From individual slate replacement to full re-slating and lead valley work — here is what we cover.
Individual Slate Replacement
Broken, cracked, or missing individual slates are repaired using a slate ripper to remove the broken unit and a copper clip (tingles) or proper mechanical fix to secure the replacement. We source matching slates — Welsh, Spanish, or synthetic — and dress the replacement correctly to ensure full weathertightness. Copper fixings are used as standard to avoid future corrosion.
Re-Slating Sections
Where nail sickness or widespread slate failure is confined to one slope or section of a roof, we strip that area back to the battens, replace any damaged battens, lay new breathable underlay, and re-slate the section completely to BS 5534:2014 specification. This is a targeted, cost-effective solution that extends the life of the wider roof without committing to a full re-slate prematurely.
Full Re-Slate
When nail sickness has progressed across the whole roof, or the slate itself has deteriorated significantly, a full re-slate is the correct remedy. We strip all slates, salvaging and grading any that are still serviceable, replace battens and underlay throughout, and re-lay to current standards. Where salvaged slate is insufficient, we source matching new or reclaimed slate to complete the works.
Slate Nail Failure (Nail Sickness)
Nail sickness is a gradual process. The first sign is slates beginning to slip — dropping down by an inch or so at their tail end — often without breaking. If caught early, it may be possible to re-nail sections using a wire-nailing technique or fitting slate hooks as an alternative fixing method. Left unaddressed, large numbers of slates slip and fall, exposing the roof to water ingress. Early intervention costs a fraction of the repair bill that follows widespread failure.
Ridge Tile Repairs on Slate Roofs
Ridge tiles on slate roofs are bedded in mortar and pointed at both edges. Mortar cracks and fails as it ages, allowing ridge tiles to lift and water to get into the ridge junction. We re-bed and re-point ridge tiles using high-quality mortar or install dry-fix mechanical ridge systems, which eliminate the maintenance cycle that comes with mortar bedding. All ridge work is carried out with the slates disturbed only as far as necessary.
Lead Valley Repairs
Slate roofs typically use Code 4 or Code 5 lead valleys, which have a design life of 60 to 100 years when properly dressed. When lead cracks, splits, or pulls away at the joints, the valley becomes a significant leak source. We repair or replace lead valleys using properly lapped sections dressed to the required width, with slates cut neatly at the correct tilt angle to ensure good water shedding. See our chimney repair service for lead flashing work.
Pointing and Mortar Repairs
Verge bedding, hip tile pointing, and mortar at abutments on slate roofs require periodic attention. We rake out failed mortar and re-point using an appropriate mix — avoiding overly strong cement mixes that crack and are difficult to remove. Where dry-fix systems are a suitable upgrade, we can recommend and install these as an alternative to ongoing mortar maintenance.
Synthetic Slate Installation
Where natural Welsh slate is not specified or the budget does not extend to it, quality synthetic slates — particularly those manufactured from fibre cement — offer a cost-effective alternative. They are lighter than natural slate, consistently sized, and straightforward to fix to BS 5534:2014 specification. We advise honestly on the visual and performance differences between synthetic products so you can make an informed choice.
