What roofing problems do we fix in Wellington?
These are the faults we see most across the region's villas, bungalows, state houses and coastal homes.
Leaks at flashings, penetrations and valleys
Most roof leaks start where the sheet stops: around chimneys, skylights, vents, valleys and the ridge. Water tracks along purlins and shows up metres away, which is why patching the stain on the ceiling rarely works. We trace the path, replace or re-seal the flashing, and check the timber it has been soaking.
Building Code clause E2 requires roofs to stop water getting in and causing damage. (MBIE, Building Code clause E2 External moisture)
Wind-lifted iron and loose fixings
Wellington's northerly and southerly gales work fixings loose over time, starting at the edges and ridges where uplift is highest. Once a sheet lifts, rain is driven straight under it. We refix with the correct screws and washers and replace sheets that have been bent or torn.
NIWA describes Wellington as windy, with the strongest gusts around the south coast and Cook Strait. (NIWA, Wellington regional climatology)
Rust and corrosion on coastal roofs
Salt settles on the sheltered parts of a roof that rain never washes, under eaves, laps and overhangs, and that is where rust starts. Caught early it can be treated and recoated. Left alone it eats through the steel and the sheet has to be replaced.
BRANZ recommends washing painted metal roofs every year, or every 6 months in severe marine areas. (BRANZ, Replacing a profiled metal roof)
Cracked, slipped and broken tiles
Concrete and clay tiles crack under foot traffic, falling branches and age, and the mortar on ridges breaks down. We replace damaged tiles, rebed and repoint ridges, and tell you honestly when the roof is past patching and a change to metal makes more sense.
BRANZ notes that a tile-to-metal change needs the wind uplift on the new roof assessed. (BRANZ, Replacing a concrete or masonry tile roof)
Overflowing spouting and blocked downpipes
When spouting overflows, water runs down the cladding and into the wall framing instead of away from the house. Leaves, moss, sagging brackets and undersized downpipes are the usual causes. We clear, rehang, rejoin or replace runs so water leaves the roof where it should.
Spouting forms part of the roof's E2 job of keeping water out of the building. (MBIE, Building Code clause E2 External moisture)
Moss, lichen and organic growth
Moss and lichen hold moisture against the coating and the timber under it, and on tiles they lift the edges. Shaded roofs in Upper Hutt valleys and bush-backed sections are the worst. We treat the growth, wash the roof, and look for the damage it has hidden.
BRANZ says regular washing is part of keeping a painted metal roof's durability. (BRANZ, Replacing a profiled metal roof)
Asbestos-cement roofing on older homes
Some homes built before 1960 still have corrugated asbestos-cement roofing, sometimes hidden under a newer roof. It is stable while left alone but must not be cut, drilled or water-blasted. We arrange testing first and plan removal under the right controls.
BRANZ flags asbestos-cement roofing as a risk on pre-1960 houses. (BRANZ, Replacing a profiled metal roof)