A Guide to Cleaning and Maintaining Portland Stone

Portland Stone is renowned for its durability, elegance, and ease of maintenance, making it a popular choice for facades, internal flooring, and external paving. This natural stone requires minimal upkeep, and with the right care, it can maintain its pristine appearance for many years. Here’s a comprehensive guide to cleaning and maintaining Portland Stone across various applications.

Cleaning Portland Stone Facades

After the initial installation of Portland Stone facades, you might notice that the stone dries unevenly depending on the stone's texture, resulting in temporary variance in colour. This is a normal process, and the colour will settle evenly without the need for additional cleaning. Importantly, sealing the stone is not recommended, as it can interfere with the stone's natural breathability.

Maintenance of Portland Stone facades to safeguard the stone performance is generally unnecessary, except in exceptional circumstances such as defective water management. Given the low pollution levels in most UK cities, Portland Stone can outlast many other materials used in facade construction. However, when cleaning and surface repairs are required, they should adhere to the guidelines outlined in BS 8221-1 and BS 8221-2, as well as the Stone Federation’s guide on the cleaning of masonry surfaces. The cleaning cycle will depend on factors like the building’s design, local climate, facade orientation, and acceptable levels of atmospheric deposits as determined by the client.

Special care should be taken when cleaning nameplates or other fitments attached to Portland Stone cladding. To prevent staining the surrounding stone, use a tightly fitting masking plate during the cleaning process.

Cleaning Portland Stone Internal Flooring

For internal Portland Stone flooring, routine cleaning is simple. Sweep frequently with a soft brush or vacuum with the brushes down to remove dust and loose dirt. In high-traffic areas, occasional use of a rotary cleaning machine with pads or brushes can help maintain the stone’s appearance. For lower traffic areas, a weekly mop with clean water and a product like Lithofin Wash and Clean is sufficient.

It’s crucial to address spills promptly with a damp cloth and clean water to prevent stains from setting in. Portland Stone is susceptible to acidic contamination, so it’s best to avoid household soaps, detergents, and bleach, which can damage the surface. For more stubborn stains, Lithofin products are recommended, but always follow the manufacturer’s instructions carefully.

In some cases, old or dried-in stains, particularly from acidic substances, may be difficult or impossible to remove. These areas may require the expertise of a specialist stone restoration company.

Cleaning Portland Stone External Paving

Like facades, Portland Stone paving may dry unevenly after installation depending on the stone's texture. This discoloration usually resolves on its own, so additional cleaning is not necessary, and sealing is not advised.

In sheltered areas, occasional light brushing with water and a mild detergent such as Lithofin Power Clean followed by a water rinse may be needed to remove airborne dirt. In persistently damp or shaded areas, algae growth can occur, especially within the first two years. This can be controlled with a stiff broom, gentle jet washing (careful not to dislodge the grout), or the application of a stone-algae remover like Lithofin Outdoor Cleaner. After deep cleaning, Lithofin Algex can help inhibit future spore growth. Always manage the runoff from cleaning products to protect the surrounding environment.

If defective or leaking rainwater pipes cause water to spill onto the paving, it could deteriorate the stone over time. It’s important to rectify such issues promptly. For more challenging contamination issues, like rust staining, the Lithofin Technical Line can provide further guidance.

By following these straightforward cleaning and maintenance practices, Portland Stone can remain a beautiful and enduring feature of any building or landscape.

Tags: Cleaning Maintenance