How to Match Bricks for an Extension: UK Facing Brick Guide

How to Match Bricks for an Extension

Matching bricks for an extension is one of the most visible material decisions in a building project. A brick can look close when viewed individually but become obviously different once several square metres are laid beside the original house. The best results come from matching brick size, colour blend, texture, manufacturing character, mortar and joint profile rather than searching for a colour name alone.

This UK guide gives you a practical process for narrowing down the right facing bricks for an extension, porch, garage conversion or repair. It also explains when an exact match may be unrealistic and how to create a deliberate complementary finish instead.

Why Brick Matching Is Difficult

Existing brickwork changes over time. Weathering, dirt, lichen, pollution, previous cleaning and differences in exposure all affect appearance. The brick you see on a 30-year-old wall may look quite different from the same product when new. Some original ranges have also been discontinued or changed.

That means 'find the same red brick' is rarely enough. A convincing match usually requires comparing several characteristics together and viewing candidates against the actual building.

Step 1: Measure the Existing Bricks

Start with dimensions. Measure the length and height of several bricks, not just one, and note the mortar-joint thickness. Many modern UK facing bricks are around 215 x 102.5 x 65mm, but older buildings and some contemporary products use different formats, including 73mm heights.

Coursing is critical. If the new brick is even a few millimetres taller, the difference accumulates over multiple courses and can make window heads, sills and roof lines difficult to align. Our UK facing brick sizes guide explains how size affects course calculations.

Step 2: Identify the Main Colour and Secondary Tones

Stand several metres back from the wall and identify the overall colour. Then move closer and note secondary tones. A wall described as red might include orange, brown, purple, black or pale flashes. A buff wall may contain cream, grey and yellow variation.

Look for the proportion of each tone, not just whether a candidate brick contains them. A new brick with 50% dark tones will not match an old wall where dark bricks appear only occasionally.

Step 3: Compare Texture

Texture can make two similarly coloured bricks look completely different. Identify whether the existing wall is smooth, wirecut, dragfaced, rusticated, sanded, creased, stock-like, handmade or waterstruck in appearance. Check the edge profile too: crisp squared edges read differently from soft, irregular edges.

Run your eye across the wall in side light. Shadows reveal texture more clearly than flat front-on photographs.

Step 4: Look at the Brick Manufacturing Style

Manufacturing process often explains the visual character. Wirecut bricks usually have more defined edges and can show perforations. Soft-mud or stock bricks can have softer shapes and more traditional variation. Handmade-style and waterstruck bricks have their own surface characteristics.

Understanding the type helps narrow the search quickly. Read our guide to wirecut, stock, handmade and waterstruck bricks if you are unsure what you are looking at.

Step 5: Check the Mortar

Mortar is one of the biggest reasons a new extension can look mismatched even when the brick is close. Record the existing mortar colour, joint thickness and joint profile. Is it pale cream, buff, natural grey or dark grey? Is the joint flush, recessed, weather-struck or bucket-handle?

Fresh mortar also dries and weathers, so a newly completed extension may initially appear different. The goal is to select a compatible mortar system and a colour that settles toward the intended final appearance. See our brick and mortar colour guide.

Step 6: Check Brick Bond

Most modern cavity-wall façades use stretcher bond, but older properties may use Flemish bond, English bond or variations. Matching the bond affects both appearance and quantity. If the extension changes bond unexpectedly, the join between new and old masonry can become more noticeable.

Step 7: Inspect the Existing Brick in Different Areas

Do not take your reference from one damp corner or heavily weathered elevation. Compare protected areas under eaves, exposed walls and sections near ground level. This helps distinguish the brick's original colour from later staining or weathering.

Where safe and practical, an unused original brick from a loft, garage or previous alteration can be an excellent physical reference.

Step 8: Shortlist Several Candidate Bricks

Use manufacturer ranges and merchant filters to build a shortlist. JJ Building Materials stocks large ranges from Forterra, Ibstock and Wienerberger. Start by matching size and broad colour, then narrow by texture and tone. A live example such as the Forterra Atherstone Red facing brick demonstrates why an exact product should be viewed as a full blend rather than by name alone.

Step 9: Compare Samples at the Property

Product photography is helpful for discovery but cannot reproduce every screen, lighting condition or batch. View physical samples beside the existing wall in natural daylight where possible. Look from close up and from the distance at which the extension will normally be seen.

