From Inspections to Repairs: Looking After Slate Roofing
Updated: Jun 15
Both durable and aesthetically pleasing, slate roofs are appealing for a number of reasons. However, to keep your roof in top condition, there are several things you need to keep in mind. Read on to find out everything you need to know about slate roofs and how to care for them.
What are the benefits of slate roofing?
Slate roofs are a popular choice, and it’s not hard to see why. Here’s just a few of their benefits:
Homeowners are typically drawn to slate roofs because of their unique beauty. Slate is a gorgeous roofing material that has been respected by architects for centuries thanks to its classic, clean lines. It’s also available in a variety of colours (such as grey, green, and red), thicknesses, and widths.
Because slate roofs are made of naturally occurring stone, they are highly durable. Unlike other roofing materials, which are highly susceptible to weather events, slate is relatively unaffected by weather extremes, including high winds, high temperatures, or even hail. And because it’s stone, slate is also non-combustible (or fire proof), which provides an advantage in preventing fires from airborne sparks.
Long term investment
Slate roofs are a long term investment that can last many years. Whereas the majority of roofs (specifically those made of asphalt shingles) are lucky to last 20 to 30 years before needing to be replaced, slate roofs are built to last. Depending on where the slate is sourced, you can expect a slate roof to last 40+ years, with the best slate rated to last in excess of 75 years. However, it is also not uncommon for slate roofs to last well past 100 years. Coupled with corresponding long warranties, slate is a great long-term roofing option, especially if you plan on it being installed on a home you expect to live in for a long while.
Thanks to their superior durability and longevity, slate roofs are also relatively low maintenance. Because slate is typically not susceptible to the damaging effects that cause traditional shingles to wear, you won’t have to worry about having to repair or replace loose or damaged shingles. Additionally, slate is extremely dense so it absorbs very little water, keeping out both mould and mildew.
Increased home value
Even if you’re not planning on staying in your house long term, adding a slate roof might still be a good idea if your budget allows for it. Because slate roofs are made of a premium material that is durable, long lasting, and beautiful, having a slate roof can increase your house’s value on the property market.
What should I inspect when it comes to slate roofing?
It’s important to remember that when it comes to slate roofs, there will be certain things you need to keep an eye on. When inspecting your roof, there are several places you should pay particular attention to:
Despite its durability, you’re guaranteed to have a broken or slipped slate occasionally especially if your home is surrounded by large, mature trees or there’s been a particularly bad storm. Individual slates can either be repaired or replaced by a trained slate roofer.
The flashing and gutters are actually the most vulnerable parts of a slate roof, so keeping them maintained is crucial to keeping your slate roof in good shape.
Flashing is a thin, weatherproof material such as copper or galvanised steel that is used around windows, doors, gutters, chimneys or any exterior joint. The purpose of flashing is to keep water from getting under your tiles. Although copper flashings are initially more expensive than galvanised, they also typically last about 70 years compared to galvanised flashings that usually last fifteen to twenty years and require regular painting.
Gutters and downspouts
The purpose of gutters and downspouts is to direct water away from your home. There are basically two types of gutters – box gutters are built into the rafter of your roof, and hanging gutters are attached to the eaves of your home. You’ll need to check to make sure there are no holes or blockages (like leaves and branches) in your gutters and downspouts and that the seams are still intact.
You should study the masonry, the flashing, and the cap or flue covers. If any of these are damaged, it can lead to leaks inside your home.
Sheathing or roof decking
Sheathing is the wood panels or sheet material that is fastened to your roof rafters. The tiles are laid on top of the sheathing, so it’s imperative that the sheathing can withstand the weight of a slate roof and last as long as your slate roof.
Should I repair or replace my slate tiles?
Slate is a natural material with unmatched technical features that will last for years to come. In fact, it’s usually the fixings and the supporting timbers that deteriorate before the slate tiles themselves. But how do you know whether your roof needs a simple repair or to be replaced entirely?
Over time, the corrosion of nails or ‘nail sickness’ causes the slates to slip or split and battens or pegs often decay due to woodworm or rot. Other causes of slate roof deterioration include:
● the delamination of poor-quality slates where they split into layers
● mechanical damage, like wind-lift
● bad slating practice for example the use of thin nails that eventually cut through slates
● the decay of mortar ‘torching’ underneath slates.
Whether you need to repair or re-slate a roof really depends on the extent of the deterioration. This is why regular inspections are essential to spot and tackle problems before they get worse and your repair cost escalates.
Keep in mind what you should be looking out for
When looking for problems internally, water damage to ceilings will probably not be under the problem area on your roof.
Externally looking for broken, slipped or missing slates might be harder to do. But if possible you need to know whether they are all in one area or scattered across the entire roof. If the damage is all in one area, the problem might be with the other aspect, a chimney flashing perhaps, rather than the roof.
Check loose slates for firmness. The best way is to hold a loose single slate at the edge and gently tap it in the centre with a hammer. It should produce a clear ringing sound if the slate is sound. If you hear a dull, dead sound it’s likely that the slate has become porous and is past its usefulness.
When to replace
There may come a time where you may consider replacing your slates. Here are some important things to keep in mind:
● Slipped, broken or missing slates need re-securing or replacing using copper wire or straps (‘tingles’) fixings. Where a patch of slates is re-fixed, (known as a partially renewed batten) they can be secured with nails instead of tingles.
● Obvious repairs aren’t good from a resale point of view. When a building surveyor spots a repair using lead or copper clips, they may decide that the roof is reaching the end of its life and advise it should be recovered.
● A good quality mastic applied in accordance with manufacturers instructions would help you avoid this whilst providing a repair lasting as long as the traditional methods.
● Foam or bituminous-type remedial treatments are not recommended. They reduce ventilation causing the risk of timber decay. Furthermore, when it does become time to replace the roof make the slates reusable.
● Never reverse your old slates. However, the broken slates still have a value so consider storing them for re-dressing and reuse elsewhere on the roof in future.
Professional house roofing and new roofs at ProBuild Contracts Ltd
The experienced team here at ProBuild Contracts Ltd are able to quickly respond to call-outs to fix any damage caused by weather or general wear and tear. Any damage can lead to a leaking roof, causing dampness or pests, so it’s important you seek domestic roof repair as soon as you notice a problem. Our roofing contractors can perform flat roof repairs, garage roof repairs and domestic and commercial roof repairs - so get in touch today to find out how we can help you.