When it comes to your roof, slate looks great but it isn’t cheap. A single natural slate roof tile costs £3.13 at Travis Perkins, while a clay one is less than £1. Don’t let this put you off buying a house with a slate roof, though, since the slate tiles are almost twice the size of the clay ones, which means you will need fewer when it comes to repairing or replacing them. You will need around 20 slates per square metre, or 60 clay tiles, so, on a 100 square metre roof, you will need to budget £6,260 for slate, and £5,820 for clay. The difference is around 7% and excludes any extras or labour. Exact sizes will be affected by the footprint of your home and also the pitch of the rafters in your roof space.

Unless you are on a tight budget, replacing like with like is usually the best option – and your local authority might make it a condition of signing off the work, too.

Applications and approval

Building regulations vary between the devolved administrations but, as a rule of thumb, authorities are less likely to authorise work that, in their opinion, would be out of keeping with its surroundings. It is not only when working on buildings with listed status that you need to be mindful of the law, either.

The Building Regulations 2010 cover not only new builds and extensions but, among other things, work to “replace roof coverings on pitched and flat roofs.” Approval will consider both the quality of the work and the materials used. You should apply for approval before commencing work, either direct with your local council or through an approved contractor.

If your work covers less than a quarter of the roof then, according to Planning Portal, you would normally be exempt from seeking approval unless your choice of material was significantly different to that already in use. This isn’t just because the council – or your neighbours – want to stifle any changes to the look of the neighbourhood: it is also a safety issue. As the Portal explains, ‘if the existing roof covering is to be replaced with a different material to its original; for example, slate to tiles; then approval under the Building Regulations is likely to be needed to ensure the roof will be adequate in terms of structural stability (applicable where the replacement tile will be significantly heavier or lighter than the existing), and also meets requirements in respect of fire safety and energy efficiency.’

If approval is granted, it could therefore be on the specific condition that underlying structural elements, like trusses, are replaced at the same time as the slate. This could wipe out any savings you make by switching from slate to clay tiles.

Alternatives to slate

But it is not all bad news. Subject to approval, it is possible to achieve a similar result with artificial slate. While this looks like the real deal, it is lighter than natural slate, so its use is less likely to require additional work on trusses and other internal supports. It is also considerably cheaper, at around £1.50 for a 600 x 300mm tile, which compares favourably with the £3.13 you would need to budget for a 500 x 250mm slate.

Fibre Cement Slate, an alternative to plastic-based artificial slate can be cheaper still, and a significant time saver, with 600 x 300mm panels just 6p more expensive than single clay tiles. These are pressed to mimic several slates in a single sheet, reducing not only the bill of materials, but the cost of labour, too.

There are plenty of options out there. Our tip would be to check the building regs and your bank balance before you start!