Question 1

How many tiles per m² for each type?

Accepted Answer

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.

Question 2

Which is cheaper for a complete roof?

Accepted Answer

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.

Question 3

What minimum roof pitch does each type need?

Accepted Answer

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.

Question 4

Which tile type is heavier?

Accepted Answer

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.

Question 5

Which looks better?

Accepted Answer

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.

Feature	Interlocking Tiles	Plain Tiles
Tiles per m²	10-15	~60
Material cost per m²	£25-40	£40-150
Weight per m²	43-55 kg	65-75 kg
Minimum pitch	17.5-22.5°	35° (30° enhanced)
Installation speed	Fast — large tiles	Slow — many small tiles
Wind resistance	Good — mechanical interlock	Good — double lap + nailing
Aesthetics	Modern, uniform	Traditional, fine texture
Battens required	Wider spacing (~340mm)	Close spacing (~100mm)

Interlocking vs Plain Roof Tiles — UK

Side-by-Side Comparison

When to Choose Interlocking Tiles

When to Choose Plain Tiles

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