The most expensive part of painting the top of a house is not the paint, it is getting safely to it. When scaffold or access equipment is already up for roof, chimney or roofline works, the marginal cost of preparing and painting the high elevations, bargeboards, render, soffits and rainwater goods drops sharply. Doing it later means paying for access twice.
We treat painting as protection rather than decoration. Exposed timber that is left unpainted absorbs water, swells, splits and eventually rots, and the timber at the top of a house is exactly the material most exposed to driving rain from the south-west. Sound paint is the barrier that keeps that from starting.
The work includes making good: filling, sanding, treating and repairing the surfaces before anything is applied. Paint over a poorly prepared or already-damp surface fails within a season or two, and painting over rot hides a problem that will be more expensive when it finally surfaces.