What to do, and when

Twice a year, from the ground

You do not need to be on the roof to find most problems. A slow lap of the house at a low angle finds nearly all of them.

Deal with growth properly

Moss and algae hold water against the surface. Treat and brush gently, or fit zinc or copper strip near the ridge. Never pressure wash an asphalt roof — it strips the granules and takes years off it in an afternoon.

Look in the attic after heavy weather

Check after the first real weather of the season rather than at the end of it. A small stain found in autumn is a cheap repair; the same stain found in spring is not.

Clear the gutters before the wet season

Blocked gutters back water up under the bottom course of shingles and rot the fascia behind them. This is the highest-value hour of maintenance there is, and here it wants doing before November through March.

Cut back anything touching the roof

Branches abrade the surface in wind and drop debris that holds moisture. Keep growth well clear of the covering, and clear of the gutters while you are at it.

Keep the penetrations honest

Rubber pipe boots are the single most common source of leaks on an otherwise sound roof, and they are cheap to replace before they fail.

In short

Put two dates in the calendar, one either side of November through March. That is the whole programme.