Metal roof tiles or clay tiles for a reroof: comparing two estimates

Price stripping, waste removal, structural repairs and new layers separately. Removing the covering may reveal hidden damage. Agree how the contractor will document and price it. Base the contingency on the risks identified and define the contractual scope after inspection.

For phased work, include temporary weather protection. Agree how much roof can be opened at once and who protects the interior. Include the cost of these arrangements in both estimates.

Metal roof tiles generally weigh less than clay tiles, but compare the actual products. If one covering weighs 5 kg/m² and the other 45 kg/m², their weights on 106 m² are 530 kg and 4,770 kg respectively. This calculation covers only the roof covering and excludes battens and other components.

Have the structure and loads assessed before choosing the heavier system. The house’s age and the appearance of rafters viewed from below do not establish capacity. Damaged members may need repair even with a light covering. Snow, wind and the weight of the complete build-up still count. Multiplying the covering weight by area is only a materials calculation.

Define the same limits for both schedules. Include eaves, ridge, valleys, chimneys, service penetrations and roof access equipment. Add drainage, ventilation and any required snow retention. An omitted item can make one estimate appear cheaper.

Compare complete systems, including metal flashings. Check the pricing unit too. Steel sheets may be priced by overall or effective cover area. Clay tiles may be quoted per piece, then converted to a square-metre figure. Both systems need a layout or cutting plan for the actual slopes.

A simple gable roof differs from a slope interrupted by several valleys. Long sheets reduce laps but need suitable transport and careful handling. Small modules allow staged deliveries. A clay tile layout must also allow for edge units and cuts.

Ask for both the order quantity and the area derived from the measured roof. The difference should be explained. A universal waste percentage cannot suit every roof shape. Check which offcuts can be reused: their profile direction, joint and edge condition determine their suitability.

Rain noise depends on the complete roof. Insulation, airtightness, linings and connections to the structure all influence what occupants hear. Tapping two loose samples says little about the sound in a finished attic bedroom.

The same applies to temperature. Roof colour and surface finish are only part of the picture. Insulation, roof ventilation and window shading also affect comfort. Use the refurbishment to address weak spots throughout the assembly. A more expensive outer layer cannot correct air leaks along the slopes or missing insulation at the wall plate.

Ask about inspections, chimney access and replacing damaged units. With metal sheets, check the coating, edges and compatibility of repair materials. With clay tiles, consider whether a single tile can be replaced and the correct shape obtained. Flashings need checking on both systems.

Read the warranty coverage and the owner’s maintenance duties. A warranty period still requires the specified upkeep. Keep the specification, colour and installation records. Compare the cost of complete, correctly built assemblies when making the final decision.