Interlocking vs Plain Roof Tiles — UK

Interlocking tiles require approximately 10-15 tiles per m² depending on the profile (e.g. Marley Modern 10/m², Redland Grovebury 10/m²). Plain tiles require approximately 60 tiles per m² at standard gauge (65mm headlap, 100mm gauge). This massive difference in quantity affects installation speed, labour cost, batten requirements and structural load.

Interlocking tiles are significantly cheaper overall. Material cost is roughly £25-40/m² for interlocking vs £40-70/m² for machine-made plain tiles (or £80-150/m² for handmade clay plains). Labour is also much less — interlocking tiles cover the roof 4-5 times faster. A typical 100 m² roof costs £4,000-6,000 with interlocking tiles vs £7,000-12,000 with plain tiles.

Interlocking concrete tiles typically require a minimum pitch of 17.5-22.5° depending on the profile and exposure. Plain tiles require a minimum pitch of 35° (or 30° with enhanced headlap). This means plain tiles cannot be used on lower-pitched roofs. Interlocking tiles are the only option for many modern roof designs with shallow pitches.

Plain tiles create a heavier roof covering. Despite each individual tile being lighter, the sheer quantity means a plain tile roof weighs approximately 65-75 kg/m², compared to 43-55 kg/m² for interlocking concrete tiles. This affects rafter and truss sizing — always check that the roof structure is designed for the tile weight you choose.

This is subjective, but plain tiles are widely considered more attractive, especially on traditional and period properties. Their smaller size creates a finer texture with attractive coursing lines. Handmade clay plain tiles with their slight colour and shape variation are the premium aesthetic choice. Interlocking tiles look more uniform and modern — some profiles like Redland Rosemary or Marley Edgemere attempt to bridge the aesthetic gap.