A very prevalent issue found in home inspections is leaking roofs. Home inspections indicate that when diagnosing and repairing leaking roofs, there are three key issues to consider:
The state of the covering of the roof. This includes scratched, broken or dislodged tiles or slates, weathered thatch, bent or corroded roof sheeting. Incorrect installation can make it ineffective for any form of roof coverings -Can A Damaged Gutter Cause Roof Leaking.
The roof’s pitch. In general, only “flat roofs are water-proofed; most “weather-proofed” pitched roofs are. This implies that to prevent rain water from entering the roof covering, the roof is built to shed water rapidly. The steeper the pitch of the roof, generally speaking, the less likely it is that the roof will leak.
The places where roof surfaces intersect with walls, chimneys or other roofs are vulnerable points in relation to possible leaks. These intersections are normally weather-proofed with one form or another of “flashing”.
Tiles The home inspector will search for tiles or slates which are cracked, damaged or dislodged. Weak construction techniques that can result in leaks include: broken mortar on ridge or barge capping tiles; lack of mechanical tile fixation along eaves and ridges in vulnerable areas; and too low a roof pitch.
Slates Slates are commonly built – often bituminous felt (malthoid) – over a water-resistant underlay. Leaks come from fractured or dislodged slates and from a base that has died. If mild steel was used instead of copper or aluminium repairing nails, then corroded nails could also lead to slipping slates. Ridges on slate roofs are usually finished over a double soaker” with facing ridge slates – this is an alternating layer of underlay running over the ridge. If this double soaker is broken or lost, leaks can occur along the ridges.
Roof sheeting The roof sheeting of metal also corrodes around the overlaps and around the screws of the fixing. Popular installation errors are too short end-laps and insufficient side-laps that face the prevailing weather. There may also be an issue with broken and weathered fibre-cement or plastic roof sheeting.
Thatch In a thatched roof, which is exposed to the elements, the top layer of grass eventually rots and must be regularly combed out and replaced to retain the weatherproof characteristics of a thatched roof.
This can be either concrete slabs or boards – often surrounded by parapet walls. Semi-flat roofs Such roofs must have proper drainage. It is necessary to effectively waterproof the top surface of the semi-flat roof – typically with heat-applied torch-on bituminous felt topped with UV-ray resistant silver aluminium paint. Leaks can occur if the waterproofing is old or has been poorly installed with insufficient overlaps or poor bonding to the substrate. The remedy is to either repair or uninstall the torched-on waterproofing and re-install it.