Stone Layout: Pattern Matching and Slab Marking

A stone layout is a drawing in which every cladding slab gets its own position, size and number, and the pattern of adjacent slabs is coordinated. For uniform granite the layout mainly solves geometry and minimises waste; for marble, onyx, travertine and other stones with a pronounced pattern it is also about beauty: veins should continue rather than break off, and shades should transition smoothly rather than blotch the wall.

The main criterion of a good layout is that it is based on the real slabs of a specific batch, not on a catalogue photo. Only then can you be sure the result on site matches what was approved in the visualisation.

A layout is needed by architects and designers, and by clients commissioning natural stone cladding for facades, halls, staircases and bathrooms. TECHNOFORMA prepares layouts as part of its stone services, together with measurements, 3D visualisation, installation and designer supervision. A general overview of stones is in the section Natural stone for facades and interiors.

Without a layout, stone is cut on site and every slab becomes a lottery. A layout solves several problems at once:

• Aesthetics. A marble and onyx layout creates a continuous pattern: mirrored (book-matched) pairs, veins running through several slabs, a smooth gradient of tone up the wall.

• Geometry. Joints are aligned with the axes of windows, doors and columns, corners and floor levels. No narrow cuts at openings and no slivers in corners.

• Quantity calculation. The layout gives the exact number of slabs, cutting and waste, and therefore the budget and purchasing schedule.

• Production. Each slab gets a size, edge finish and kerfs for fixings; the workshop cuts to a specification rather than verbal instructions.

• Installation. Installers fit numbered slabs according to the plan, without sorting on the scaffold.

For a facade on a rainscreen system, the layout also determines the spacing of the substructure rails and the position of the clips, which is why it is prepared before the shop drawings for the metal substructure.

Natural stone arrives as blocks that are sawn into slabs: large panels 20–30 mm thick or more. Slabs from one block come in sequence and have a similar, flowing pattern; slabs from different blocks can differ noticeably, even under the same trade name.

The workflow:

1. Block selection. For a large project, stone is taken from as few blocks as possible from the same quarry bed.

2. Numbering slabs in sawing order. The block number and slab number are kept all the way from the factory to the warehouse.

3. Photo record. Every slab is photographed under even lighting. The photos are the basis of the digital layout.

4. Sorting by tone and pattern. Slabs are grouped: light, dark, boldly veined, calm. Different groups are assigned to different areas, for example the most striking for the entrance and calmer ones for standard areas.

5. Rejection. Slabs with cracks, cavities or stains go to small elements or waste.

For uniform granites and limestones, sorting is simpler but still necessary: a slight difference in tone between batches is conspicuous on a large wall.

Marking links the layout drawing to the physical slab. Without it, even a perfect layout falls apart on the building site.

• The slab code usually includes the facade or room, the axis or zone, the row and a sequence number, for example “F1-A-03-12”. The coding system is fixed in the design.

• Where to mark: the back or edge, with a permanent marker or a moisture-resistant label. The face is never marked.

• Orientation: an “up” arrow if the pattern has a direction or if the slab has fixing kerfs on one side.

• Link to packaging: the crate or bundle lists the slabs inside and the installation section it is intended for.

• Schedule: a table of all slabs with dimensions, finish, source slab number and status (cut, shipped, installed).

Good marking makes it quick to order a replacement: if a slab breaks during installation, the code shows which source slab to cut it from so that the pattern matches.

A layout drawing is a scaled elevation of the surface to be clad with the slab grid drawn on it. The package usually includes:

The input data for the drawing are the architectural design and site measurements. TECHNOFORMA takes measurements with its own surveyors: actual wall and opening dimensions often differ from the design, and a layout based on the design alone without measurements leads to cutting on site. For curved and complex facades the layout is checked on a 3D model.

On site, the layout becomes a sequence of actions:

1. slabs arrive on site by installation section, in the order in which they will be fitted;

2. before lifting, each slab is checked against the schedule by its code and inspected for chips;

3. installation starts from a datum line (the plinth or the first horizontal level) strictly according to the plan;

4. joint widths are kept to the design, and deviations do not accumulate towards the corners;

5. installed slabs are ticked off in the schedule; broken ones are reordered by code from the same slab or the one with the closest pattern.

At this stage designer supervision checks that the pattern matches the approved layout, especially in book-matched areas and at entrances.

Common reasons for discrepancies between layout and result: slabs mixed up during unloading, crates opened out of section order, a broken slab replaced with whatever spare came to hand, wall deviations from vertical taken up in the joint widths. Each of these errors is avoided through discipline: storage by section, code checks before lifting, photos of installed areas at the end of each shift. On large facades, the photo record by section later also serves as as-built documentation.

An example of a TECHNOFORMA project with natural stone is the Dinastiya club house in Kislovodsk: 700 m² of granite together with 6,000 m² of GFRC (glass fibre reinforced concrete) and 700 m² of porcelain stoneware, designed and installed by the company. Layout details for this project are not published on the website, so we describe only the general scope: design, layout, measurements, installation and designer supervision are part of the company's stone services.

Other projects are in the TECHNOFORMA projects section. How to see the result of a layout before purchasing is explained in 3D visualisation of a stone facade before purchase.