Even the toughest roof tile can fail if the system around them breaks down. Here is how leaks typically develop:

• Cracked or Smashed Tiles: Impact from heavy branches, owners or tradies walking incorrectly can cause cracks that can allow water to track down into the roof cavity.

• Displaced Tiles: Strong winds can cause tiles to slip out of alignment. Since tile roofs rely on a precise "lap" to shed water, even a small gap creates an entry point for driving rain.

• Worn Mortar Pointing: Traditionally, the ridge and hip caps are held in place by mortar. Over time, this mortar becomes brittle, cracks and falls out. This not only loosens the tiles but creates large gaps where water can easily penetrate the roof peak.

• Degraded Underlayment: Concrete tiles act as a primary rain screen, but the sarking (underlayment) is the secondary waterproof barrier. In older homes, this material can become brittle and tear; once it fails, any water that gets past a tile becomes an internal leak.

In New Zealand, long-run steel (particularly Colorsteel) is the gold standard for modern homes. Some common problems we see:

• Fastener Failure: This is the #1 culprit. Each sheet is held down by dozens of screws. Each screw has a rubber washer. The harsh NZ sun can cause these washers perish, crack, or lose their "spring," allowing water to track down the screw thread directly into your timber framing.

• Flashings and Valleys: The "apron" flashings (where the roof meets a wall) and valleys (where two roof planes meet) are high-volume water paths. If these are blocked by pine needles or pohutukawa debris, water can back up and overflow the internal upstand.

• Skylights: These are notorious. Over time, the seals between the glass and the frame can fail, or the custom flashings around them can become blocked with debris, causing water to back up and overflow into the house

• Internal Gutters (The Silent Killer): Popular in many 1990s and early 2000s Kiwi designs, internal gutters are hidden behind the roofline for a "seamless" look.

  If these gutters get blocked by leaves or debris, the water has nowhere to go but into the wall cavity or over the top of the internal fascia. Unlike external gutters, you won't see them overflowing on the outside; you'll just see a wet patch on your internal ceiling.

Decramastic tiles, with their classic metal-panel-and-stone-chip look can be prone to:

• Lichen and Moss - These harmless looking growths hold onto moisture and eat away at your roof’s protective layer and allow water in.

• Corrosion - Water isn't their only enemy. The galvanized steel panels are subject to corrosion, especially in coastal areas or if the protective coating is damaged. This leads to rust, weakening the structure and inviting leaks.

• Panel Damage: The primary driver. Dents, cracks, or punctures in the thin metal panels create direct pathways for water to seep through, bypassing any underlay.

• Flashing Failures: Like any roof, flashing around chimneys, vents, skylights, and valley sections is a critical weak point. If flashing is improperly installed, damaged, or corroded, water will find its way in.

Despite their reputation for being incredibly wind-resistant, asphalt shingle roofs have specific vulnerabilities:

• Wind Uplift" and Tab Failure: Asphalt shingles rely on a strip of thermal sealant (a line of glue) that activates in the sun to bond the shingles together.

• Nail ‘Back outs’: Due to the natural expansion and contraction of the wooden roof deck (sarking) beneath the shingles, nails can slowly "pop" or back out over time. This creates a tiny hump in the shingle above it, which eventually wears a hole through the material or allows water to track down the shank of the nail into the wood.

• Granule Loss and UV Degradation: As shingles age, they lose these granules (you’ll often see them piling up in your gutters). Once the granules are gone, the sun "bakes" the bitumen, causing it to crack and curl. These cracks allow water to seep through the body of the shingle.