Choosing a roof covering for your home: how to compare the options

Start with the drawings. They show the roof geometry, design loads and build-up. If you change the covering, check that the structure and its details are still suitable. This also applies when replacing a heavy covering with a light one. Lower weight does not address wind uplift or compensate for incorrect fixings.

The pitch must be within the range permitted for the specific product. There is no single minimum that applies to all tile-profile sheets or all T18 sheets. Slope length, sheet laps and sealing requirements also matter. A product suitable for one roof may be unsuitable for another.

Check the planning requirements for the plot. They may specify the shape, pitch or colour of the roof, narrowing your options before you open a catalogue. If the house is protected as a historic building, further restrictions may apply. Establish what alterations are permitted when assessing materials.

Sheets cut to length suit simple roof slopes. A laying plan can minimise the number of end laps. Accurate measurements help the roofer achieve an even pattern and lay the sheets efficiently. An incorrect measurement on a long sheet can be costly.

Plan transport, unloading and lifting onto the roof in advance. A large sheet is light for its area but can bend if lifted incorrectly. Numerous valleys and short slopes require a careful cutting plan. Long sheets can produce considerable waste on such roofs.

Short sheets are easier to transport and handle. They also make it easier to plan the sequence of work on a complex roof. For a later repair, replacing a single module may be easier than removing a very long sheet. The replacement must match the model, coating and fixing system.

Modular sheets still have a defined position and orientation. Laying direction, side laps and the shape of the pressed profile determine how the sheets fit together. Do not mix sheets from different systems. Convert the price per module to a cost per square metre of roof covered, using the actual cutting plan.

Trapezoidal steel sheet has a distinct, regular rib pattern that can suit a contemporary home, outbuilding or garage. T18 has a shallower profile, while T35 produces a more pronounced pattern. Appearance alone is insufficient: check sheet thickness, load capacity, supports and connections.

With other properties comparable, a deeper profile can be stiffer. Support spacing must still be checked separately. For a prominent façade or low roof, look at a full sheet. A small colour sample does not show how light falls across deep ribs.

Clay and concrete roof tiles differ from thin steel sheets in both weight and fixing method. The structure must be designed for them. Bituminous shingles need a suitable deck and ventilation arrangement. Standing seam panels have their own requirements for support, fixing and thermal movement. Follow the instructions for the material you choose.

Compare the acoustic performance of complete roof assemblies. The outer covering alone does not determine how much noise reaches a bedroom below. Insulation, airtightness, underlay and internal lining all contribute. Likewise, choosing steel instead of tiles does not in itself provide thermal insulation.

List the required pitch range, exposure to corrosion, appearance, budget and maintenance needs. Add the insulation arrangement and any planned rooftop equipment. Photovoltaic panels and roof access systems need suitable fixings regardless of the colour of the covering.

Then compare complete material packages for the same design. Include underlay, flashings, ventilation, gutters, transport and labour. Ask for warranty terms and storage instructions. Even a material that works on the drawings can be difficult to use if there is no room to store it safely on site.

Before ordering, hold a sample beside the façade finish and window frames. Look at it in sunlight and shade. The same graphite finish can look noticeably different in colour and gloss as the light changes.

Choose a covering that fits the design, site conditions and the contractor’s capabilities. Price sheets cut to length for a simple slope and compare modules for a more intricate roof. Assess T18 and T35 against the documentation for the exact profile.