​Choosing to invest in roof coating is a sensible decision for homeowners looking to protect their assets from the aggressive Scottish climate. However, the performance and benefits of coating differ significantly depending on your roof's material. Whether you have modern concrete tiles or traditional clay tiles, understanding the material science behind each will clarify which benefits most and why.
The key distinction between concrete and clay tiles lies in their water absorption rates. Concrete tiles absorb approximately 12-13% water by volume, whilst clay tiles absorb only around 6%. This difference fundamentally affects how each material responds to coating and which derives greater benefit from the treatment.
Concrete roof tiles are inherently porous. Whilst robust when new, their surface erodes slightly over time, increasing their absorption rate. This means they soak up water easily, which makes them heavy, encourages moss and lichen growth, and subjects them to the destructive freeze-thaw cycle in winter.
For concrete tiles, the benefits of coating are immediately transformative. The specialised coating penetrates the tile surface and dramatically reduces porosity, preventing water absorption and strengthening the tile against spalling and cracking. For concrete, the coating acts primarily as a protective seal and strength enhancer, effectively stopping biological growth and water ingress.
Concrete tiles receive the greatest benefit from coating because the treatment addresses their fundamental weakness: high water absorption. The coating can reduce absorption significantly, extending tile life and preventing the weight gain that occurs when uncoated concrete tiles become saturated.
Clay tiles are naturally less porous than concrete due to the vitrification process during firing, where minerals in the clay bond chemically to form a denser, more water-resistant material. Quality clay tiles are often manufactured to perform well without additional coating.
However, coating still provides valuable benefits, though the focus differs from concrete. Clay tiles benefit from coating primarily through surface protection and preservation rather than fundamental porosity reduction. The coating fills minor surface imperfections, provides an additional barrier against biological growth, and helps preserve the tile's appearance over time.
Even minor cracks allow water in, which can freeze and expand, leading to larger fractures. A quality roof tile coating fills these minute imperfections and provides a resilient surface that water runs off easily. This makes it difficult for moss to adhere and helps maintain the tile's structural integrity.
Concrete tiles derive significantly greater benefit from coating for several reasons:
Clay tiles certainly benefit from coating, particularly in terms of aesthetic preservation and filling surface imperfections, but their naturally lower porosity means they often perform adequately without additional treatment, especially if properly manufactured and maintained.
Regardless of whether your roof is covered in concrete or clay, the underlying principle remains the same: the substrate must be sound before coating. The best solution for a long-lasting finish is comprehensive preparation.
Whilst coating systems excel at sealing minor surface imperfections and reducing porosity, they cannot fix structural problems. Our process always includes replacing any individually cracked, broken or failing tiles. Only once the roof is structurally sound is the coating applied. This approach ensures the longevity of the entire roof system.
The difference in approach lies in the material's nature: concrete tile coating focuses on reversing high absorption and preventing degradation, whilst clay tile coating emphasises surface preservation and enhancement of already-good natural properties. Both materials benefit from the waterproofing and biocide properties found in modern coatings, but concrete tiles experience a more dramatic transformation.
Don't wait for the Scottish weather to cause irreversible damage to your property. Choose a professional partner who understands both concrete and clay tiles. Contact LTI Transformations today to schedule your free inspection and receive expert advice tailored to your roof's specific material.