Brick bonds and their issues: what your surveyor looks for

Some problems a surveyor finds are obvious, such as cracks in walls, slipped roof tiles or damp patches inside. Others are less obvious, and the brickwork itself is one of them. The brick pattern on the facade tells a surveyor how the walls were built, roughly how old the house is and which defects are most likely to follow. This guide explains the main brick bonds and what they reveal.

A brick bond is the pattern in which bricks are laid in a wall. Each horizontal row of bricks is called a course. Bricks are overlapped from one course to the next so that no vertical joint lines up with the joint directly above it. This brick bonding spreads the load and holds the wall together. The bond you can see on the outside of a house is usually the quickest clue to how its walls are constructed.

Most brickwork in UK homes follows one of three bonding patterns.

Stretcher bond

Every brick is laid lengthways with its long side, the stretcher, showing. Each course is staggered half a brick over the one below. A stretcher bond wall is only half a brick thick, about 100mm. That makes it the standard pattern for the outer leaf of a cavity wall, and it appears on most properties built since the Second World War.

English bond

Alternate courses of bricks laid lengthways (stretchers) and bricks laid end on (headers). English bond is one of the strongest bonds and needs a wall at least one brick thick, about 225mm in older homes. It is common in older solid walls as well as Victorian railway, industrial and public buildings.

Flemish bond

Headers and stretchers alternate along each course, with each header sitting centrally over the stretcher below. Flemish bond was widely used for the fronts of Georgian and Victorian houses because of its decorative look. The headers are sometimes picked out in darker glazed or burnt bricks to create a chequered effect. Like English bond, it usually indicates a solid wall.

Other brick bonds

Other bonds include header bond, stack bond, monk bond, herringbone and various garden wall bonds:

• Header bond shows only the ends of the bricks and is often used for curved walls.
• Monk bond is a variation of Flemish bond with two stretchers between each header.
• Herringbone is more often seen in paving and feature brickwork than in walls.
• English garden wall bond and Flemish garden wall bond use several stretchers between headers, which saves on facing bricks in boundary walls.
• Stack bond, where the joints line up vertically, has little strength on its own and is generally used for decorative panels rather than load-bearing walls.

Solid or cavity walls. Headers, the short ends of bricks, usually show that a wall is solid, with the header bricks tying the inner and outer parts of the brickwork together. A wall in stretcher bond is usually a cavity wall, with an inner and outer leaf separated by a gap and connected by metal wall ties. Most houses built before the 1920s have solid walls. Cavity walls became common from the 1930s and standard after the Second World War.

This matters because the two types of wall behave differently. Solid walls are more prone to penetrating damp and cannot have cavity wall insulation. Cavity walls bring their own risks, such as corroded wall ties.

Snapped headers. Some cavity walls are built to look like English or Flemish bond, using half bricks to mimic headers. A surveyor will look out for this so the wall is not mistaken for solid construction.

Hidden construction. Brickwork can also be just a skin. Many timber frame houses have a brick outer leaf in stretcher bond, so they look identical to a masonry building from the street.

Spalling.Spalling brick happens when water gets into the brick, freezes and expands, breaking off the face. It often points to a moisture problem, such as a leaking gutter or hard cement mortar trapping water in soft bricks.

Failing or unsuitable mortar. Eroded joints let water into the wall. Older homes were built with soft lime mortar, and repointing them with hard cement mortar can cause the bricks around it to deteriorate.

Cracking. Cracks that step diagonally along the mortar joints, particularly near doors and windows, can be a sign of movement such as subsidence. The surveyor will look at the width, pattern and likely age of any cracking.

Wall tie failure. In older cavity walls, steel wall ties can corrode and expand. This often shows as horizontal cracks in the mortar joints at regular intervals, every few courses. In more serious cases the outer leaf bulges.

Bulging solid walls. Solid walls can bow outwards where headers have failed or the wall is not properly tied in to floors and roof. This is more likely in older properties and may need restraint or rebuilding.

In a RICS Level 2 survey, the surveyor inspects the outside walls from ground level and gives the walls a condition rating, noting any defects and whether they need repair. A RICS Level 3 survey goes into more detail on the construction of the building, the likely cause of any defects and what could happen if they are left. That makes it the better choice for older solid-walled homes.

Where the surveyor suspects significant movement or wall tie failure, they may recommend a structural engineer or specialist inspection before you exchange contracts. The findings give you the grounds to renegotiate the price or agree who pays for the work.

Have you noticed something that doesn't look quite right as you've gone around the property? Your chartered surveyor will take on your specific concerns, so you're clear about what you're taking on before you commit.

Surveyor Local connects you with a nationwide panel of RICS-accredited chartered surveyors across England and Wales. Call us free on or get your instant survey quote.