When extending a property, the goal is rarely to create contrast. Instead, most homeowners aim for visual continuity. However, this is easier said than done. Even bricks that appear identical at first glance can differ once installed.
Bricks vary due to:
- Clay composition
- Manufacturing process
- Firing temperature
- Age and weather exposure
Older bricks often develop a patina over time due to environmental factors such as rain, UV exposure, and pollution. This means that even if you source the same type of brick, the new ones may still appear too clean or vibrant compared to the original structure.
A mismatch in brickwork can:
- Reduce kerb appeal
- Make the extension look detached
- Affect perceived property value
Key Factors That Affect Blending
1. Brick Colour
Colour is the most noticeable factor when comparing old and new brickwork. Even slight tonal differences become obvious when bricks are placed side by side.
Important considerations:
- Natural light changes perception of colour
- Bricks often have multiple tones, not a single shade
- Weathered bricks appear softer and less saturated
Viewing samples outdoors and at different times of day is essential, as lighting can significantly alter appearance
2. Brick Texture
Texture plays a critical role in how light reflects off the surface. A smooth modern brick will stand out against a rough, handmade older brick.
Common textures:
- Smooth (machine-made)
- Wire-cut
- Handmade or tumbled
Matching texture ensures consistency in how the wall visually behaves under light conditions.
3. Brick Size and Shape
Older UK homes may use imperial-sized bricks, while modern bricks are typically metric. Even small differences in size can disrupt alignment and bonding patterns.
To maintain consistency:
- Match brick dimensions precisely
- Ensure coursing lines align
- Avoid uneven joint thickness
4. Mortar Colour and Style
Mortar is often overlooked, but it accounts for approximately 15–20% of the visible wall surface
This makes it just as important as the bricks themselves.
Mortar Influences:
- Colour (grey, buff, white, red tones)
- Sand type and grain size
- Joint profile (flush, recessed, weather-struck)
Poor mortar matching can make even perfectly matched bricks look wrong.
Mortar Comparison Table
| Feature | Poor Match | Good Match |
|---|---|---|
| Colour | Too dark/light | Closely matches aged tone |
| Texture | Smooth vs grainy mismatch | Similar aggregate |
| Joint Style | Different profile | Consistent with existing |
| Visual Impact | Extension stands out | Seamless integration |
Techniques to Blend Extension Bricks
1. Source Matching or Reclaimed Bricks
The best approach is always to find bricks that closely match the original.
Options include:
- Salvage yards
- Manufacturers still producing similar styles
- Bricks taken from hidden areas of the property
Reclaimed bricks are particularly effective because they already have weathering.
2. Use Brick Blending
Instead of relying on a single brick type, mixing multiple similar bricks can create a natural variation.
Benefits:
- Mimics natural ageing
- Reduces obvious colour differences
- Creates a more authentic finish
3. Brick Tinting
When a perfect match isn’t possible, brick tinting is a highly effective solution.
This process:
- Adjusts the colour of new bricks
- Uses mineral-based stains
- Allows bricks to weather naturally
It is especially useful where new brickwork looks too fresh compared to older walls
4. Weathering Techniques
New bricks often need to be toned down to match older ones.
Methods include:
- Natural weather exposure over time
- Light staining or limewashing
- Surface treatments to reduce brightness
These techniques help soften the contrast between old and new materials.
5. Matching the Brick Bond
Brick bond refers to the pattern in which bricks are laid.
Common UK bonds:
- Stretcher bond
- Flemish bond
- English bond
Ensuring the extension follows the same bond pattern is essential. Disruption in the pattern makes the join highly visible.
6. Tooth-in Brickwork
“Toothing in” involves removing sections of existing brickwork so new bricks can interlock with old ones.
Advantages:
- Eliminates straight vertical joins
- Creates a natural transition
- Improves structural integration
This technique requires skill but significantly improves visual blending.
Mortar Matching in Detail
Mortar matching is often more complex than brick matching.
Key Variables
| Element | Impact on Appearance |
|---|---|
| Sand Colour | Primary determinant of mortar colour |
| Cement/Lime Ratio | Affects tone and strength |
| Additives | Fine-tune colour |
| Ageing | Changes appearance over time |
Sand is particularly important, as different sands can produce dramatically different colours even with the same mix
Matching Weathered Mortar
One common mistake is matching new mortar to what the old mortar looked like originally rather than how it looks today.
Best practice:
- Match the current weathered appearance
- Slightly lighten mixes to account for curing
- Test samples before full application
Planning and Testing
Before committing to materials, testing is essential.
Sample Testing Checklist
| Step | Action |
|---|---|
| 1 | Obtain multiple brick samples |
| 2 | Compare against existing wall |
| 3 | View in different lighting conditions |
| 4 | Test mortar mixes |
| 5 | Build a small sample panel |
This process helps avoid costly mistakes during construction.
Cost Considerations (UK)
Blending bricks effectively may increase costs, but it adds significant value.
Typical Costs
| Item | Estimated Cost (GBP) |
|---|---|
| Standard bricks (per 1,000) | £250 – £400 |
| Handmade/reclaimed bricks | £600+ |
| Brick tinting | £40 (DIY kits) to £500+ (professional) |
| Mortar matching | £200 – £800 |
Higher upfront costs often result in better long-term value due to improved aesthetics and property appeal.
Common Mistakes to Avoid
1. Ignoring Mortar
Many focus only on bricks, but mismatched mortar can ruin the overall look.
2. Choosing the Closest Match Too Quickly
Even small differences become obvious after installation.
3. Not Considering Weathering
New bricks will always look fresher unless treated or aged.
4. Poor Workmanship
Even perfectly matched materials will fail if laid incorrectly.
5. Straight Joint Lines
Visible vertical joins make extensions obvious.
Professional vs DIY Approach
DIY
Suitable for:
- Small projects
- Minor repairs
Challenges:
- Achieving accurate colour match
- Limited access to materials
Professional Services
Advantages:
- Access to wider brick databases
- Expert mortar matching
- Advanced techniques like tinting
This is particularly beneficial for visible extensions or period properties.
Blending Modern Extensions with Older Homes
In some cases, perfect matching is not possible or even desirable.
Alternative approach:
- Use complementary bricks
- Maintain similar tones and textures
- Create a “sympathetic contrast”
This can result in a modern yet cohesive design.
Timeline of Visual Blending
| Stage | Appearance |
|---|---|
| Immediately after build | Obvious contrast |
| 3–6 months | Slight blending begins |
| 1–2 years | Weathering reduces differences |
| 5+ years | Often difficult to distinguish |
Natural ageing plays a significant role in achieving a seamless finish over time.
Final Thoughts on Achieving a Seamless Finish
Blending extension bricks with an existing house is both a technical and visual challenge. It requires careful planning, material selection, and skilled execution. By focusing on key factors such as brick colour, texture, mortar, and bonding techniques, it is possible to create an extension that feels like a natural continuation of the original structure.
Attention to detail at every stage—from sourcing materials to final finishing—ensures that the extension enhances rather than detracts from the character of the home.