Managing Ground Levels in Historic Buildings to Prevent Damp

Damp issues in historic buildings are often caused by raised ground levels, which trap moisture against walls and prevent the building from breathing as it was originally designed to. Over time, paving, landscaping, and other alterations can lead to moisture bridging, where water becomes trapped against masonry, causing rising damp, timber decay, and structural deterioration.

Why Ground Levels Matter

Many period buildings were constructed with exposed brick plinths, lime mortars, and natural drainage routes to regulate moisture. When these features are buried or obstructed by raised external ground levels, it can result in:

• Water pooling against walls, accelerating brick and stone decay.
• Blocked ventilation gaps, reducing airflow and increasing internal damp.
• Moisture bypassing breathable materials, leading to rising damp inside the building.

Lowering Ground Levels and Managing Drainage

One of the most effective ways to reduce damp in historic buildings is to carefully lower external ground levels while ensuring proper drainage. In many cases, installing a French drain alongside the base of the wall can help redirect excess water away from the building, preventing moisture buildup.

A well-designed French drain typically includes:

• A gravel-filled trench to absorb and disperse water.
• A perforated drainpipe to carry excess moisture away.
• A breathable finish to prevent water from becoming trapped against walls.

Simply lowering ground levels without addressing drainage can still leave moisture issues unresolved, making French drains an important consideration in many cases.

A Conservation-Led Approach to Damp Prevention

At Craft Build, we take a careful, conservation-led approach to damp management in historic buildings. Lowering ground levels, combined with appropriate drainage solutions such as French drains, helps maintain breathability and protect historic masonry from long-term damage.

If your building is experiencing damp problems, assessing external ground levels and drainage could be key to finding the right solution.