What Are Split Face Blocks – How They’re Made & Where They’re Used in Perth

Split face blocks are concrete masonry units designed for visible applications – laid with the rough, fractured face exposed to create a textured wall surface that reads more like natural stone than standard block. They’re manufactured as regular masonry and then machine-split to produce the characteristic broken texture, and they’re used in residential feature walls, boundary fences, commercial façades, and retaining walls across Perth and nationally. The trade-off that comes up most often in contractor discussions and building inspections is the relationship between that exposed, porous surface and water management. This guide covers what split face blocks are, how they’re made, where they work well, and what maintaining them involves.

How Split Face Blocks Are Made

Machine-splitting and exposed aggregate

The manufacturing process starts like any concrete masonry unit: aggregate, cement, and water are mixed, compacted into moulds, and cured to produce a dense, hardened block. The distinguishing step comes at the end. Two blocks are cast together as a single larger unit, then a machine splits them apart along a scored central plane – and that split is what creates the textured face.

When the block fractures, the aggregate in the concrete becomes exposed along the break. Coarser aggregate mixes produce a rougher, more pronounced texture; finer mixes give a smoother version of the same effect. The resulting face is irregular – the fracture follows the path of least resistance through the material, so no two sections look exactly the same.

Why the texture looks different from standard block

Standard concrete block – besser block, hollow block, CMU – has a smooth, formed face on all visible surfaces. Split face blocks have one smooth back face used for bonding and one fractured front face exposed in the finished wall. That fractured surface creates depth and shadow that a mould can’t replicate: instead of a flat, uniform appearance, the split face shows variation and texture at close range that reads as stone character from a distance.

The construction dictionary definition of split face block as a “decorative masonry block with a rough textured surface” captures the intent well. It’s a standard concrete masonry unit: the splitting process adds the decorative finish, but the structural properties are those of conventional masonry.

What that means for appearance and durability

At wall scale, split face block reads as a textured natural material rather than concrete. The product is available in a range of colours depending on aggregate composition and any integral pigments – from natural greys and buffs through to deeper charcoals and warm earth tones – which allows it to work with most exterior palettes.

Durability is where the texture creates a separate consideration. The rough face has significantly more surface area and more crevices than smooth block, which affects how water interacts with the wall and how the wall needs to be detailed.

Where Split Face Blocks Are Used

Retaining walls and feature walls

Residential applications are where split face blocks appear most often in WA. Garden feature walls, boundary walls, and retaining walls that sit within the visible landscape are the most common uses – situations where plain block would look utilitarian and cladding isn’t necessary, because the block itself provides both the structural function and the decorative finish at the same time.

Remastone’s split face block range is designed for exactly this kind of application: walls that carry a structural load while also looking intentional within the design. The textured face ties in with natural and rendered exterior finishes without requiring a separate cladding system layered over the top.

Commercial façades and boundary walls

Split face block appears regularly in commercial construction – retail precincts, schools, commercial car parks, and industrial buildings where the exterior needs more presence than plain concrete block provides. The material’s structural performance and ease of installation at scale make it a practical choice commercially, and the decorative finish lifts the appearance of what would otherwise be a purely functional wall without adding the cost and complexity of a cladding system.

Commercial building inspection bodies have documented the moisture implications of split face block on external façades. CCPIA, a commercial property inspection resource, covers the surface characteristics and drainage requirements relevant to commercial building exteriors with split face block concrete.

When the finish is chosen for design, not just structure

There are also applications where the finish is the primary reason for specifying split face block – feature walls, planter boxes, and architectural elements where natural stone would be more expensive and standard masonry too plain. The structural capacity comes as a built-in benefit, and the design requirement leads the selection.

Benefits of Split Face Blocks

Stone-like appearance without the cost of natural stone. The fractured face creates texture and shadow – at wall scale the effect reads as stone rather than concrete. Published trade sources describe split face block as a “cost-effective alternative to natural stone,” which aligns with how the material is typically specified: projects that call for stone character on a concrete masonry budget.

Structural masonry performance. Split face blocks carry the same structural properties as standard CMU. They’re appropriate for retaining walls, boundary walls, and load-bearing applications where stone veneer products, which are decorative cladding only, would not work. The decorative finish doesn’t reduce the block’s compressive strength or its suitability for structural use.

Flexibility in colour and size. Available in multiple block sizes and aggregate colour options, split face block can suit projects ranging from residential garden walls through to commercial boundary construction. The product is manufactured to consistent dimensions, which simplifies laying sequences and material estimation.

Problems and Maintenance

Moisture intrusion concerns

The rough surface that gives split face block its visual appeal creates more pathways for water to enter the wall than a smooth block surface would. The textured face has more exposed surface area, more micro-crevices, and is harder to seal effectively than a flat moulded finish. Water sitting in the face during rain events can migrate into the block and, without adequate drainage and detailing, through the wall.

