Sanding and Polishing Marble Walls and Columns: Renovating Vertical Surfaces On Site

When marble floors wear out, everyone notices; marble walls and columns, however, age quietly. The head-height part of a lobby column goes dull from hands, the corners of the cladding in an elevator hall chip from suitcase and trolley impacts, and the lower part of a wall gets stained by cleaning water and mop splashes. Most of these surfaces can be honed and repolished in place without being removed. But working on a vertical surface is very different from working on a floor: the weight of the machine is of no use, water runs downward, and the curve of a column reflects the slightest carelessness. In this article we explain how wall and column honing is planned, which machines are used, how water and slurry are controlled, and why scaffolding and protection are an integral part of the job.

In short: Vertical marble surfaces are honed from top to bottom with very little water, using light hand machines with adjustable speed and flexible pads. Before work begins, the soundness of the cladding is checked, and the floor and surroundings are protected against water and slurry. Columns require continuous, uninterrupted movement so as not to distort the curve of the surface; for high sections, a scaffold with guardrails and locked wheels is used.

Why Is a Vertical Surface a Separate Job?

In floor honing, the machine's own weight presses the abrasive evenly against the stone. The operator only guides the machine. On a vertical surface, this weight does not exist; the pressure comes from the craftsman's arms. If the pressure is not even across the surface, one area wears more and another less, and visible waves form on the surface. Since holding a machine in the air for a long time is tiring, the quality of the work depends largely on the craftsman's experience and working rhythm.

The second difference is gravity. On a floor, water and slurry stay in place or are collected in a controlled manner. On a wall, every drop runs downward and leaves marks on the already finished surface below, on the skirting and on the floor. The third difference is access: the upper parts of walls, column capitals and borders near the ceiling can only be worked on with scaffolding. These three differences make wall honing slower and more preparation-intensive than floor honing.

Vertical surfaces also have an advantage. Because walls and columns are not exposed to the abrasion of sand under shoes, they are generally much less worn than floors. Most walls have no deep scratches or lippage; dullness and stains can be removed with medium and fine grits, without the need for coarse stages.

First, Get to Know the Cladding

Before starting the honing, it must be understood how the cladding is fixed to the wall and what condition it is in. Interior marble cladding is mostly bonded to the wall with mortar or adhesive; on some tall lobby walls and façades, however, the slabs are hung on the supporting structure with metal anchors. In both systems, there may be voids, loosening or anchor problems behind the slab.

To get to know the cladding, several observations are made during the survey. The slabs are tapped lightly; a slab that sounds hollow may have a void behind it. The joints are checked for opening, the slab edges for breakage, and the gap between wall and slab for movement. The vibration of the honing machine and the pressure of the craftsman can shift a weakly attached slab, so problematic slabs are secured before honing. We covered the general characteristics of anchored cladding systems in our article on dry-fix façade anchors as well.

Everything around the cladding is also marked during the survey. Electrical sockets, light switches, elevator call panels, fire cabinet doors, timber door frames and glass partitions are points that need to be protected and that also determine how close the machine can approach.

Hand Machine and Pad Selection

On vertical surfaces, hand machines are used instead of floor machines. These are light stone polishing machines with adjustable speed, usually with a water feed. The pads attach to the machine's backing plate with a hook-and-loop surface; to change grit, the pad is removed and a new one fitted. Flexible, resin-bonded diamond pads are preferred on vertical surfaces because they follow the slight undulations of the stone and avoid the sharp marks a rigid pad can leave.

Speed selection is important. High speed lets the abrasive work the stone quickly but also increases heat and water splash. Since water splashing on a vertical surface spreads to the craftsman's face and the surroundings, the speed is generally kept moderate and the machine is used parallel to the surface, pressed flat. Pressing with the edge of the machine leaves hollow rings on the surface; this is one of the most common mistakes in vertical honing.

Electrical safety is especially important with a hand machine. Because water and electricity are used together in the same tool, and in the craftsman's hand at that, the machine must be fed from a line with residual current protection, and cables must be kept away from the path of the running water. We explained the general precautions taken during honing in detail in our article on occupational safety in honing in detail.

Water and Slurry Control

The part of vertical honing that requires the most preparation is water management. In wet honing, water cools the abrasive and binds the dust; but since it runs down the wall, much less of it is used than in floor honing. Most of the time, the machine's water feed is opened to the lowest level, or water is applied only to the work area with a spray bottle.

Wall honing generally proceeds from top to bottom. This way, the slurry running down from above falls onto lower areas not yet worked and does not soil the finished surface. When each section is done, the surface is wiped with a damp sponge and dried. At the foot of the wall, a plastic channel or an absorbent strip fixed with tape is used to collect the slurry; the floor is also covered with a wide sheet.

