RC Frame vs Masonry: Choosing the Right Structure for Multi-Storey Buildings

Below four storeys, load-bearing masonry is often the most economical structural choice. Above eight storeys, it isn't viable at all. Between these limits sits the architectural and commercial fight between RC frame and masonry — a fight that's quietly being re-shaped by sustainability requirements and labour economics.

Definitions

• RC (reinforced concrete) frame: Columns and beams cast from steel-reinforced concrete carry all vertical and lateral load; walls are non-load-bearing infill.
• Load-bearing masonry: Walls of brick, block, or stone carry the building loads directly; floor structure spans wall-to-wall.

Height limits

Load-bearing masonry

• Typical: Up to 4–5 storeys
• Maximum economic: 6 storeys with engineered solutions
• Beyond: Possible but rarely economic — wall thicknesses become impractical

RC frame

• Routinely 4–25 storeys
• 50+ storeys feasible with engineered core and column systems

Below 5 storeys, the choice is open. Above 6, RC frame (or steel) dominates.

Cost

Indicative South African rates for the structural shell (2026, including foundations within typical depth):

• Load-bearing masonry, 3-storey: R3,600 – R5,400 per m² GIFA
• RC frame, 3-storey: R4,400 – R6,400 per m² GIFA
• RC frame, 6-storey: R5,200 – R7,200 per m² GIFA
• RC frame, 12-storey: R6,400 – R9,000 per m² GIFA

Masonry tends to win on price up to four storeys. RC scales better and gets relatively cheaper per m² as height increases.

Programme

Load-bearing masonry is sequential — walls and floors are built storey by storey, with curing time on mortars. RC frame can sequence more efficiently with formwork systems but introduces concrete curing windows.

• 4-storey masonry: 24–30 weeks shell
• 4-storey RC frame: 18–24 weeks shell
• RC with jump-form core and pre-cast floors: 1 storey per week typical

Acoustic performance

Masonry wins comfortably for between-flat and inter-tenancy walls — mass is the cheapest acoustic strategy. RC frames need detailed treatment of partition walls to match. For residential mid-rise, this is one of the strongest arguments for masonry up to its height limit.

Fire performance

Both materials are inherently fire-resistant. Masonry walls of normal thickness achieve 90–120 minutes; concrete columns and slabs achieve similar without intervention. Steel structures, by contrast, require protective coatings to match.

Thermal mass

RC frames with exposed soffits offer significant thermal mass, useful for passive cooling strategies. Masonry walls contribute thermal mass to inner zones. Both outperform timber and lightweight steel in summer overheating mitigation.

Future flexibility

RC frame wins for adaptability — non-load-bearing partitions can be reconfigured without structural intervention. Load-bearing masonry locks the floor plan permanently; subdividing rooms is straightforward, but combining them is structurally expensive.

Sustainability

Both materials carry significant embodied carbon. Mitigation strategies differ:

• Masonry: Specify low-carbon mortars (lime-cement blends), high-recycled-content blocks, and locally sourced brick
• RC frame: Specify GGBS or PFA cement replacement (50–70% replacement is achievable), recycled aggregate, post-tensioned slabs to reduce volume

A well-specified RC frame with 65% GGBS cement can have a lower embodied carbon footprint than poorly specified masonry. Specification matters more than material choice.

Decision framework

Choose load-bearing masonry when:

• Building is 1–4 storeys
• Floor plan is regular and won't change
• Acoustic isolation between units is critical (residential, hotels)
• Local trade labour favours masonry over concrete
• Programme can absorb sequential construction

Choose RC frame when:

• Building is 5+ storeys
• Future flexibility is important (office, retail, mixed-use)
• Open-plan ground floors with smaller floors above
• Long-span requirements at any level
• Seismic or wind loading is significant

Hybrid systems

Many South African mid-rise residential schemes use a hybrid: load-bearing masonry external and party walls with RC slabs spanning between them. Combines the acoustic and cost benefits of masonry with the spanning efficiency and crisp finishes of RC slabs.

MCFAR engineers RC, masonry, and hybrid structures across South African projects. Send us your scheme for a structural option study.

Frequently Asked Questions