A brick façade consists of two materials that have to work together: the brick and the joint. The joint is deliberately the weaker part. It absorbs small movements, lets moisture and salts out of the wall and can be replaced after a few decades without the bricks having to come out. That also means the joint is the first thing to wear. If you have the wall repointed in good time, you keep the wall dry and the bricks intact; if you wait too long, you get moisture indoors and frost damage to the bricks. This article explains how you can tell that the pointing is due, what a bricklayer does during the repair and how a façade is cleaned safely.
Signs that the pointing needs replacing
Take a close look at the façade, especially on the side that gets the most driving rain, usually the south-west and west façade, and at the bottom of the wall, around window frames and under eaves and sills. Look out for:
- Weathered or sandy joints. Run a key or screwdriver through the joint with light pressure. If sand crumbles out, the binder has washed out and the joint no longer offers protection.
- Worn joints. If the joint lies deep back from the face of the brick, rainwater stays on the brick below and penetrates the wall more easily.
- Cracks in the joint, in the brick or in both. A single hairline crack in one joint is something different from a crack running across several courses; more on that below.
- Loose or broken bricks. Bricks that move, whose face is flaking off or that are cracked need replacing.
- Efflorescence: a white, powdery or crusty deposit on brick and joint. These are salts carried out of the wall with water that have crystallised on the surface. After a new wall or a wet period some efflorescence is normal; if it keeps coming back, water is structurally getting into the wall.
- Green growth of algae and moss, especially on the north side and under leaking gutters. In itself this is mainly cosmetic, but it points to a wall that stays wet for a long time.
- Damp patches indoors, such as damp spots on the inner wall after a shower of rain or mould behind cupboards against an external wall. You can read how to tell the different types of damp apart in Recognising damp and mould in your home.
Causes: why joints wear
The main cause is simply age. Wind, rain and sun slowly wash the binder out of the joint. Traditional joints often last a few decades; shorter on the weather side than on the sheltered side. Other factors include:
- Freeze-thaw cycles. Water in a porous joint or brick expands when it freezes. Each frosty spell pushes the material a little further apart.
- The wrong mortar. A joint that is harder and denser than the brick traps moisture in the brick; more on that further on. A mortar that is too weak or badly applied, on the other hand, wears too quickly.
- Leaks from gutters, downpipes, lead flashings or sills that let water run down one section of the façade.
- Settlement and movement of the foundation or the structure, causing cracks in the brickwork.
- Corrosion of cavity wall ties in the cavity wall, which causes the outer leaf to crack or bulge.
Urgent or cosmetic?
Not every defect calls for immediate action. A few worn joints on a sheltered façade or some green growth on the north side can be included in the next planned maintenance round. It is more urgent if moisture is getting in, if bricks are loose or crumbling, or if there are continuous cracks. In that case the damage increases every winter.
With cracks, look at the pattern. A stepped crack, running diagonally across several courses along the joints, often indicates settlement of the foundation or movement in the structure. Cracks that are getting wider, cracks above or below window frames that run through to the corner, and cracks that come back after repointing also call for more than pointing work. In that case, first have a structural engineer or a building surveyor establish the cause; repointing without tackling the cause only hides the problem. Horizontal cracks that recur in the joints at regular heights can indicate rusting cavity wall ties.
What the bricklayer does: raking out and repointing
Repointing is precision work. A skilled bricklayer or pointer works in this order:
- Inspection and test panel. The bricklayer assesses the brick, the existing joint and the cause of the damage. With older façades and listed buildings they often first make a small test panel to match the colour and texture of the new joint.
- Raking out or grinding out. The old joint is removed to a fixed depth, with a joint cutter, an angle grinder or by hand. The rule of thumb is a depth of at least the joint width, and in practice preferably a little deeper, so that the new joint has enough grip. The edges of the bricks must not be damaged in the process; careless grinding leaves permanently wider joints and chipped brick edges.
- Dust-free working. Grinding out joints releases fine dust containing quartz (crystalline silica). Breathing in that dust can cause silicosis and lung cancer with prolonged exposure; there is a statutory exposure limit for employees. Professionals therefore work with on-tool extraction, wet methods where possible and respiratory protection, and keep neighbours and windows out of the dust cloud. Keep windows and doors closed for as long as grinding is going on.
