Plain-English definitions of the roofing terms you will meet in a survey report or quotation in Beverley, Hull and the East Riding — with what each one means for your property.
This glossary explains the eight roofing terms most often used in survey reports and quotations across East Yorkshire, from nail sickness and flaunching to lead codes and dry ridge systems. Each definition covers what the term means and why it matters locally. Call 0148 290 8437 for a free survey.
If a roofer or surveyor has used a term you did not recognise, it is probably here. Every definition relates to conditions and housing stock we work on across Beverley, Hull and the East Riding. If your question is not answered, call us on 0148 290 8437 and we will explain it plainly.
The corrosion failure of the nails holding roof tiles or slates in place, causing tiles to slip while remaining undamaged themselves. It affects most East Yorkshire property built between 1955 and 1985, where galvanised fixings have now lost their protective zinc coating. Widespread nail sickness means a recover rather than repeated individual repairs.
The sloping mortar fillet on top of a chimney stack that beds the pots and sheds rainwater clear of the flue openings. Cracked flaunching is the most common cause of chimney leaks across Beverley and Hull, showing as ceiling damp beside the chimney breast after rain. Replacement typically costs £180 to £400.
The small projecting lug on the underside of a roof tile that hooks over the batten and holds the tile in position. Where a nib breaks, the tile slips even though its fixing nail is sound — which is why an isolated slipped tile is often a discrete failure rather than evidence of wider nail sickness.
Lime mortar applied to the underside of slates or tiles between the battens on older roofs, used before underlay became standard practice. Most torching on surviving Victorian East Yorkshire roofs has crumbled, leaving debris in the loft and gaps open to wind-driven rain, which is why old slate roofs often leak despite sound slates.
Thickness classifications for rolled lead sheet under BS EN 12588 — Code 4 is 1.80mm and Code 5 is 2.24mm. Code 4 is standard for inland East Yorkshire chimney and valley work. Code 5 is the correct specification for coastal Hornsea and Humber estuary property, where salt air roughly halves lead service life.
A method of fixing ridge and hip tiles mechanically with screws or clamps onto a ventilated ridge roll, rather than bedding them in mortar. Required on new work under the 2014 revision of BS 5534. It removes the freeze-thaw failure that cracks mortar ridges and adds high-level roof space ventilation.
A flat roof build-up placing rigid insulation above the structural deck and directly beneath the waterproof membrane, keeping the whole structure above dew point. It prevents the interstitial condensation that rots flat roof decks from beneath — a common failure on older East Yorkshire extensions built as cold decks.
A single-lap clay roofing tile with a distinctive S-shaped profile, traditional across the rural East Riding on Wolds and Holderness farmhouses, cottages and barns. Its single overlap makes correct mechanical fixing important in exposed positions, and repairs require matched reclaimed material rather than modern concrete imitation.
Roofing quotations vary far more in scope than in price, and the vocabulary is where the difference usually hides. A quote specifying Code 5 lead, a dry ridge system and a warm deck build-up is describing genuinely different work from one that says "new flashings" and "re-bed ridge". Knowing what each term commits the contractor to is what lets you compare three quotations on the same basis rather than on the headline figure alone. If a quotation you have received uses a term you cannot find here, call us on 0148 290 8437 and we will tell you plainly what it means and whether it is appropriate for your property — whether or not you are considering us for the work.
Nail sickness is corrosion failure of the nails holding tiles or slates, causing tiles to slip while remaining sound. It affects most property built between 1955 and 1985. It is diagnosed by lifting tiles and checking the fixings, not by counting slipped tiles from the ground.
Code 4 lead is 1.80mm thick and Code 5 is 2.24mm. Code 4 is standard for inland East Yorkshire work. Code 5 is correct for Hornsea coastal and Humber estuary property, where salt air roughly halves the service life of lead.
Pre-1920s brickwork was built with lime mortar, which is softer than the brick and vapour-permeable. Cement is harder and impermeable, so it traps moisture in the brick, which then freezes and spalls the face. Lime is the correct specification for period Beverley and Hull property.
A dry ridge fixes ridge tiles mechanically onto a ventilated roll rather than bedding them in mortar. It has been required on new work since the 2014 revision of BS 5534. We convert mortar ridges to dry fix during rebedding, which removes the freeze-thaw failure permanently.
A warm deck places insulation above the structural deck and below the waterproof membrane, keeping the whole structure above dew point. It prevents the condensation that rots flat roof decks from beneath, which is a common failure on older East Yorkshire extensions built as cold decks.
A pantile is a single-lap clay tile with an S-shaped profile, traditional on rural Wolds and Holderness buildings. Profiles vary between manufacturers and eras, so a mismatched tile is visually obvious. Repairs need matched reclaimed material sourced against a sample from your roof.
Torching is lime mortar applied beneath slates on roofs built without underlay. On most Victorian East Yorkshire roofs it has crumbled away, leaving nothing behind the slates. This is why an old slate roof can be sound yet still admit wind-driven rain.
Yes. Every survey report we issue sets out findings in plain English, ranked by priority, with photographs. If a term in a report or quotation from anyone is unclear, call 0148 290 8437 and we will explain what it means for your property.