How Much Fascia and Soffit Do I Need?

How We Calculated This

Fascia and soffit run along the eaves (where the roof overhangs the walls):

• Front eaves: ~7m
• Rear eaves: ~7m
• Side verges / gable ends: ~5m each side
• Total: ~24m
• Sold in 5m lengths: 24 ÷ 5 = 5 lengths of each

Typical House Measurements

• Mid-terrace: 12–16m (front and back eaves only)
• End-terrace: 16–20m (front, back, plus one side)
• Semi-detached: 20–25m (front, back, plus exposed side)
• Detached: 25–35m (all four sides)
• Bungalow: 30–40m (larger perimeter at eaves level)

Board Sizes

• Fascia board: 150mm, 175mm, 200mm, or 225mm wide × 5m long
• Soffit board: 100mm, 150mm, 200mm, 250mm, or 300mm wide × 5m long
• Material: uPVC (most common), timber, or composite

Additional Components

• Ventilated soffit: Required for loft ventilation (typically every other board or continuous vent strip)
• Corner joints: One per external/internal corner
• Inline joints: One per board joint (where 5m lengths meet)
• Starter trim / J-trim: Runs along the wall to hold the soffit edge

Tips

When replacing fascia and soffit, it’s most cost-effective to do it at the same time as replacing guttering. Check the rafter feet for rot before installing new boards. Use stainless steel or A4-grade screws for fixing. Ensure adequate ventilation — Building Regulations require continuous 10mm ventilation at eaves level (equivalent to 25mm at the soffit for a pitched roof).