- Brushing out and wetting. The raked-out joints are brushed or blown free of dust and then pre-wetted. A dry brick draws the water out of the fresh mortar too quickly, so the joint does not cure properly and comes loose.
- Repointing. The new mortar is pressed into the joint in one or more layers and compacted, first the perpend (vertical) joints and then the bed joints, or the other way round, depending on the method.
- Finishing. When the mortar has stiffened just enough, the joint is given its profile and the façade is brushed clean.
- Aftercare. In sun and wind the fresh joint is protected or kept damp so that it does not dry out too quickly.
Replacing loose or broken bricks is also part of this work. The bricklayer cuts out the brick and puts back a matching one, preferably an old brick of the same type and colour, so that the repair does not stand out.
Choice of mortar: why the joint must be weaker than the brick
The mortar must be matched to the brick. Old, hand-moulded or soft-fired bricks are relatively porous and soft; in those façades, lime mortar used to be used for laying and pointing. If such a façade is repointed with a hard, dense cement joint, two problems arise. First, moisture can no longer evaporate out of the wall through the joint and finds its way out through the brick instead; there salts crystallise and water freezes, causing the edges and face of the bricks to spall. Second, a hard joint does not move with the wall, so stresses end up in the brick. The result is a crisp joint surrounded by damaged bricks, and that is harder to repair than a worn joint.
The rule is therefore: the joint must be weaker and more vapour-permeable than the brick. On older façades and listed buildings a lime-based or lime-cement mortar is often used, on modern hard bricks a standard pointing mortar. A good bricklayer can explain why they choose a particular mortar.
The joint profile also determines how the façade looks and how well water runs off. Common profiles are:
- Flush joint: level with the brick, the most common profile and good at shedding water.
- Recessed joint: a few millimetres back from the face of the brick, so the bricks stand out more. A deeply recessed joint leaves more water sitting on the brick.
- Struck or cut joint (snijvoeg): the bed joint is given a sloping or crisp cut, often seen in older façades.
- Concave joint: finished slightly hollow with a round jointing iron. With jointed-as-you-go brickwork (doorgestreken), the mortar is finished straight away during bricklaying instead of pointing later.
- Recessed bed joint: the bed joints are set back and the perpend joints are flush, which gives the façade a horizontal, layered look; widely used between the two world wars.
When repairing an existing façade, the starting point is that the profile and colour of the new joint match the original.
Weather and planning
Mortar must cure before it freezes. Bricklayers therefore do not point in frost, nor when night frost is expected in the following days; a temperature of around five degrees is often used as the lower limit. Bright sun, strong wind and driving rain on the fresh joint are also unfavourable. The pointing season therefore runs roughly from spring to autumn.
How long the work takes depends on the surface area, the accessibility and the amount of brick repair. The façade of a terraced house is often finished in a few days to a week; a whole detached house or a block of terraced houses takes several weeks. Raking out usually takes more time than the repointing itself.
Cleaning a façade: methods and risks
A façade is cleaned to remove dirt, soot, algae or efflorescence, often just before or after the pointing work. Every method also removes something from the brick or the joint; the trick is to choose the mildest method that does the job.
| Method | Suitable for | Risk |
|---|---|---|
| Cleaning with low-pressure water, possibly with a mild cleaning agent | Light dirt, algae | Little, provided the water is not sprayed into the wall |
| Steam or hot water at limited pressure | Algae, moss, grease, graffiti on sturdy brick | At too high a pressure, joints wash out and soft brick is damaged |
| Chemical cleaning with acidic or alkaline agents | Stubborn dirt, cement haze, efflorescence | Attack on brick and joint, discolouration, salts left behind if not rinsed properly; protection of glass and frames needed |
| Grit blasting or micro-blasting with a fine abrasive | Layers of paint, heavy soiling | The hard outer skin of the brick is ground away; the brick becomes more porous and gets dirty faster |
According to the Rijksdienst voor het Cultureel Erfgoed (Cultural Heritage Agency of the Netherlands), high-pressure cleaning is only suitable for hard, compact materials; on softer brick and weaker joints a pressure washer can blast the joints empty and damage the brick surface, after which the façade actually absorbs more water. With older or soft bricks, always have the façade cleaning tried out first on a small, inconspicuous test panel.
Impregnating or water-repellent treatment
After cleaning and pointing, façade companies often offer to impregnate the façade, also known as hydrophobic (water-repellent) treatment. A colourless agent soaks into the brick and makes the surface water-repellent, while water vapour can in principle still escape. Advantages: the façade absorbs less rainwater, stays cleaner and is less sensitive to frost and green growth.
