Real Slate or Composite: Which Should We Put on Our Roof?

Both look like slate from the street. Here is how they differ once they are on the roof, and where the choice may already be made for you.

Natural slate is split stone, quarried mainly in Wales and Spain. Composite or synthetic slates are moulded from resin and recycled materials, often mineral filled, and some fibre cement slates fall into the same broad group.

Natural slate varies in thickness and colour, which gives a roof its depth. Good composites mimic the riven edge well, but every piece is uniform, and close up that shows. On a period street the difference is noticeable; on a modern estate it often is not.

Composites are lighter and quicker to fix, and most come in consistent thickness so they lay flat without sorting. Natural slate needs sorting by thickness, holing and careful nailing or hooking, which adds labour. Coverage per square metre depends on slate size and headlap, so always check the manufacturer's figure for the pitch you have.

Good quality natural slate can last well over a century, and the fixings usually fail long before the slate. Composites are generally warranted for a few decades by their manufacturers. Our how long does a roof last guide puts both in context.

When there is no real choice

On listed buildings and in many conservation areas, natural slate matching the original is expected, and a composite may be refused. Check before ordering, as covered in our conservation areas guide.

Do composite slates look fake?

From the street, good ones rarely do. Close up the uniformity is visible, which matters more on period properties.

How many slates do I need per square metre?

It depends on the slate size and the headlap required for your pitch. We work it out from the manufacturer's tables for your roof.

Can I use composite slate on a listed building?

Usually not without consent, and often not at all. Natural slate matching the original is normally expected.

Is natural slate worth the extra cost?

On a roof you intend to keep for decades, or on a period house, it usually is. On a modern extension a composite can be a sensible choice.

Weighing up slate for a re-roof?

We can bring samples of both, check what your area allows, and price each so the choice is clear.

Evans Roofing & Maintenance Ltd, Witney, Oxfordshire. Call 07960 482233 for a free written quote.