If choosing between two candidates, arrange several bricks together rather than comparing single units. The blend across a small panel gives a better indication of the final wall.

Step 10: Consider a Sample Panel

For a large or high-value project, a sample panel combining the proposed brick, mortar colour, joint profile and bond is one of the best ways to assess a match. It also gives the client, builder and designer a common reference for workmanship.

What if the Original Brick Is Discontinued?

A discontinued brick does not mean the extension has to look wrong. Manufacturers may have current ranges with similar colour and texture, and specialist brick-matching services can help identify alternatives. The aim can be a close blend rather than an identical product code.

On some homes, a deliberately complementary brick can look better than an almost-but-not-quite match. This is particularly true when the extension is architecturally distinct.

Matching Red Bricks

Red brick matching requires careful attention to undertone. Warm orange-reds, dark reds, purple reds and weathered multi-reds can all appear under the same basic category. Also compare whether the face is smooth or textured and how dark headers or flashes are distributed.

Matching Buff and Yellow Bricks

Buff and yellow bricks can vary from pale cream to deep golden or brown-toned blends. Mortar colour has a particularly strong effect on these lighter bricks. A dark grey joint may make the new wall look very different from an existing pale-mortar façade even if the bricks are close.

Matching Grey and Contemporary Bricks

Grey bricks often have cooler blue-grey, warm greige or charcoal undertones. Match them in daylight beside windows, cladding and render. Smooth grey bricks can be unforgiving of colour differences, so sample assessment is useful.

Should You Clean the Old Brickwork First?

Cleaning can alter the appearance of existing masonry and may damage brick or mortar if the wrong method is used. Do not aggressively clean an old wall simply to force a colour match. If cleaning is part of the renovation, use a method suitable for the brickwork and ideally assess the expected final appearance before choosing the new brick.

Blending New Facing Bricks During Laying

Even within one product, fired clay bricks show natural variation. Rather than laying one pack completely and then moving to the next, blend from several packs where manufacturer guidance recommends it. This distributes minor shade differences across the elevation and prevents obvious bands.

How Many Bricks Should You Order?

Calculate the extension's net wall area, subtract large openings and add returns, piers and waste. Around 60 standard 65mm bricks per m² is a familiar preliminary figure for a half-brick wall face with typical joints, but use the actual product dimensions and bond.

Order the project quantity together where possible. A later top-up may come from a different production batch and can make colour matching harder.

When to Use a Contrasting Brick Instead

If no close match exists, a deliberate contrast can be more successful than a weak imitation. For example, a clearly contemporary extension might use a dark grey or complementary multi brick while retaining alignment, proportions and detail quality. This is a design decision and may need planning or architectural approval depending on the project.

Brick Matching Checklist

• Measure brick length, height and mortar courses.
• Identify dominant and secondary colours.
• Match surface texture and edge shape.
• Identify likely manufacturing style.
• Record mortar colour and joint profile.
• Check the existing bond.
• View samples against the wall in daylight.
• Build a sample panel where appearance is critical.
• Order enough from a consistent supply.
• Blend packs during laying.

Brick Matching FAQs

Can you perfectly match old bricks?

Sometimes, but not always. Weathering and discontinued ranges can make an exact visual match difficult. A carefully selected close match can still produce an excellent result.

How do I find out what brick my house has?

Start with dimensions, colour and texture. Manufacturer or specialist brick-matching services may help identify a current or historic product.

Does mortar matter when matching an extension?

Yes. Mortar colour, joint thickness and joint profile can make a major difference to how well new brickwork blends with old.

Should new bricks look darker at first?

They can look different because old brickwork has weathered and new mortar is fresh. The final comparison should allow for normal drying and weathering.

Can I mix two brick types to improve a match?

Purposeful blending can sometimes help reproduce a varied existing wall, but it should be designed and sampled carefully so the result looks natural.

What size are most UK house bricks?

Around 215 x 102.5 x 65mm is common, but many older and specialist bricks differ.

Where can I compare bricks for an extension?

Browse JJ Building Materials' facing bricks by manufacturer, colour and product style.

Should I buy all bricks at once?

Where possible, yes. Ordering the full quantity together helps reduce the risk of noticeable batch differences later.

Final Advice

The best brick match is rarely achieved by colour alone. Measure first, compare texture and manufacturing style, match the mortar, view samples at the building and think about the wall as a complete surface. Those steps make it far more likely that a new extension will feel integrated with the original property.