How to Measure for a Shower Enclosure

When to Measure

The correct moment is after tiling is complete and after the shower base or the floor build-up is in place. Not before.

Tile and adhesive commonly take 12 to 20 mm off each wall, and that is not a constant across a room. An enclosure measured from the substrate will be too wide, and there is nothing to be done about it once the glass is toughened.

Two different numbers get used loosely in early conversations, and mixing them up is the single most common measurement error: the rough opening is the framed or tiled gap before final surfaces are complete, useful for early planning but not what production uses. The finished opening is the actual gap once tiling, waterproofing membrane and any wall lining are done, and it is the number a shower enclosure is built against. Mark clearly which figure is being sent, since a rough-opening number read as a finished measurement produces an enclosure that will not fit.

This creates a scheduling conflict on every project, because the enclosure has a lead time and the tiling is late in the program. The answer is to plan for it rather than to measure early: order the enclosure against a survey taken at the right moment and accept the lead time, or choose a framed configuration whose adjustment absorbs the uncertainty.

• Measure after tiling and after the shower base is set
• Never measure from bare substrate for frameless work
• Build the enclosure lead time into the program deliberately
• Where the schedule cannot allow it, choose an adjustable configuration
• Record the date and stage at which the survey was taken

Width, at Three Heights

Measure the opening width close to the shower base, at roughly mid height, and near the top of the intended glass. Record all three.

For a framed enclosure the smallest measurement governs, and the profile absorbs the difference. For a frameless enclosure the smallest also governs, but the difference will be visible as a tapering gap, so if the spread between the three is more than a few millimeters, that is information the supplier needs before production.

For a corner enclosure, do this on both openings, and also measure the diagonal to establish whether the corner is actually square. A corner that is 5 mm out over 900 mm will show clearly in a frameless installation.

• Three widths: low, middle, high; the smallest governs
• Record all three, not just the smallest
• For corners, measure both openings and the diagonal
• Report the spread to the supplier before production
• Note which wall each measurement was taken from

Plumb, Square and What They Cost

A wall that leans is the most common enclosure problem and the one most often discovered at installation.

Check both side walls with a long level and record how much they deviate over the height of the glass. A framed enclosure can typically hide 10 to 20 mm through its adjustable wall profile, depending on the product. A frameless one has a wall channel with a few millimeters of adjustment at most, beyond which the deviation appears as a wedge-shaped gap at the top or bottom of the panel.

If the deviation is large and a frameless result is wanted, the options are to correct the wall, to accept a visible taper, or to specify a configuration with a wall profile. All three are legitimate; what is not legitimate is discovering the choice on installation day.

• Check both side walls with a long level over the full glass height
• Record the deviation as a number, not as an impression
• Framed profiles typically absorb 10 to 20 mm; frameless absorbs a few
• Decide in advance whether to correct the wall or change configuration
• For repeat rooms, survey a sample rather than assuming they match

The Floor, the Fall and the Door

Water control in a frameless enclosure depends on the floor as much as on the glass. Before setting out, confirm which way the floor or shower base falls and where the drain sits.

A floor that falls toward the door opening will push water out no matter how well the enclosure is made, and it will be reported as a leaking enclosure. In a wet room with a linear drain, check that the fall is toward the drain across the whole showering area, not just near it.

Also note the shower head position relative to the door. A head aimed at the opening is a design error that no seal will correct, and it is easy to fix on a drawing and impossible to fix afterward.

• Confirm the fall direction and the drain position before setting out
• A floor falling toward the opening will leak regardless of the enclosure
• Check the shower head is not aimed at the door
• For walk-in screens, confirm the wet area is long enough
• Record the shower base raised edge height if one is fitted

Door Operation and Clearance

The opening width tells the supplier how big the glass needs to be. It does not tell them how the door should move, and that decision changes what else has to be confirmed.

A hinged or pivot door needs clear swing space inside or outside the enclosure, and the handing — left or right — has to be fixed before production, since it cannot be reversed on toughened glass. See sliding vs hinged shower doors for how the two operations compare on swing space and hardware. A sliding door needs no swing space but needs enough wall run for the panel to travel, and buyers should confirm which panel is fixed and which one moves. Where a return panel or a second fixed panel closes off a stub wall, its width and any step in the wall behind it should be recorded separately from the main opening.

Hardware finish, handle style and any special cut-outs for a fixed shelf, bar or niche opening should also be confirmed at this stage rather than assumed from a catalog image, since these details sit on the approved drawing alongside the dimensions.

• Confirm hinged, pivot or sliding operation before measuring swing or travel space
• Fix door handing (left/right) — it cannot be changed after toughening
• Record fixed panel and return panel widths separately from the main opening
• Confirm hardware finish and any special cut-outs on the drawing, not from a catalog photo

Walls, Threshold and Mounting Conditions

Plumb and square cover the two side walls. Two more conditions decide whether the enclosure can actually be fixed in place: what the door threshold does, and what is behind the wall where the hardware attaches.

Confirm the shower base or floor raised edge height where the door will close, since a door cut for a flat floor will not clear a raised shower base lip. Note whether the wall the hardware fixes to is solid, tiled masonry, or a lightweight partition — heavier glass and larger hinged or pivot doors need a wall structure capable of taking the fixing load, and a partition wall may need backing or blocking added behind the tile before installation, not after. This is a site condition to confirm with whoever built the wall; WNS Global reviews the wall and hardware information a buyer provides, but confirming the actual wall structure and backing on site remains the buyer’s or their contractor’s responsibility.

Where a bathroom niche or other wall cut-out interrupts the enclosure area, its position relative to the opening should be measured and marked on the same drawing as the main dimensions.

• Confirm shower base or floor raised edge height at the door position
• Identify the wall structure behind any hardware fixing point
• Confirm whether backing or blocking exists, or needs adding, before installation
• Mark any niche or wall cut-out inside the enclosure on the drawing

Technical Drawing Approval

Every measurement above exists to go on one drawing: opening width at three heights, plumb deviation, floor fall and drain position, door operation and handing, panel widths, wall backing condition and any cut-outs. Production starts from that drawing, not from a verbal description or a marked-up floor plan.

WNS Global reviews the submitted measurements against the requested configuration for our custom shower enclosures and the wider shower enclosure range, and returns a drawing for sign-off before cutting or toughening any glass. Confirm every dimension and note on that drawing matches the site condition — a drawing approved without a final check carries the same risk as glass ordered from an unverified measurement.

This review confirms the drawing matches the information supplied; it does not replace an independent site survey or structural check, which remains the buyer’s or their contractor’s responsibility where local conditions require one.

• Consolidate every measurement onto one drawing before production
• Treat drawing approval as the final checkpoint, not a formality
• Re-check the drawing against the actual site, not only against the order
• Keep the signed-off drawing on file for reference during installation

Common Sourcing Risks

Most shower enclosure disputes trace back to one of a small number of avoidable gaps between what was measured and what was actually built.

None of these risks require special tools to avoid. They require the measurement, the wall check and the drawing approval to happen in the right order, before any glass is cut.