It’s not unusual to spot small gaps where one or two tiles or slates have slipped or cracked. In most cases rain penetration is only likely to become a serious problem where several adjoining slates or tiles have slipped, are broken or missing.
Most roofs built post-1950s also have a layer of underlay felt providing a secondary defence. Any wind-blown rain that penetrates under the slates or tiles should be safely channelled down to the gutters. However, older roofs were generally built without any underlay.
The odd dislodged or missing tile, is often caused by storm damage, or people walking on the roof for TV aerial/satellite dish installation. A missing tile or slipped slate is not usually a critical defect, but repair should not be left for too long, especially on roofs clad with larger interlocking tiles (with less overlap), and on older roofs with torn, sagging or non-existent underlay.
Gaps between adjacent tiles/slates near gable ends or party walls can also develop where the roof slopes have settled more than the walls. Spaces of up to 10mm either side of each tile are not normally significant, as the lapped tiles underneath cover the gap.
If there are only a few slipped or missing tiles or slates, they can usually be re-fixed or replaced fairly easily. On shallow pitched roofs (common on 1970s properties), the underfelt can start to sag, diverting rainwater down wall cavities. This may mean the lower layers of under-felt need to be stripped, replaced and re-battened.
Damaged Roof Tiles
Tiles can be prone to localised defects such as broken tile nibs. Even long-lasting plain clay tiles can eventually start to erode and crack across the middle or spall in layers. It is relatively easy to replace tiles because, unlike slates, they are typically only nailed every fourth or fifth course.
How we remove a broken tile:
- We lift the two tiles above it with wooden wedges.
- Use a bricklayers trowel to raise the damaged tile off the batten.
- Carefully slide it out.
- Ease a replacement tile in to its place.
- Hook the nib over the batten.
- Slate Roof Repairs
Slate is a very durable natural material, but old fixing nails are prone to corrosion.
Old slates can crack across their width and middle, or even start to flake in layers.
Each slate is nailed to a batten, and slate sizes vary, they are more difficult to lift out and replace.
Slipped slates can be refixed using copper or aluminium alloy nails.