Fascia noun
The fascia is the long horizontal board that runs along the lower edge of the roof, directly behind the gutter. It's the face of the eaves — the vertical surface you see when you look up at the roofline from outside. On most UK homes, the fascia is timber or uPVC, typically 150–225mm wide.
Its job is structural as well as aesthetic: it supports the weight of the guttering, closes off the gap at the bottom of the roof, and provides a fixing point for the final row of roof tiles or slates.
- Paint peeling or bubbling — usually the first sign of moisture getting in behind
- Softness or discolouration on timber fascias — indicates rot, often starting at the ends nearest the downpipe where water sits
- Gaps between the fascia and the roof line — allows birds and pests to access the roof space
- Guttering that's pulling away from the fascia — means the fascia fixing points are failing
Soffit noun
The soffit is the horizontal board underneath the eaves — the underside of the overhang between the fascia and the wall. If you stand outside and look straight up at the edge of your roof, the soffit is the surface facing you. Many soffits have small ventilation slots or holes that allow air to circulate into the roof space, preventing condensation.
Soffits are often confused with fascias — the simple way to remember the difference: the fascia faces outward (vertically), the soffit faces downward (horizontally).
- Staining or damp patches — often indicate gutter overflow running back behind the fascia
- Blocked ventilation slots — restrict airflow into the roof space, causing condensation and rot
- Evidence of pest activity — gaps in soffits are common entry points for birds and squirrels into the loft
- Paint failure on timber soffits — inspect for softness beneath, especially at joints and corners
Gutters noun
Gutters are the channels fixed along the eaves that collect rainwater running off the roof and direct it to the downpipes. On a typical UK semi-detached house, the gutters handle tens of thousands of litres of water every year. Most are made from uPVC (modern properties) or cast iron (older or period properties), with cross-sections that are half-round, square, or ogee-shaped depending on the era and style of the building.
A correctly installed gutter is not level — it's set at a slight fall (typically 1:600, meaning 1mm of drop per 600mm of run) so water flows toward the downpipe rather than pooling. Gutters that sag lose this fall, and standing water accumulates at the low point, causing persistent leakage at joints and premature failure.
- Overflow during rain — water spilling over the front edge means a blockage somewhere or a failed joint diverting flow
- Visible sagging — a gutter that dips between brackets is losing its fall and pooling water
- Staining on the wall below joints — a green or brown streak down the wall indicates a leaking gutter joint
- Vegetation growing from gutters — plants (especially moss and grass) in gutters indicate long-standing debris accumulation
- Rust staining on cast iron gutters — surface rust is manageable; deep pitting means replacement is needed
Downpipe noun
Downpipes (also called rainwater pipes) are the vertical pipes that carry water from the gutters down to the drain at ground level. They're typically positioned at the corners of the building and at any change in gutter direction. On most properties, downpipes connect at ground level to either a surface drain or a soakaway.
- Overflow from the top of the downpipe — indicates a blockage in the pipe itself, often at the swan-neck bend where it connects to the gutter
- Separation from the wall — downpipe clips fail over time; a pipe pulling away from the wall rattles in wind and eventually disconnects
- Water pooling at the base — indicates the drain connection is blocked or the soakaway has failed
- Staining on the wall alongside the pipe — often indicates a crack or joint failure in the pipe itself
Ridge tile noun
The ridge tile is the row of specially shaped tiles that runs along the very top of the roof — the apex where the two slopes meet. Ridge tiles are typically half-round or angular in cross-section, designed to cap the junction and prevent water entry at the highest point of the roof. They're bedded in mortar on most UK properties, though dry-fix systems (mechanical fixings without mortar) are increasingly common on newer builds.
Ridge tile mortar has a lifespan of roughly 20–30 years. Failed ridge mortar is one of the most common sources of roof leaks in UK properties, and one of the least visible from the ground.
- Cracked or missing mortar — visible as gaps between tiles and the mortar bed; allows water to track beneath the ridge
- Displaced or rocking tiles — a ridge tile that has moved out of alignment is no longer weatherproof
- Vegetation growing at ridge level — moss establishing itself in failed mortar joints
- Missing ridge tiles — occasionally dislodged by high winds; sometimes visible on the ground below
Hip tile noun
A hip is the sloping external corner where two roof slopes meet — as opposed to a ridge, which is the horizontal top. Hip tiles cover this junction in the same way ridge tiles cover the apex. They require the same mortar bedding and have the same lifespan concerns. Hipped roofs (roofs with slopes on all four sides rather than gable ends) have hip tiles on every corner.
- Same issues as ridge tiles — cracked mortar, displaced tiles, vegetation growth
- Gaps at the top where hip meets ridge — this junction is particularly vulnerable to water ingress
Flashing noun
Flashing is the weatherproof seal at the junction between the roof and any vertical surface — most commonly where the roof meets a chimney stack, a dormer wall, or a parapet. It's typically made from lead (traditional and highly durable), though modern alternatives use aluminium, zinc, or proprietary flexible materials.
Flashing is one of the most critical components of any roof. Where it fails, water has a direct route into the building — and it almost always fails before the roof tiles themselves. Lead flashing has a lifespan of 50–100 years when properly installed; cut-price alternatives may fail within 10–15 years.
