Pointing Brick Slips: Mortar, Joints and Finish

A contrasting mortar outlines each unit and makes the pattern more visible. A closer colour match gives the faces more visual continuity. A pale joint beside a dark slip can create a very different wall from the same slip surrounded by a darker joint. Compare the combination in the room’s actual daylight and evening lighting.

Think about profile as well as colour. A flush-looking joint and a recessed joint cast different shadows across a textured face. The depth and profile must remain within the system specification, so agree the desired appearance with the installer before making it part of the order.

The Cempoint mortar 25kg in our brick slips range has manufacturer documentation for walling. The linked Cempoint walling technical sheet states joint widths of 5–25mm and depths of 25–100mm. A shallow slip build-up may not provide that depth: ask Instarmac to confirm the actual joint before specifying it.

Do not assume the depth equals the slip thickness. Adhesive position and the intended finished profile affect the space available. Nor should extra depth be created by altering a designed backing or fixing bed. Send a section sketch showing the real build-up and use a compatible alternative if the proposed mortar is not approved.

Make the sample meaningful: several slips, actual joints and at least one representative change in colour or texture. Include the proposed corner detail if it is a prominent part of the project. Compare the panel after the materials have reached the condition specified for assessment, rather than approving only freshly mixed mortar.

For example, compare TBS Iced Grey with a lighter and a closer-toned mortar on separate sample panels. This is an appearance exercise, not a claim that every mortar is compatible with that slip. Photograph the accepted panel and record the product and colour names; a photograph alone is an unreliable colour reference.

Pointing cannot correct a layout that has drifted across the wall. Decide the pattern and nominal spacing during setting out, checking courses at openings and returns. The 10mm T spacers suit layouts specifying that width; they are not a universal requirement.

Read corners and reveals if the pattern continues around an edge. Show the installer which lines are ordinary pointing joints and which are specified movement or perimeter details. Those details need their own treatment. A neat continuous mortar line is not the right answer where the design requires movement.

Wait until the fixing stage is ready under the adhesive and system instructions. The Cempoint walling sheet calls for continuous joint filling and tooling after a semi-dry surface has formed, before the mortar becomes too stiff. Follow that sheet for the approved wall application; Instarmac publishes separate paving instructions with a different finishing sequence.

Arrange access so the installer can work consistently around openings and corners. Keep an agreed reference panel visible. Decisions about batches, mixing, timing and protection belong to the product instructions and site conditions; this guide does not substitute one universal recipe. The installation sequence explains how to coordinate fixing, pointing and final checks.

Agree how the wall will be protected and how accidental marks will be assessed before pointing begins. Deeply textured faces make residue particularly conspicuous in side lighting, so include a representative face in the trial panel. Protect adjacent painted surfaces, floors and fittings from the work.

Do not make a general brick acid wash part of the plan. The cleaning guide separates installation residue from routine household care. Use cleaning advice appropriate to the slip and mortar, with a trial in an inconspicuous area. Keep any chemical treatment out of the specification until compatibility is confirmed.

Inspect the wall from normal viewing positions, then check junctions and edges more closely. Compare the joint colour and profile with the approved panel and note incomplete areas for the installer to assess. If later cracking appears, investigate the cause before simply adding more pointing.

Keep the mortar name, colour, batch references and approved joint detail with the project records. This is more useful for future repairs than a description such as “light grey grout”. For more visual comparisons, read brick colours and mortar combinations before finalising the finish.