The main precautions taken on site so that water and slurry do not damage the surroundings are as follows:

• Floor protection: The floor at the foot of the wall is covered with a waterproof sheet and an absorbent layer, and the edge where the sheet meets the wall is taped down to prevent slurry from seeping underneath.
• Sockets and switches: The circuit protection of the electrical points on the cladding is switched off together with an authorized person, and the covers are wrapped in waterproof tape and plastic.
• Adjacent materials: Timber frames, glass partitions, stainless steel panels and skirtings are protected with tape, and slurry is not allowed to dry on these surfaces.
• Dry option: Where water is not wanted at all, the dry method is applied with dust extraction connected to the machine and suitable respiratory protection.

Columns and Round Surfaces

Columns are the part of vertical honing that demands the most skill. On a flat wall, the machine sits flat on the surface; on a round column, the surface is curved at every point and the machine's flat plate touches only a narrow strip. If the craftsman holds the machine in the same spot, it cuts a flat band into the curved surface; seen from the side, the column starts to look angular. For this reason, in column honing the machine is kept constantly moving and advances around the circumference of the surface with even pressure and overlapping passes.

Flexible pads play a decisive role here. Thinner, more flexible pads follow the curve of the column, and for narrow-diameter columns, machines with smaller backing plates are used. Some craftsmen work the column in horizontal bands, others in vertical strips; what matters is to check with raking light that the marks of one grit have been removed evenly across the whole surface.

Fluted columns, capitals and profiled bases cannot be fully worked with the machine. The insides of the flutes and the curves of the profiles are worked by hand with diamond-impregnated sponges, hand pads or small rotary tools. These sections require labor and must be accounted for separately in the work plan. Cylindrical columns are often made up of several pieces stacked on top of each other; the joints between the pieces are also renewed with filler and honing.

The head-height section of columns is generally the most worn part. Contact with hands, the rubbing of bags and unsuitable products used during cleaning leave dullness and stains in this area. In some jobs, only this section is renewed instead of the whole column; in that case, however, the transition must be made gradually so that no noticeable difference in gloss remains between the renewed section and the upper part.

Scaffolding, Access and Work Area

The upper parts of walls and columns must be worked on with scaffolding, not a hand ladder. A hand machine is used with both hands, and the craftsman must keep his balance while applying pressure; achieving this balance on a ladder is neither safe nor compatible with even pressure. Indoors, mobile scaffolds with wheels, guardrails and wheel locks are generally used.

The floor where the scaffold is set up must also be protected. Pads are used so that the wheels do not leave marks on the marble floor, and a floor cover is laid before the scaffold is positioned. The area around the scaffold is closed off with barriers and warning signs for pedestrians; especially in lobbies that remain open, a tool that could fall from above or splashing water poses a risk to those passing below. Measures and responsibilities regarding work at height are regulated separately in occupational health and safety legislation; on large jobs, expert support should be obtained on this matter.

Lobby and Elevator Hall Examples

The two areas where vertical honing is most often requested are building lobbies and elevator halls. Both are places that are in constant use, carry prestige and have sensitive materials around them.

Plaza and hotel lobby walls

In plaza and hotel lobbies, marble walls are generally clad with wide, tall and large slabs. Here the work is mostly planned at night, section by section; each night one or two walls or a few columns are completed. The mobile scaffold is moved from one section to another, and the floor cover and barriers are set up again for each section. In lobbies, wall honing is often planned together with floor renovation; in that case the walls are worked first, because the slurry running off the wall falls onto the floor, and the floor is honed last. We covered the overall floor management of lobbies in our article on plaza lobbies separately.

Elevator halls

Elevator halls are small but complex areas. Between the marble cladding there are call panels, floor indicators, stainless steel door frames and fire cabinets. The most worn points in this hall are the corners on both sides of the elevator doors and the area around the call panel; impacts from trolleys, suitcases and cleaning carts chip the corners, and hands dull the area around the panel. Before honing, broken corners are repaired with color-matched filler, and the panels and stainless steel surfaces are protected with tape. Working hours for the elevators are agreed with the building management; while the hall is being worked, the door on that floor is kept from opening.

Decision Table for Wall and Column Honing

The table below summarizes the main difficulties encountered on different vertical surfaces and the approach followed:

Choosing the Finish and Aftercare

Since slip resistance is not a concern on walls and columns, a polished finish can usually be chosen without hesitation. On lobby walls, a polished surface reflects light and the depth of the space, giving columns a stately look. In wet areas, such as hotel bathrooms or spa walls, a satin finish is a practical option because it shows water and soap marks less.

After honing, applying an impregnating sealer to the head-to-hip-height section of the walls slows the absorption of hand oils and stains into the stone. For daily cleaning, a damp microfiber cloth and a pH-neutral product are sufficient; glass cleaners and all-purpose sprays can leave dullness on marble over time because of the chemicals they contain. If you are curious about how hollow slabs are fixed, you can also take a look at our article on injection repair .

If the lobby, elevator hall or stairwell of your building has dulled marble walls and columns, most of them can be restored in place without being removed. You can reach us through the service request form with general and close-up photos of the surfaces; during the survey, we examine the condition of the cladding and prepare a section-by-section work plan.