Important General Technical Information

Efflorescence in Concrete Products

Efflorescence is a temporary and naturally occurring phenomenon associated with Ordinary Portland Cement (OPC), commonly used in the manufacture of concrete products. It manifests as white patches or a general lightening of the concrete surface, often mistaken for fading or discoloration.

This effect results from soluble salts migrating to the surface through capillary action and crystallizing upon contact with air. While its appearance may raise aesthetic concerns, efflorescence is entirely superficial and does not compromise the strength, durability, or long-term performance of the concrete product.

In most cases, natural weathering, such as rain and wind exposure is sufficient to gradually remove efflorescence from the surface. As such, it is advisable to allow an initial period of weathering before evaluating the final appearance of the product.

Please note that the occurrence of efflorescence is beyond the manufacturer's control and, as such, responsibility for its appearance cannot be accepted.

Weathering and Site Conditions

Natural weathering and site-specific conditions may occasionally result in variations in the appearance of stone products. Differential weathering can lead to patchy or dark surface discolouration on individual units. These effects are typically cosmetic, diminish over time, and do not impact the long-term performance of the material.

Due to the inherent properties of natural stone, additional markings, mineral deposits, or patches may form over time as the stone's mineral content oxidises.

All stone products are susceptible to algae and organic growth under certain environmental conditions and may require periodic cleaning. Discolouration may also occur in areas adjacent to plant pots, borders, or trees due to the transfer of organic material. In such cases, specialist maintenance guidance may be necessary.

Maintenance

Paving materials require periodic cleaning to maintain their appearance. Regular sweeping to prevent the build-up of detritus which can detract from the surface’s look and contribute to wear over time is recommended.

Light coloured blocks will naturally emphasise muddy footprints, general stains, such as tyre marks and oil spills on a driveway.  As a result, these surfaces will typically require more frequent maintenance to preserve their overall appearance.

Proprietary cleaning agents are widely available. However, care should be taken when buying cleaning agents as some varieties contain a concentration of acid, which can adversely affect the appearance of concrete and natural stone products.

A trial on a small section of paving is always recommended prior to using it on the full area.

For general cleaning of dirt and algae, vigorous brushing with a stiff yard broom with plenty of hot detergent solution (washing up liquid or non-bio washing powder), thoroughly rinsed with clean water should suffice. Repeated treatment may be required for paved areas sited beneath trees or in permanent/near permanent shade. In certain circumstances, prolonged contact with wet leaves can result in staining of the paved area. Such contact should be avoided wherever practical. Further information can be found on relevant websites.

Power-Washing Guidelines for Paving Maintenance

High-pressure power-washing is generally not required for regular maintenance. However, if power-washing methods are to be employed, it is essential to follow the precautions below to avoid damaging the paving surface:

High-pressure power-washing is generally not required for regular maintenance. However, if power-washing methods are to be employed, it is essential to follow the precautions below to avoid damaging the paving surface:

1.     Pre-Cleaning Preparation
Thoroughly sweep the area to remove all detritus (loose debris) that could act as an abrasive when displaced by the high-pressure jet.

2.     Trial Testing
Always conduct a trial on a small, inconspicuous area before proceeding with large-scale power-washing.

3.     Pressure Settings
Use no more than medium pressure to clean the paving. Excessive force can damage the surface and joints.

4.     Lance Positioning
Hold the power-washing lance at an oblique angle, maintaining a minimum distance of 200mm (8 inches) from the paving surface to prevent erosion or damage.

5.     Joint Care
If jointing sand is removed during washing, it is critical to re-sand the joints using similar materials to preserve structural stability.

6.     Mortar Joint Repair
If mortar joints are loosened or damaged, ensure they are re-pointed or repaired promptly to maintain the paving’s integrity and appearance.

For further information and detailed care instructions, please visit our website and download the Marshalls Cleaning & Maintenance Guide.

Suitability & Application

The paving flags featured in this brochure/Webpage are primarily designed for domestic and landscape applications.

For areas subject to intense foot traffic—such as pedestrian precincts or commercial spaces—please refer to our separate literature specifically tailored for commercial use. This information can be obtained by contacting our Group Technical Services Team.

