If you are paying to have your brickwork repointed, you want to know it will not need doing again in ten years. The honest answer is that good repointing on a typical North London house should outlast most of the other maintenance on the building. The catch is that the lifespan depends far more on the mortar chosen and the preparation done than on the price you paid.
Repointing done properly with the right mortar should last somewhere between 30 and 60 years on a London house. The original lime pointing on many Victorian and Edwardian terraces in Haringey, Enfield, Barnet and Islington has lasted well over a century in places, so the mortar itself is not the weak link when it is matched to the brick.
Repointing that fails after 5 to 15 years is nearly always a sign of poor practice rather than bad luck. The common culprits are a hard cement mix on soft old bricks, joints that were not raked out deep enough, or work done in the wrong weather. When you see mortar popping out or bricks spalling on a house that was pointed within living memory, one of those three is usually to blame.
Most of the older housing stock in North London is soft London stock brick laid in lime mortar. If a pointer uses a strong sand and cement mix on those walls, the mortar ends up harder than the brick. Moisture then escapes through the brick face instead of the joint, and the brick freezes and flakes in winter. The pointing may look fine for a decade while the bricks around it slowly fail.
Depth matters as much as the mix. The old mortar should be raked out to at least twice the joint width, so typically 15 to 25 mm on a standard 10 mm joint. A skim of new mortar smeared over a joint that was barely raked out will crack and fall away within a few years, and you will see it happen first on the exposed elevations facing the prevailing weather.
London stock bricks are porous and were made to breathe. They were laid with lime mortar precisely because it flexes slightly with the building and lets damp out. A lime based repoint, either a natural hydraulic lime such as NHL 3.5 or a hot lime mix on older properties, keeps that balance and is the reason some work lasts 50 years or more.
Later houses from the 1930s onwards, including many semis in Southgate, Finchley and Edmonton, often used harder machine made bricks and were sometimes built with cement mortar from the start. On those, a weaker cement lime mix is usually appropriate. The point is that the mortar should always be softer than the brick, and a tradesperson who cannot tell you which mix they are using and why is a warning sign.
London's weather is not especially harsh, but the freeze thaw cycles between November and March are exactly what pull weak mortar out of joints. Chimney stacks, parapets and the top few courses under a gutter take the worst of it and are usually where repointing fails first, sometimes years before the rest of the wall.
Run a key or a screwdriver along a joint. If it crumbles out easily or is recessed more than 5 mm behind the brick face, that section is due. Look for mortar that has cracked away from the brick edge leaving a fine gap, or for green staining and damp patches inside that line up with the outside wall.
Not every wall needs full repointing. On many properties only the front elevation, the chimney or the parapet wall is failing while the rest is sound. A decent pointer will tell you which areas to leave alone, and a partial job done well will last as long as a full one.
Ask what mortar they intend to use and why it suits your brick. Ask how deep they rake out and whether they do it by hand or with a grinder, because grinders can widen and damage joints on old brickwork if used carelessly. Ask what they do about weather and curing, and whether they protect fresh lime work from sun and frost.
On cost, repointing in London typically runs from roughly £40 to £80 per square metre depending on access, joint condition and whether lime is specified, with scaffolding on top for anything above ground floor. A quote that is far below that range for a lime repoint is often a sign the preparation will be skipped, and that is where the longevity goes.
On pre 1920s brick it usually lasts longer, not the same, because it does not damage the surrounding bricks. On harder modern brick a weaker cement lime mix is fine and lime is not always necessary.
No. Failure that early almost always points to shallow raking out, the wrong mortar or poor curing. It is worth getting a second opinion before paying for the same job again.
Rarely. Chimneys, parapets and the weather facing elevation usually go first, and repointing just those areas is a normal and sensible approach if the rest is sound.
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