the specific panel. The survey and the sequence belong to whoever is running the fit-out, and the owner signs off the template.
Before a made-to-measure panel is ordered
- 1Establish who is taking the template survey and who is accountable for it
- 2Confirm what must be installed and finished before that survey happens
- 3Fix every socket, tap, bracket and appliance position before templating
- 4Settle ironmongery selection, because holes are made to suit specific fittings
- 5Confirm the wall behind is flat, sound and prepared for the fixing method
- 6Agree the adhesive or fixing system with the panel supplier, not on site
- 7Complete services and decoration behind the panel before it is fitted
- 8For a switchable pane, design the cable route before the partition is built
- 9Plan the delivery route, handling and protected storage on site
- 10Ask what the maker states about heat exposure and cleaning for this product
- 11Keep the template drawing and the product reference with the building record
- 12Ask about spares from the same production or firing run while the order is open
Common mistakes to avoid
- Ordering from a drawing to save programme time instead of templating the room as built
- Moving a socket or a tap after the survey and treating it as a minor change
- Cutting a mirror on site, which creates fresh unprotected edges the maker never supplied
- Fixing a mirror tight into an unventilated recess where moist air is trapped against the backing
- Using whatever adhesive is in the van rather than the one the supplier accepts
- Storing panels upright on a hard floor with the edges unprotected
- Assuming the unpowered state of a switchable pane rather than confirming it with the maker
When to involve a professional
- Which glass type is appropriate in a given position, including anywhere people may walk into or fall against it, is determined by a qualified professional
- Heat exposure beside cooking appliances is governed by the maker's own guidance for the specific panel supplied
- Whether a wall can carry the weight of steel or glass panels and their fixing system is a matter for a qualified professional
- Wet-area use depends on the complete waterproofing and drainage strategy rather than on any single panel
- Fire-resisting construction is governed by the complete tested assembly and the relevant authority
Frequently asked questions
Questions readers ask about this topic
Why can toughened glass not be cut on site?
Toughening holds the glass surfaces in compression, and that locked-in stress is the product. Breaching the compressed surface releases the whole stress system and the sheet falls apart, so every dimension, hole and edge profile has to be made before the glass goes through the furnace.
When should the template survey happen?
After the wall, the units and the worktop are in their final positions, because the panel is made to the room as built rather than to the drawing. That is why a panel cannot be ordered early to save programme time, and why the survey rather than the order is the deadline.
What happens if a socket moves after the panel is ordered?
On a finished panel it generally means a new panel and a new lead time, because nothing can be cut or drilled after fabrication. That is the single most useful thing to tell everyone working on the room before the survey rather than after it.
Why do old mirrors go dark at the edges?
The reflective layer sits behind the glass, protected only by backing paints. Moisture reaching an unsealed edge, an incompatible adhesive, or liquid standing at a cut edge all attack it from behind, and the resulting dark creeping edge cannot be reversed.
Can a chipped enamelled or glass panel be repaired?
Not in place. A chip in fired enamel exposes bare steel and cannot be touched in, and a toughened pane cannot be worked on at all. Repair means replacement, which is why keeping the template, the product reference and a spare from the original run matters.
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