Sometimes another patch repair is genuinely the right call. Other times, you are throwing good money after bad and it is time to bite the bullet on a full re-roof. Here are seven honest signs it is the latter.

1. It is over 60 years old

Concrete tile roofs from the 1960s and 70s are at end-of-life. Individual repairs will keep patching, but the underlying felt is disintegrating and the batten timber is often perished. Full re-roof is more cost-effective than three more years of £600 repairs.

2. Multiple tiles slipping in the same rain event

One tile in a storm is bad luck. Six tiles is a warning that the nail plates or battens are failing across the roof. Individual re-fixing is a temporary measure.

3. The ridge line has visibly sagged

Look at your roof from across the street. The ridge line should be dead straight. A dip in the middle means the roof timbers are moving. This is structural. Full re-roof plus timber remedial required.

4. Extensive moss and lichen growth

Moss holds moisture against the tiles. Over years, freeze-thaw cycles crack the tiles. If more than 40 percent of your roof is green, tile replacement across the whole slope is due.

5. Interior damp stains in multiple locations

Single leak: repair. Damp on ceilings in three different rooms: the underfelt has failed across the roof. No amount of patching from outside will fix an underlay problem. Strip and re-felt.

6. Energy bills climbing

If your heating bills have crept up 20 percent over 5 years with no other changes, poor insulation and draughts through failing roof underfelt are a real culprit. A modern re-roof with breathable membrane and PIR insulation to current U-values will pay back in 8 to 12 years on the fuel savings alone.

7. You are selling and the survey has flagged the roof

Homebuyer surveys grade the roof. Anything worse than "average" holds down the sale price by more than the cost of a re-roof. Get it done before you list.

Costs to expect

  • 3-bed semi, concrete tile re-roof: £5,500 to £7,500
  • 3-bed semi, slate re-roof: £9,000 to £13,000
  • 4-bed detached, tile: £8,500 to £12,000
  • 4-bed detached, slate: £14,000 to £20,000

Includes strip, disposal, new breathable membrane, new treated battens, new tiles or slates, ridge, all lead work, 10-year workmanship guarantee.