Breaking down each key area... Discover what must be monitored to ensure a well maintained roof.
Ridges - The peak of the roof where two roof planes meet. A common problems is missing ridge tiles or loose / lost mortar. With the modern dry ridge system regular checks are needed for missing / damaged clips, clamps and screw fixings. Checking for a straight ridge is also of high importance, a sagging ridge could indicate internal rot, causing structural weaknesses.
Valleys - The valley plays a similar role to the guttering system, however the difference is that it runs between the two sections of the roof plane. It is constructed with various materials, the most popular are lead and fiberglass. Its job is to efficiently run water into the guttering system. A well-know problem here is mortar used to secure and seal the end tiles can overtime work loose and detach away. This leads to a blocked valley and/or gutter hopper, forcing water to penetrate into the roof.
Tiles - Tiles play a simple role and normally don't require any maintenance. Most tiles can be seen from ground point too. However there can be some complications. On older properties weather can eventually break down the structural integrity of a tile, causing them to perish, break apart and slide down. This can be hard to see from ground point. With missing tiles, water will easily enter the internal structures of the roof, causing major complications.
Flat Roofs - A flat roof normally consists of felt or PVC. A well constructed flat roof design will last approximately 20-25 years with good maintenance. A common issue to look out for is cracking, caused by UV light and timber movement, this allows water to penetrate into the underside causing significant damage over time. Rusty or missing nails on old style felted roofs results in a similar scenario. On a roof constructed with little fall a build up of debris is common. When left, water will sit on the surface and pass through nails and joints.
Dormer and/or Skylights - Dormer: A roofed structure normally containing a window. Areas to check include, both valleys, the ridge, facia and its cladding. Skylights or Roof-lights are an efficient, low cost option for loft conversions or to simply provide more interior light. Regular checks on flashing, rubber seals and surrounding plastic trim is a must, over time cracks and pitting are common.
Chimney and Caps - The chimney is a ventilation structure made from masonry or metal, its job is to safely isolate and remove gases from a fire, stove or boiler. Regular inspections are vital when the risk is potential fire outbreak. When inspecting externally checks include brick and mortar condition, obstructions and the overall condition of the chimney cap.
Ventilation - Vents are installed into most roofing structures to keep internal condensation at bay. As warm air rises this ventilation offers an escape route. Many vents are now constructed into the ridge tiles so it's impossible to see when they become blocked by moss or similar vegetation. A blocked vent equals internal damp and condensation, regular checks are vital.
Guttering Systems - The purpose of any gutter is to divert rain away from the roof in a controlled manner. Overtime a guttering system will fill with moss, leaves and worn pieces of tile. It's hard to determine how often guttering needs a clean. On large scale buildings a drone inspection is an efficient method to decide.
Porch / Lean-to - Some porches and almost all lean-tos are too high to closely inspect. On a traditional porch, the ridge, its roof to wall flashing and the front facia should be inspected for weather damage. With a lean-to whether it be felt, tile or PVC, checks for UV light damage, cracks, missing or corroded fixtures are important.
Fascia - A long straight board that runs along the edges of a roof. Fixed to the roof trusses its purpose is to support the edging of tiles and providing a fixing mount for the guttering. Materials include wood, PVC and aluminum. PVC fascia boards withstand the elements well, however timber suffers from rot and for aluminum its corrosion. The fascia is also a popular spot for rodents, birds and wasp nests, catching intruders early will prevent costly damages.