Estimate your new roof cost in three steps: measure your roof area, multiply by the per-m² rate for your material, then add scaffolding and a 15% contingency. That gives you a solid budget figure before you speak to a single contractor.

Step 1 — Measure your roof area

You do not need to go up on the roof. Measure your ground-floor footprint (length × width in metres) and multiply by 1.4 for a standard sloped roof.

Example: A semi-D measuring 7m × 9m = 63 m² footprint × 1.4 = 88 m² of actual roof surface.

Step 2 — Apply the per-m² rate

MaterialCost per m² (2026)
Concrete tile€60–€90
Synthetic slate€70–€100
Natural slate€110–€160
Fibreglass flat roof€80–€110
EPDM flat roof€90–€120

Example continued: 88 m² × €75 (mid-range concrete tile) = €6,600 for materials and labour.

Step 3 — Add scaffolding and contingency

For a standard two-storey semi-D, scaffolding runs €1,200–€2,000. On a house over 25 years old, add 15% extra for potential hidden structural damage underneath the old tiles.

Full worked example:

ItemCost
Materials and labour (88 m² × €75)€6,600
Scaffolding€1,600
Contingency 15%€1,230
**Total budget****€9,430**

How to use this against real quotes

When written quotes arrive, apply this formula to each one. If a quote is more than 25% above your calculation, ask the contractor what is driving it. If it is more than 25% below, ask what has been left out — usually scaffolding, skip hire or the structural contingency.

This method is accurate enough to avoid nasty surprises. It is not a substitute for three written, itemised quotes from CIF-registered contractors.

Try our free roof cost calculator — get your estimate in under a minute.

More resources: Roof cost per m² Ireland · Roof replacement cost by house type · Hidden costs of roof replacement