Waterproofing Exterior Stone Walls

Waterproofing Exterior Stone Walls

Providing a permanent solution to damp is a real headache for any homeowner, but is especially the case when it comes to older properties. Why is this? Well, to put simply, modern buildings are constructed with damp in mind, often using cavity walls to create a barrier between the exterior wall and interior wall.

However, many older properties and some newer properties are built using a solid wall construction, which can create problems.

In this guide we cover:

• Breathability
• Nano-technology
• 25+year performance
• Heat retaining

Breathability

Why Can Solid Wall Construction Lead to Damp Problems?

Cavity walls were introduced in the 19th century to help buildings breathe. They work by creating a small gap between two layers of brick, tied together with metal, allowing moisture to escape rather than travel indoors.

Solid wall buildings, however:

• Have no cavity gap
• Are made from a single layer of brick or stone
• Can absorb rainwater directly into the structure

When rain drives into the wall, it moves through tiny capillaries in the material and can eventually appear on internal surfaces. This is known as penetrating damp.

Why Standard Waterproofing Sealers Cause Problems

Many people assume that waterproofing a stone or brick wall with a sealer will solve damp issues, but for older properties, this often makes things worse.

Typical stone and brick sealers:

• Create a surface film that blocks moisture from entering the wall
• But also trap internal moisture inside the building
• This trapped moisture appears naturally from everyday life (cooking, showers, breathing)

When moisture can’t escape:

• Walls start to break down
• Large damp patches form internally
• Structural deterioration can occur, sometimes causing irreversible damage

The Correct Solution: Use a Breathable Waterproofing Product

To protect stone or solid walls without trapping moisture, you need a product that is highly breathable.

Look for a stone waterproofing treatment that has:

• SD value below 1 (indicating high breathability)
• Ability to repel rainwater while still allowing vapour to escape
• Protection against penetrating damp without sealing moisture inside

Learn more: Breathability 

Nano-Technology

The ideal technology for waterproofing stone walls is a highly breathable masonry protection cream. They create an invisible barrier on exterior walls that repels water, while remaining highly breathable. It is crucial to avoid any product that refers to itself as a sealer, as these products are often the less advanced film building waterproofers.

In the case of an advanced masonry protection cream, these products chemically bond to the stone wall, giving the stone itself waterproofing properties rather than simply creating a waterproof layer on the surface.

By forming a part of the material, it does not negatively affect the breathability. It lines the pours of the material without sealing them completely, meaning it repels water from outside while still allowing moisture from inside to escape.

In an independent test, conducted by UKAS accredited laboratory Lucideon, Emperor Masonry Creme was tested in an accelerated 25-year weathering test.

The results of the tests demonstrated that Emperor Masonry Creme:

• Reduced water absorption by 96.3%
• On average to keep houses 6°C warmer compared to not treated properties
• Maintained excellent breathability with SD values of 0.56, while a non-treated wall had an SD value 0.57

Learn more: Nano-technology 

25+ Year Performance

The 25-year accelerated weathering test also demonstrated that the waterproofing treatment showed no signs of deterioration in performance or change in aesthetic after the test was completed.

This meant the treatment remained just as effective at regulating moisture even after 25 years, while the exterior walls looked exactly the same as before the test. This is a major benefit of Emperor Masonry Creme, especially for older properties.

The treatment dries clear with no film or shine. As it repels water, it also repels dirt, which washes away with rain and keeps the stone looking clean. It also reduces moss and green growth, as these rely on moisture.

Acting as an exterior wall preserver, Emperor Masonry Creme helps maintain the beauty of aging buildings, allowing them to withstand harsh weather for many years.

Heat Retaining

Moisture is one of the biggest causes of heat loss in properties. Wet walls act as a thermal bridge, helping heat to transfer out of a much quicker than a dry wall.

The masonry cream by limiting the moisture in buildings is heat retaining. The Lucideon tests showed that the wall treated with Emperor Masonry Creme stayed 6°C warmer on average than a non-treated wall.

Learn more: Heat retaining

If you have more questions, we are here to help with our in-house team of experts. You can chat to them by emailing [email protected] or give them a ring them on 01254 936121.

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