In areas that experience vehicular overrun (e.g. driveways or parking spaces), we recommend using products from our driveways range, as outlined in the Driveways section of this brochure. These products are suitable for pedestrian and light vehicle use.

For pavements exposed to frequent heavy vehicle traffic, we advise selecting block paving from our commercial/specification range. These products are described in separate literature, available upon request.

If you are unsure about the suitability of any Marshalls product for your specific project, please contact our Group Technical Services team for free expert advice.

Colour Variation

The colours shown in this literature are as accurate as photographic and printing processes allow. However, we strongly recommend that final colour choices be made using actual product samples, which can be requested via our website.

Please note that while every effort is made to ensure consistent colour across our products, slight variations between production batches may occur. To achieve a uniform appearance, particularly for larger projects, we advise that all materials be ordered from the same production batch.

Additionally, for best results on site, products should be thoroughly mixed during installation by drawing from at least three different packs simultaneously.

Batch Variation - Concrete Products

Marshalls concrete products are manufactured using naturally occurring raw materials. As a result, slight variations in colour and appearance may occur between batches—even when the same product is used. Despite employing high-quality materials, advanced manufacturing processes, and stringent quality control, batch-to-batch variation is a natural occurrence.

Although typically minor, these differences may be noticeable if products from separate batches are installed side by side. To reduce the risk of visible variation, we strongly recommend checking batch codes before installation and ensuring that all packs used in a continuous area come from the same production batch.

Each batch label includes a product code. The first two letters identify the manufacturing location, and the week number indicates the production date within the year.

Batch Variation - Porcelain Products

During porcelain tile production, colour variation can occur. To maintain consistency, Marshalls sources only first-choice tiles—selected from a narrower colour spectrum to ensure uniformity across each range.

We aim to dispatch all porcelain orders from the same batch, with the batch code clearly printed on each pack (usually denoted by a letter followed by a number). Please confirm all packs share the same batch code prior to installation.

For porcelain ranges available in multiple sizes, we do not recommend mixing sizes, even when batch codes match, as products may be manufactured at different sites.

If in doubt, please consult our Group Technical Services Team for guidance.

Natural Stone

Natural stone products inherently display variation in colour, texture, and surface markings due to their geological origin. These characteristics are part of the stone’s appeal and should be expected. Iron spots can sometimes be identified, after installation. This is due to oxidisation of iron materials within the matrix of the stone. This does not affect the structural integrity of the stone.

What sets Marshalls natural stone apart is our rigorous selection process, which ensures a subtle, consistent colour blend across your project while retaining the unique beauty of natural stone.

If you have any concerns or require clarification, please contact our Group Technical Services Team.

Staining

Some common garden chemicals can cause staining on paving surfaces. Always refer to the manufacturer’s instructions and warnings on the chemical container before use.

If a spill occurs, it is important to act quickly. Immediately rinse the affected area with clean water to reduce the risk of permanent staining.

For further advice on maintenance and stain prevention, please refer to the Marshalls Cleaning & Maintenance Guide, available on our website.

Marshalls Commitment to Quality & Innovation

At Marshalls, we are dedicated to continuous innovation, product development, and manufacturing excellence. Our goal is to ensure you receive products that offer long-lasting performance and genuine enjoyment in use.

Please note the following:

·        Product evolution is ongoing, and specifications may change without prior notice. We recommend checking with your local stockist to ensure you have the most up-to-date information before purchase or installation.

^·        Where applicable, all Marshalls products are manufactured to relevant European Standards. In cases where no British or European Standard exists for a product or its intended use, 

·        All products are supplied in accordance with Marshalls Standard Conditions of Sale. Copies of these terms are available on request. Any liability arising from statements, warranties, or representations is strictly limited as outlined in those Conditions.

For further information or guidance, please contact your Marshalls representative or our Group Technical Services Team.

Health and Safety

Care must be taken when handling and installing Marshalls products to ensure safe working practices are followed at all times.

COSHH (Control of Substances Hazardous to Health) guidelines are available for all Marshalls products and provide important information on safe usage and handling. These documents can be accessed via our website or by contacting our Group Technical Services Team.

We strongly recommend that all relevant safety information is reviewed before beginning any installation or maintenance work.