Block types in Saudi Arabia: choosing between concrete, insulated and red block for your villa

Choosing a block type can feel minor next to foundations and the concrete frame, but it decides how your villa's walls handle Riyadh heat, how hard the air conditioning works, and how good the plaster and finishes will look later. This guide covers the block types you will meet in Saudi Arabia, compares them side by side, and lists what to check on site before the walls disappear under plaster.

What blockwork actually does in a villa

In most modern Riyadh villas the walls do not carry the building. Loads travel through columns and beams to the foundations, which are built during the skeleton stage (the reinforced concrete frame, known locally as adhm). Block walls then do four other jobs:

• Separate inside from outside, keeping out heat, dust and noise.
• Divide the interior into rooms, corridors and bathrooms.
• Carry electrical and plumbing runs inside them.
• Provide the surface for plaster, then paint or tiles.

So the useful question is not "which block is strongest?" but "which block suits this particular wall?" A west-facing external wall, a partition between two bedrooms and a course sitting on the soil have very different needs.

Concrete block: hollow and solid

Concrete block, made from cement, sand and fine aggregate pressed in moulds and water-cured, is by far the most common walling unit in the Kingdom.

Hollow concrete block

The cores make it lighter and use less material. In villas you will usually see:

• 200 mm block for external walls.
• 150 mm or 100 mm block for internal partitions, as the drawings specify.

It is easy to source, economical, quick to lay and every mason knows it. The weakness is limited thermal resistance: used alone on external walls, it lets summer heat through quite readily.

Solid concrete block

Few or no cores, heavier, and more resistant to impact and moisture. Typical uses:

• The first courses on or below ground level.
• Walls around water tanks and pump rooms.
• Parts of boundary walls, depending on the design.
• Spots where the engineer wants extra strength or fixing capacity.

Insulated (thermal) block

Insulated block is a concrete block with an insulating insert, usually polystyrene, that interrupts the path of heat from the outer face to the inner face. On west and south walls that bake for hours in a Riyadh summer, the difference in comfort and electricity use is real.

Why it is usually chosen for external walls:

• It reduces heat gain and the cooling load.
• It helps the building envelope meet the energy-efficiency requirements of the Saudi Building Code, which the designer sets out in the drawings.
• It is laid much like standard block, so no specialist crew is needed.

Workmanship still matters. Big gaps in the mortar, or exposed concrete columns and beams left untreated in the external wall, let heat bypass the insulation. Those concrete elements conduct more heat than the block around them, which is why designers sometimes call for extra treatment there.

Red clay block

Red block is fired clay with many small cells, and it has become more popular in villa projects for good reasons:

• Lighter than an equivalent concrete block, reducing load on the frame.
• Good thermal and acoustic performance.
• Consistent dimensions, which help produce true walls when laid carefully.

The trade-offs:

• Higher relative cost than standard concrete block.
• More fragile in transport and handling, so breakage on site can climb if storage is careless.
• Needs skilled masons, since cutting and chasing for services requires proper tools to avoid cracking.
• Heavy wall-hung items such as cabinets or water heaters may need fixings designed for hollow masonry.

Side-by-side comparison

Treat this as a guide. The final choice follows the drawings and the designer's specification, and balances upfront cost against energy savings over the years you live in the house.

Matching block to each part of the villa

Rather than picking one block for the whole building, group the walls:

1. External walls: insulated or red block, especially on west and south elevations.
2. Internal partitions: hollow concrete block at the thickness on the drawings, perhaps thicker between bedrooms if sound matters to you.
3. Low courses and damp areas: solid block with suitable damp-proofing.
4. Bathroom and kitchen walls: plenty of chasing for pipes, so choose a block that cuts cleanly.
5. Boundary walls: set by height and design; see Boundary Walls & Water Tanks.

How a good wall is built

The block is half the story; the other half is laying it. On site, look for:

• Inspected deliveries: intact edges, even sizes, no crumbling surfaces, properly cured units.
• Damp concrete block in hot weather, so it does not draw water out of the mortar too fast.
• Consistent mortar, mixed in batches that are used before they start to set.
• Staggered vertical joints, the half-block bond, never stacked one above another.
• Level courses and plumb walls, checked with line and level as work goes up.
• Ties into columns at regular intervals so the wall does not separate from the frame.
• Lintels over every door and window, bearing on both sides of the opening.
• No rushing to full height in a single day, and the last gap under the beam closed carefully later.
• Water spraying for the first few days, chases cut with a saw rather than hacked, and mesh over block-to-concrete joints before plaster.

All of this shows up again in the plaster. Our plastering quality checklist covers what to inspect at that stage.

Common mistakes

• Choosing external block on price alone, then paying in higher electricity bills for years.
• Mixing block types within one wall without an engineering reason, inviting cracks along the junction.
• Skipping column ties, which leaves a straight vertical crack where wall meets column a few months later.
• Packing the gap under the beam immediately with weak mortar, leading to a horizontal crack at the top of the wall.

How Marafi handles blockwork

We start blockwork once the frame is complete and the architectural drawings have been reviewed with the owner. We propose a block type for each group of walls and explain the effect of each option on insulation and relative cost in a transparent, itemised quotation. We use approved materials, follow the engineering drawings strictly for wall thicknesses and openings, and our supervisors and engineers check course levels, plumb and column ties throughout, to the highest safety standards on site.

Owners receive photos at each key stage so they see the walls before they are covered. Service details are on Blockwork & Masonry, the next stage on Plastering, and the full sequence on How we build. For where blockwork sits in the overall project, read villa construction stages in Riyadh.

Quick checklist before you approve a block type

• Choose block per group of walls, not one type for the whole villa.
• Prefer insulated or red block for sun-exposed external walls.
• Use solid block for ground-contact courses and around tanks.
• Inspect deliveries and reject broken or crumbling units.
• Watch levels, plumb, column ties and lintels as walls go up.
• Do not allow plaster until walls are reviewed and junction mesh is fixed.

Getting ready for blockwork, or want to compare options on your own drawings? Contact us to arrange a site visit, and we will send an itemised quotation showing the block specified for each wall.

Frequently asked questions