Mortar joints protect the edges of bricks and help keep rain from entering a wall. Over time, weathering, movement, or unsuitable previous repairs can cause mortar to deteriorate. Look for changes across the wall rather than judging one small patch in isolation. Crumbling joints, visible gaps, and damp inside can all warrant closer attention. This guide explains what to check safely, what signs may have other causes, and when to arrange a professional assessment.
Check for crumbling mortar
Inspect the mortar joints from ground level in good light. Failing mortar may look powdery, flake away, or break apart easily. You might also notice loose fragments at the base of the wall. A light visual check is enough; avoid scraping joints with tools, which can damage sound mortar and make it harder to assess the original condition.
Look at several areas, including sheltered sections and places exposed to wind-driven rain. Deterioration may be uneven, so one damaged joint does not automatically mean the whole wall needs repointing. Note where the mortar is affected and whether the surrounding bricks appear sound. Photos taken from the same position over time can help show whether the damage is spreading.
Look for gaps and recesses
Open joints, missing mortar, or joints that have worn noticeably back from the brick faces can leave the wall more exposed to water. Pay particular attention around corners, window and door openings, and the junctions between walls. These areas can be vulnerable, but gaps may also relate to movement or a failed seal rather than ordinary mortar wear.
Do not fill a gap with a hard repair product or sealant before identifying its cause. A mismatched mortar can harm brick edges, while sealing a damp wall can limit drying. If a crack is widening, runs through bricks as well as joints, or appears alongside bulging or displacement, arrange a professional inspection promptly.
Notice signs of water ingress
Inside the building, watch for damp patches, peeling finishes, or a persistent musty smell on walls beside exposed brickwork. Outside, look for staining, moss growth, or mortar that stays wet long after nearby areas have dried. These signs can point to water entering through defective joints, but they can also come from leaking gutters, roof details, plumbing, or condensation.
Check the surrounding details as well as the mortar. A blocked gutter, leaking downpipe, damaged sill, or poor drainage can send water onto a wall and make joints deteriorate faster. Record where and when damp appears, especially after rain. Addressing the water source matters; repointing alone may not solve a leak caused by another building defect.
Know when to call a professional
Arrange an assessment when mortar is visibly missing across several areas, continues to crumble, or is accompanied by recurring damp. A contractor can check the extent of deterioration, look for other sources of moisture, and assess whether the bricks can be repointed without further damage. If you see loose masonry, a bulging wall, or a large or rapidly changing crack, seek advice promptly and keep people away from the affected area.
Ask the contractor to explain which areas need work and why, how they will match the mortar to the existing brickwork, and whether repairs to gutters or other details should come first. Repointing should remove defective mortar carefully and use a compatible replacement. For older or unusual brickwork, matching the mortar’s properties and appearance is especially important to avoid damaging the masonry.
Crumbling mortar, open joints, and recurring damp are useful warning signs, but they do not all point to the same cause. Note what you see, check nearby drainage and rainwater goods, and arrange an assessment if deterioration is widespread or moisture persists. Leeds Brickworks can discuss brick restoration options and help you decide on a suitable next step.