Importance of Guttering: Leaky Gutters and How to Identify Them

Why are gutters so important for old buildings? Gutters play a vital role in protecting old buildings from the damaging effects of damp. Their significance is often underestimated by both homeowners and tradespeople. Over time, faulty gutters can cause substantial damage, including:

• Render damage: Water ingress can degrade render and plaster.
• Mortar erosion: In stone buildings, water can wash away crucial mortar joints.
• Damp conditions: Leaky gutters contribute to rising damp and mould growth within the property.

Proper gutter installation on an old building requires specialised knowledge and careful consideration. Faulty gutters can be challenging to detect, as leaks often only become apparent during specific weather conditions. In my experience as a building surveyor, a significant number of older properties I inspect exhibit guttering issues. Moreover, a considerable portion of the remedial work I have undertaken as a lime mason stems from the detrimental effects of leaky gutters.

Addressing guttering problems is one of the most cost-effective measures to protect an old or listed property from damp and maintain its structural integrity. Investing in a professional gutter assessment can save homeowners significant costs in the long run by preventing costly repairs and preserving the building's value.

Why are gutters necessary to keep my old building dry?

The UK experiences substantial rainfall annually. For a typical small house, this translates to a considerable volume of water that must be effectively managed. If this water is not intercepted by a properly functioning gutter system, it cascades down the walls, saturating the ground around the building's base. Even a small leak can concentrate water flow, leading to severe localised damage.

The walls of most buildings, particularly older ones, are water-resistant rather than waterproof. This means that prolonged exposure to moisture can lead to:

• Penetration: Water can seep into the walls, increasing internal humidity and encouraging the growth of mould and fungi.
• Reduced thermal efficiency: Damp walls are poor insulators. This can lead to condensation and further damp issues.
• Damage to render and plaster: As moisture evaporates, it can exert pressure on render and plaster, causing cracks and deterioration, as well as widespread failure of the material.
• Structural damage: Timber components embedded in the wall such as floor joists and lintels will begin to rot. Cob buildings are particularly vulnerable to leaks from gutters, and may eventually suffer structural failure.

How should I go about surveying and assessing my gutters?

Identifying faulty gutters often involves recognising the symptoms of water damage:

• Wall discoloration: Dark stains or patches of algal growth on walls.
• Vegetation growth: Plants sprouting from mortar joints.
• Fascia board damage: Peeling paint, rot, or signs of water ingress.
• Mortar discoloration: Darker mortar joints below faulty outlets often indicate water leakage.

A more thorough inspection requires a closer look at the gutter system itself:

• Water flow: Observe how water flows through the gutters, checking for blockages, leaks at joints, and proper discharge from downpipes.
• Alignment: Ensure the gutter is correctly aligned with the roof to prevent water from being blown back behind it.
• Fascia board alignment: The fascia board should be vertical to ensure proper gutter alignment.

What shape gutter should I use to prevent damp?

The profile of a gutter is more than just an aesthetic choice. Higher-capacity gutters, such as ogee or square profiles, are less prone to blockages and better equipped to handle heavy rainfall. While half-round gutters are suitable for smaller roofs, they are more susceptible to spillage, especially if not installed perfectly.