One guide to split face concrete block construction notes that the material has drawbacks compared to standard block, “particularly related to moisture intrusion.” Building inspection discussions – particularly from regions with high split face block usage on commercial buildings – reflect the same concern. Inspectors commenting in professional forums have described moisture intrusion as the primary risk with the material on exterior façades, with one forum contributor stating that split face block buildings can be “a losing proposition” when drainage isn’t addressed, while another cited “water intrusion damage and mold” as the most common consequence. These are forum comments attributed to specific markets and projects. The pattern is consistent: drainage and detailing matter more with split face block than with smooth block.

Efflorescence and staining

Efflorescence – the white powdery deposit that appears on masonry surfaces – is more common and more visible on split face block than on smooth-faced masonry. The mechanism is the same: water moves through the block, dissolves soluble salts in the concrete, and deposits them on the surface as it evaporates. On a flat surface, efflorescence deposits are easy to spot and clean, but the crevices in a split face give those minerals more places to lodge – they accumulate more readily over repeated wet-dry cycles.

Efflorescence doesn’t indicate structural failure, but persistent deposits suggest ongoing moisture movement through the block. Addressing it at the drainage or sealing level produces better results than surface cleaning alone.

Why drainage and flashing matter

Proper drainage and flashing reduce the moisture load on split face block substantially. Drainage behind retaining walls prevents hydrostatic pressure buildup, reducing the force pushing water through the masonry under pressure. Flashing at wall tops and at openings deflects surface water before it saturates the exposed face. Practitioners discussing split face block maintenance consistently identify drainage and flashing as the primary controls against moisture damage. A wall without them isn’t necessarily defective in the short term, but the cumulative moisture load will show up over years in the form of staining, efflorescence, and eventually interior moisture damage if the wall adjoins a habitable space.

Cleaning and sealing considerations

A breathable penetrating sealer is the standard recommendation for split face block. Breathable sealers allow water vapour to escape from the block while reducing liquid water ingress – which matters because a film-forming sealer that traps moisture inside the block can cause more problems than an unsealed surface would. For residential retaining and feature walls, reapplication every five to ten years depending on sun and rain exposure is a reasonable planning assumption.

Routine surface cleaning with water and a soft brush handles most accumulated grime. For efflorescence and mineral staining, a pH-neutral masonry cleaner is the right approach. Acid-based cleaners should be avoided – they damage the textured surface and interfere with sealer performance. High-pressure water directed into the face or into mortar joints can dislodge grout over time and should be used with care.

Split Face Block vs Alternatives

Split face vs smooth block

Split face and smooth concrete block are the same base product, separated by one manufacturing step. Both are concrete masonry units with identical structural properties – compressive strength, density, and load-bearing capacity are equivalent. The difference is entirely in the face finish: smooth block has a formed, flat surface; split face has a fractured, textured one. Smooth block sheds water more readily because there are no surface crevices for it to sit in. Split face has decorative character that smooth block lacks entirely. For any wall where appearance is a design consideration, split face is the standard choice over smooth block.

Split face vs limestone block

Limestone blocks are natural stone – quarried and cut to block dimensions, used for retaining walls, garden walls, and landscape construction throughout Perth. They offer a natural stone appearance – typically warmer and more organic in tone than split face concrete – and suit garden and landscape settings where variation in colour and surface character is a quality. Remastone’s limestone block range covers the sizes commonly used for Perth retaining and garden walls.

The choice between the two comes down to design context and structural requirements. Split face is manufactured and consistent, suited to architectural masonry where precision and colour control matter. A limestone wall carries organic variation by definition, which suits garden and landscape settings where the primary visual interest is the planting and outdoor space. Both are appropriate for retaining walls; the question is what the finished wall should look like in its setting.

Split face vs stone cladding

Stone cladding and split face block serve different functions. Stone cladding – panels of natural or manufactured stone adhered to a substrate wall – is a decorative veneer: it relies on an existing structure behind it and carries no load. Split face block functions as both the structure and the finished face simultaneously, without a secondary system layered over it.

For a new wall that needs both structural capacity and a stone-like appearance, split face block is often the more practical approach – no secondary cladding system, no adhesive, no substrate preparation requirements. For an existing wall that needs a surface finish, stone cladding applied over the face is the appropriate solution. Remastone’s stone cladding range covers natural and manufactured panel products for exterior applications. The guide to the pros and cons of stone cladding covers the comparison in more detail for projects where both approaches are viable.

Browse the full Remastone split face block range, or visit the Bibra Lake showroom to see the products and get advice on the right specification for your wall.