Slate roofs are desirable for their exceptional lifespan - often lasting over 100 years - yet even the sturdiest of slate installations can develop issues over time. In many cases, targeted repairs (such as swapping out cracked slate tiles) can quickly restore your roof’s integrity without breaking the bank. However, in other scenarios, an entire slate roof replacement might be the best solution for persistent issues.
In this article, we’ll discuss how to repair a slate roof, identify when an entire replacement might be more beneficial, and help you understand the costs involved. If you’ve noticed an issue that needs fixing, please don’t hesitate to contact our slate roof repair experts!
Warning Signs Your Slate Roof Needs Repair
Fortunately, for most roofing issues, there are visible indicators that something is wrong, including:
- Leaks in the ceiling.
- Cracked or broken slate tiles.
- Loose, dislodged, or missing slate tiles.
- Moss or algae growth on the roof surface.
- Damaged flashing around chimneys or other penetrations.
- Excessive slate shedding.
- Sagging roof ridges.
- Rusty, loose, or missing fixings.
Common Issues That Lead to Slate Roof Damage
There are several issues that you should be aware of that can cause your slate roof to degrade faster than expected, such as:
Poor Quality Slate Tiles
Although some slates are particularly durable, such as Welsh, Cornish, or Brazilian slate, not every type is as resistant to different weather conditions. Cheaper slate has different temperaments, leading to a shorter lifespan and more frequent repair needs; therefore, we recommend opting for the highest-quality slate, like that installed by Empire Roofing.
Cracked or Damaged Slate
This relates to the above, as cheaper slate is often more brittle. Cracked or damaged slate tiles are prone to water ingress, allowing rainwater to seep between your roof’s outer protective layer. Fortunately, isolated areas of cracked slate are easy for professionals to replace.
Storm Damage
Strong winds and heavy rainfall are a common cause of roof damage, as seen during recent storms here in the UK. Slate roofs are one of the most weather-resistant options you could have, but even the strongest of slate can be affected by extreme weather conditions.
Poor Installation
Poorly installed slate is more prone to damage, since the tiles have been improperly attached to the roof’s surface. This is why you need to have your slate roof installed or repaired by professional roofers who have experience working with slate, like our Empire Roofing team.
Wear & Tear of Fixings
Over time, the metal fixings that secure slate tiles, such as nails, hooks, and battens, can corrode or loosen due to moisture, temperature swings, and wind stress. This can cause individual tiles to slip out of their proper alignment, leading to a greater risk of leaks.
How to Repair a Slate Roof
Before we begin discussing how to repair a slate roof, we’d like to make it clear that you should never climb on your own roof. This should always be left to the professionals, since we have the equipment to stay safe during the repair process!
Typically, this is how the roof repair process looks:
1. Inspect and Identify Damage
- Assess the roof’s perimeter and scan from ground level for missing, cracked, or slipped slate.
- Note areas where flashings or fixings look corroded or loose..
2. Remove Broken Slate Tiles
- Gently lift the two slates above the damaged one, sliding a slate ripper or flat bar under the hooks or nails.
- Cut or pry out the fasteners securing the broken slate.
- Slide out the damaged piece.
3. Prepare Replacement Slate
- Measure the old slate’s size and thickness.
- Cut the new slate to fit using a slate cutter or an angle grinder with a diamond blade.
- File or rout the hole for the nail or hook to match the adjacent tiles.
4. Install the New Slate
- Slide the replacement into position, ensuring it sits flush with the surrounding tiles.
- Secure with stainless-steel or copper nails/hooks: drive the nail into the batten at a slight downward angle, then embed the head under the slate above to conceal and protect it.
- Gently lower the two slates above back into place.
5. Seal and Weatherproof
- Apply a thin bead of roofing sealant under the replacement slate’s top edge to help prevent water ingress.
- Check and reseal any nearby flashings, hip, or valley details as needed.
6. Clean Up and Inspect
- Remove all debris and old slate fragments from gutters and the ground.
- Perform a final roof walk-through to ensure all tiles are secure and aligned.
Of course, this is just an example of a general process for a simple repair job. As professionals, we can identify when a simple repair is needed, or if there may be additional structural damage or hidden damage that an untrained eye might not find, which might call for more extensive roof repairs or a slate roof replacement!
Slate Roof Repair Costs
Understandably, roof repairs are much cheaper than replacements. However, the cost to repair a slate roof depends on several factors, such as:
- The size of the area that needs to be repaired.
- The type of slate you’re currently using.
- The installation complexity.
- The area of the country in which you live.
Compared to other roofing materials, slate is a premium choice and therefore is the most expensive, although it can help you save money in the long run due to its durability and insulation benefits. For a repair area of one square metre, Welsh slate will cost you £180+, Spanish slate is priced at £75+, and synthetic (man-made) slate is valued at £20+.
When to Replace Your Slate Roof
Unfortunately, not every scenario can be fixed with a simple repair. Here’s how to tell when your slate roof could benefit from a total replacement:
- More than 20% of slate tiles are damaged or missing.
- Persistent leaks despite targeted repairs and sealing.
- Deteriorated or rotted roof decking that is visible from the attic.
- Flashings beyond repair (repeated failures at chimneys, valleys).
- Rusted, corroded, or snapped fixings in multiple places.
- Sagging or structural deformation of the roof deck.
- Severe discolouration of the tiles.
Slate Roof Replacement Costs
The total price of a slate roof replacement for a standard 4-bed home (100m²) roughly looks like this:
- Budget Slate (Synthetic Slate): £6,000 to £9,000
- Mid-Range Slate (Such as Spanish or Brazilian): £8,500 to £13,500
- Premium Slate (Such as Welsh or Cornish): Upwards of £18,500
Contact Us For Professional Slate Roof Repairs & Replacements
If you’ve noticed any of the warning signs that your roof needs repairing or replacing, don’t hesitate; the sooner you get your roof seen to, the cheaper it will be to find a lasting resolution!
At Empire Roofing, we offer professional repairs and replacements for all kinds of roofing materials, from slate to terracotta tiles, keeping your home safe and dry across all seasons. Please contact us today to discuss your roofing issue, and we’ll be more than happy to help find the best solution.