There are also drawbacks and risks. Impregnation only works on a façade that is in good condition: intact pointing, no cracks, no broken bricks. Water that still gets in through a crack or a bad joint can find it harder to get out after impregnation. On façades with a lot of salts, those salts can crystallise behind the treated surface and push the face off the brick. And with rising damp from the foundation, impregnation is never the solution. The visible beading effect decreases after a number of years, but the agent sits a few millimetres deep in the brick and can no longer be removed; new pointing mortar also bonds less well to water-repellent-treated brickwork later on. So only have impregnation done once the pointing is in order and has cured, and not if there is any doubt about the cause of damp problems.
Cavity wall, cavity wall ties and insulation
From around 1920, more and more homes were built with a cavity wall: an inner leaf and an outer leaf with an air cavity between them, connected by metal cavity wall ties. Older cavity walls often used galvanised steel ties; once the zinc layer has been attacked after decades, the steel starts to rust. Rusting steel expands, pushes the joints open and can cause the outer leaf to crack or come loose. Because of the corrosion, the ties also hold the outer leaf less securely. A specialist company can locate the ties with a metal detector and establish with an endoscope, or by taking out a few bricks, whether they are affected, and if necessary replace them with stainless steel cavity wall ties fitted from the outside, with the old ties cut through or isolated.
If you are working on the façade anyway, you can also think about cavity wall insulation. This involves filling the air cavity with insulation material through small holes in the joints. That requires a façade that is watertight: bad pointing and a filled cavity are a poor combination, because water can then reach the inner leaf via the insulation material. So have the pointing put in order first. You can read what cavity wall insulation means for your energy label in Improving your energy label: which measures really count.
Listed building, protected townscape, scaffolding and VvE
If your home is a rijksmonument (national listed building), you need an omgevingsvergunning (environmental permit) for a listed-building activity for any changes. Necessary regular maintenance aimed at preserving the monumental values, such as locally repairing pointing, does not require a permit as long as the detailing, profiling, design, type of material and colour do not change (article 13.11 of the Besluit activiteiten leefomgeving, the Dutch Environment Activities Decree). According to the Rijksoverheid (Dutch central government), repointing an entire façade usually does require an environmental permit, and pointing with a different mortar, joint profile or joint colour, and drastic façade cleaning such as blasting and water-repellent treatment, may also require a permit. For municipal listed buildings and homes in a protected town or village townscape, rules in the omgevingsplan (zoning plan) may apply. If in doubt, contact the municipality in advance and choose a bricklayer with experience in restoration work.
For pointing above the ground floor, scaffolding is needed; for professionals, health and safety rules prescribe safe equipment for working at height. If the scaffolding stands on the pavement or the street, the municipality's rules apply: often a permit or notification is required, sometimes complying with municipal rules is enough; the scaffolding company usually arranges this. Scaffolding can be used straight away for other work on the façade too, such as painting, gutters or sealant work.
If you live in a flat, the façade is shared and the pointing is a matter for the vereniging van eigenaren (VvE, owners' association). It belongs in the multi-year maintenance plan. If you rent, maintenance of the façade is the landlord's responsibility. With a row of houses with several owners, it can pay to put the work out to tender together; a contractor can then fit the work of the bricklayer, scaffolder and possibly the painter into one schedule.
What belongs in the quote?
Ask for two or three quotes based on a visit to the home and check that they contain the same items:
- Surface area of the façade to be pointed in square metres, per façade.
- Raking-out depth and the method: by hand, cutting or grinding, and with what dust extraction.
- Type of mortar, joint colour and joint profile, possibly with a test panel.
- Brick repair: how many replacement bricks are included and how additional work is calculated.
- Cleaning method and any impregnation, with the product that will be used.
- Scaffolding, covering of window frames, plants and paving, and any permit for the public road.
- Waste removal and leaving the surroundings clean.
- Schedule and guarantee on the pointing.
In short: check the joints with a key every spring, have worn or sandy joints repointed before moisture gets in, have stepped or growing cracks assessed by a structural engineer first, and choose a mortar that is softer than the brick. Clean the façade with the mildest method that works and only impregnate once the pointing is in order. On VerbouwPro you post your façade job free of charge and bricklayers and contractors from your area respond.