Roof Replacement in Porto — Real Case 100 m²
Project type: full replacement of a traditional tiled roof
Location: Northern Portugal
BEFORE:
Leaking roof, musty smell inside, damp walls, mold inside and outside, bubbling plaster and paint, lack of ventilation and waterproofing.
Scope of works
1. Demolition Removal of old ceramic tiles Cleaning and preparation Waste transport and disposal
Important: Old roofs often hide: broken battens moisture damage previous “quick fixes”
2. Structure inspection Full check of timber structure Replacement of damaged elements (only where required)
Typical in Porto: partial rot due to humidity insect damage deformation over timeIgnoring this = short lifespan of new roof
3. Base layer - Installation of breathable waterproof membrane and Protection against wind-driven rain
4. Ventilation system Installation of battens + counter-battens Creation of airflow gap (critical in North Portugal)
Without ventilation: condensation forms under tiles mold develops inside insulation (if any) stops working
5. Tile installation New ceramic tiles, Fixing system, Alignment and finishing
Labour: from €25/m²
Tiles: from €10/m²
6. Drainage system Cleaning gutters Adjusting slopes for proper water flowWater management is part of the roof system — not a separate issue.
7. Logistics (included) Material transport Delivery to site Handling Often excluded in “cheap” offers.
Total: €11,030 + VAT Includes: materials labour transportFor reference: ~€110/m² (complete system)
Timeline 3–5 working days (after delivery of materials), depends on weather and structural condition discovered during demolition
AFTER:
new tiled roof, controlled airflow, waterproof base layer, predictable performance
Typical quote:
Tile replacement — from €25/m² but usually means: placing tiles only
Missing: membrane, ventilation, structure corrections, drainage adjustments, logistics.
10 questions every homeowner should ask before replacing a roof in Portugal:
1. Are you replacing just tiles or the full system?
2. Is membrane included? Which waterproof membrane are you using?
3. Is ventilation included in the roof system?
4. What tile loss percentage do you calculate?
Professional answer: usually 5–10%
If contractor says: “Almost zero” They probably underestimated the project.
5. Are gutters checked and adjusted? Is transport included?
6. Is waste removal included?
7. Which tile brand are you installing?
8. What warranty do you provide?
9. Can you show previous similar projects?
10. Do you provide written scope of works? If not: expect disputes hidden extras “this was not included”
Be careful if contractor:
- avoids written details
- gives only price per m²
- cannot explain ventilation
- refuses material specification
- promises “very fast and very cheap”
- says membrane or ventilation are “not necessary”
If you want a proper roof replacement — not just tiles on top of old problems — request a detailed quote with full scope, materials, and warranty.
- No hidden costs
- Full system (structure + membrane + ventilation + tiles)
- Clear timeline
- Written warranty