- Lifting or pulling away from the wall — flashing that is no longer bonded to the vertical surface admits water at every joint
- Cracking or splits — particularly common in non-lead alternatives after UV exposure
- Missing sections — occasionally removed by wind or disturbed during other work
- Internal damp near chimney breasts or dormer cheeks — almost always indicates flashing failure rather than tile damage
Valley noun
A valley is the internal angle where two roof slopes meet — the opposite of a hip. Valleys form V-shaped channels that carry large volumes of water down the roof. They're typically lined with lead, fibreglass, or purpose-made valley tiles. Because they concentrate water flow from two slopes into a single channel, valley failures can cause significant ingress quickly.
- Debris accumulation — valleys are natural collection points for leaves and moss, which can dam water and cause overflow beneath adjacent tiles
- Visible cracking or lifting in the valley lining
- Damp patches in the room directly beneath the valley — a reliable indicator of valley failure
Pointing noun / verb
Pointing refers to the mortar that fills the joints between bricks or stones in external masonry. It's both a structural component (preventing water infiltration into the wall) and a finish. Over time, pointing erodes, cracks, and falls out — a process accelerated by freeze-thaw cycles, salt air, and acid rain. The process of renewing it is called repointing.
Pointing on chimney stacks is particularly important — and particularly prone to failure — because chimneys are more exposed than the main wall, and thermal movement causes cracking at the joints over time.
- Recessed or missing mortar joints — healthy pointing should be flush or slightly recessed; deep hollows indicate significant erosion
- Cracking along mortar lines — particularly after hard frosts
- White staining (efflorescence) on brickwork — salt deposits drawn out by moisture moving through degraded pointing
- Damp patches on internal walls, particularly on chimney breasts or external walls after sustained rain
Roofing felt noun
Roofing felt (also called underlay or sarking felt) is the secondary waterproof layer beneath the roof tiles. It sits on top of the roof battens and acts as a backup — if a tile cracks or shifts, the felt prevents water from entering the roof structure. Modern felt is breathable, allowing moisture vapour to escape from the loft; older bitumen felt is not, which can cause condensation issues in well-insulated lofts.
Felt isn't visible from outside — its condition can only be assessed from inside the loft. Bitumen felt in older properties can become brittle and crack after 30–40 years.
- Sagging between rafters when viewed from the loft — normal in older felt; more pronounced sagging may indicate saturation
- Tears or holes — particularly around any penetrations through the roof
- Water staining on the felt surface — indicates tiles above have admitted water at some point
Batten noun
Battens are the horizontal timber strips fixed across the rafters that the roof tiles hang from. They're typically 25×50mm or 38×25mm treated softwood, fixed at regular intervals determined by the tile size. The spacing of battens is critical — too wide and tiles flex under load; too narrow and they can't be correctly lapped.
- Rot or softness — particularly at the eaves where moisture can accumulate; visible when tiles are lifted during repair
- This is rarely something homeowners can assess themselves — it becomes apparent when tiles are removed for other repairs
Eaves noun
The eaves is the lower edge of the roof that overhangs the wall — the area where the roof covering projects beyond the face of the building. The amount of overhang varies by property type and era; older properties often have very shallow eaves, while some modern designs have wide overhangs for weather protection. The fascia, soffit, and gutter are all part of the eaves assembly.
Verge noun
The verge is the edge of the roof at a gable end — the sloping sides of a triangular gable wall. Unlike the eaves (which have gutters), the verge simply terminates the roof covering at the side. It's typically finished with a mortar fillet or purpose-made verge tiles to prevent water running down the gable wall. Verge mortar is a common failure point on older properties.
- Cracked or missing verge mortar — allows water to track down the gable wall
- Lifted verge tiles — particularly after high winds
- Damp on the internal face of gable walls — often a verge failure rather than a penetrating damp issue
Chimney stack noun
The chimney stack is the masonry structure that projects above the roof line, containing one or more flues. It's the most exposed part of most UK homes — subject to greater thermal movement, wind exposure, and weathering than any other element. A chimney has four potential failure modes simultaneously: the brickwork, the pointing, the flashing at the base, and the chimney pots and their mortar haunching at the top. This concentration of vulnerability makes chimneys the most common source of roof-related leaks in the UK.
- Cracked or displaced chimney pots
- Eroded or missing pointing between bricks
- Flashing lifting away from the base of the stack
- Visible lean or movement — rare but serious; requires immediate professional assessment
- Damp on internal chimney breast walls — almost always indicates a stack problem
Air brick noun
Air bricks are ventilated bricks built into the external wall at or near ground level, designed to allow air to circulate beneath suspended timber ground floors. Adequate underfloor ventilation prevents the condensation and rot that would otherwise develop in the enclosed void beneath the floor. They're particularly important in properties with suspended timber floors — typically pre-1960s construction.
- Blocked air bricks — often obscured by soil, plants, or debris; a common cause of underfloor rot
- Missing or broken air bricks — allow pest access beneath the floor
- Squeaky or springy floors can sometimes indicate underfloor rot caused by restricted ventilation
Spalling noun / verb
Spalling describes the flaking, crumbling, or breaking away of the surface layer of brick or stone. It happens when water penetrates the surface of a brick, then freezes and expands — forcing off the outer face. Once the protective outer skin of a brick is lost, the softer inner material erodes rapidly. Spalled brickwork is both a structural and aesthetic problem, and typically indicates that the wall has been absorbing more moisture than it should — often due to failed pointing or impermeable surface coatings trapping water inside.
- Fragments of brick face on the ground below a wall
- Rough, cratered surfaces on bricks where the outer face has detached
- Particularly common on older soft-fired bricks on north-facing or exposed walls
- Often accompanies or follows pointing failure — the two problems reinforce each other