Slate Roofs: To Repair or Replace?

Though slate is one of the best materials for roofing in the market, it is often the case that even the most durable of roofs find themselves in need of repair. Repairing a slate roof is possible but in some cases, even a little damage can mean roof replacement is the best long-term solution to a problem. In any case, it is essential to know whether repair or replacement is the best order of business.

  1. Slipped Slates/Cracked Tiles

Dislodged, broken and missing tiles of slate often lead to roof leakages during the rainy seasons. To repair a slate roof suffering from a few damaged tiles is a relatively simple task, however in older roofs, it is possible that a lack of underlay (which provides cover from the outside elements) may require replacement. Repairing a slate roof is often a small job and thus less cumbersome, whereas replacing an entire slate roof is more expensive.

  1. Sagging Roof Slopes

Depending on the structure of the building, sagging roof slopes are quite common and easily fixable. Often, a slight settlement is to be expected in gable ends or party walls, however if the movement is minimum, basic carpentry can be used to repair slate roofs. It is only in the case of more extreme sagging that a structural engineer may need to be consulted to ensure that the basic foundation of the building is not compromised. Such instances include damage caused by:

  • Weak roof timbers, where the slate tiles may be slipping due to the damaged rafters underneath them.
  • Roof spread, which causes the roof to dip towards the middle due to uneven spreading of rafters.
  • Environmental damage via insects such as termites etc., or rotting due to excess rainfall.

Where access is relatively easy and only minimum repair work is required, the venture is relatively cheap. However, in cases of extreme damage where the rest of the building may also need repair, the cost of repair of a slate roof will be higher as the entire part of the building may need to be replaced.

  1. Defective Pointing

There are a variety of ways to identify defective pointing and whether that requires you to replace or repair a slate roof:

  • Gaps and loose mortar at various points along the roof
  • Slipped ridges
  • Leaks and damp timbers

The risk with defective pointing is fairly low, however if left unattended for a long period of time it could cause the roof to collapse. Due to this, it is essential to address the problem immediately to stick to repair rather than replacement. The most common problems can be fixed at a relatively low cost. These include:

  • Eroded mortar joints
  • New hip irons
  • Mortar mix repair for loose tiles

Depending on the number of tiles that require fixing, the price may go up, including a service charge.

  1. Slipped/Missing Tiles (more than 10)

While many old buildings, even in the best of conditions, may have some tiles missing, it is often when the number goes up that concern grows. If more than 10 tiles are slipped or missing, it may still be possible to simply repair a slate roof, but more often than not it is necessary to replace the entire thing.

A complete re-roofing can be expensive, but is often required since repair becomes more difficult when more tiles are lost. A repair job should include:

  • Stripping of all old materials
  • New slating
  • New ridges and hip tiles
  • Verges/undercloak pointed
  • Double eaves courses pointed

Depending on the material used, the price may go up, though natural slate is the more favourable material. Quotes are available for other tiling, such as clay, concrete etc.

If your slate roof is in need of a little TLC, get in touch today. 

All roof work undertaken

Fully qualified for heritage tiling & repair

Fully qualified in traditional roofing works

Contact Us

Make an Enquiry