Roof painting for metal roofs and cladding

What roof painting involves

A roof coating job starts with a survey. The type of sheet, its existing finish, the extent of corrosion and the condition of fixings, flashings and gutters all decide what preparation and which system are suitable. Plastisol-coated steel, bare galvanised steel and previously painted sheets each need a different approach, and a coating that bonds well to one can fail quickly on another.

The roof is then cleaned, usually by pressure washing, to remove dirt, chalking, moss and loose coating. Rust is treated and loose or flaking paint is taken back to a sound edge. Only then are the primer and finish coats applied, by spray, roller or brush depending on the profile and access. Cut edges, overlaps and fixings, where corrosion starts, get particular attention.

• Survey of sheet type, finish and condition
• Pressure washing and removal of loose coating
• Rust treatment and edge corrosion repairs
• Primers and finish coats matched to the substrate
• Gutters, flashings and fixings detailed

Metal roof painting and coating systems

Metal roof painting is not a single product. Systems range from direct-to-metal finishes for sound, previously coated sheets to high-build elastomeric coatings that bridge minor defects and resist standing water. Where cut-edge corrosion is present, a dedicated edge treatment is applied before the main coats. The manufacturer’s data sheet governs surface preparation, spreading rate and recoat times, and we follow it rather than improvising.

Colour choice matters more on a roof than on a wall. Dark colours absorb more heat, which increases thermal movement in the sheets, and some coating systems limit the colours that can be used over them. Light, reflective finishes can reduce heat gain in the building below, which is worth considering on large south-facing slopes.

Cladding painting at high level

Cladding painting on the upper elevations of a unit is often programmed with the roof, because the same access equipment serves both. Vertical cladding is cleaned and prepared in the same way as roof sheets, and coatings are chosen for the exposure the elevation faces: a sheltered north wall and a sea-facing gable age very differently.

Where cladding panels are badly corroded, delaminating or physically damaged, coating is not a repair. Panels in that condition need a cladding specialist, and painting over them only hides the problem until it worsens. The survey distinguishes surfaces that are genuinely repaintable from those that are not.

Access, weather and working around a live site

Roof work needs the right access: mobile towers, scissor lifts, booms or fixed scaffolding, chosen to suit the building and ground conditions. Fragile rooflights and sheets are identified before anyone goes up, and the work is planned so the building can usually stay operational below, with entrances and loading areas kept safe and clear.

Exterior coating is weather-dependent. Rain, dew, high wind and low temperatures all stop work, so programmes build in flexibility and coatings are only applied within the conditions the manufacturer allows. In practice that means most roof coating happens between late spring and early autumn, with settled weather windows chosen as the job approaches.

What affects the cost

The cost of roof and cladding coating depends on the area to be coated, the access required, the condition of the sheets and how much preparation they need, the coating system specified and the number of coats. A roof with widespread cut-edge corrosion is a very different job from a sound roof that simply needs a colour change.

A site survey lets us measure, check the sheet type and condition, and give you a written quote that sets out the preparation, the system and the coats included, so you can compare it fairly with any other quotation.