What Is the Main Disadvantage of a Slate Roof?

Cost is the drawback people feel first. A slate roof is dear to put on, and the quote usually lands well above the figure for a concrete tile roof. The MyJobQuote average of around £7,800 (Oct 2026) is only a national guide, because roof area, pitch, chimneys and access all move the total for a particular house.

Does slate pay you back later?

It can. CORC, the Confederation of Roofing Contractors, puts it as slate lasting 100 years or more when well maintained. That is a trade body's typical range and never a promise, and it holds only while the nails, battens and flashings underneath keep pace with the stone. A tired fixing can give up long before a good slate does.

The fairer comparison is cost per year of service, not cost on day one. Anyone planning to stay in the house for the long term may find slate comes out ahead on that measure, while a seller who moves in two years may never see the benefit. Our guide to what a slate roof costs and how long it lasts set out both sides in more depth.

Natural slate is stone, and it loads the roof structure more than a light sheet covering would. On a Victorian house built for slate that causes no trouble at all. The difficulty starts when a lighter covering is swapped for slate, or when slate goes on timbers sized for something else.

When does extra weight need approval?

The Planning Portal says a replacement that makes the covering 15 per cent or more heavier needs Building Regulations approval, and it urges you to have the structure looked at first. That sits under Building Regulations, not planning permission, and the person to ring for a ruling on your own rafters is building control.

Weight shapes the job itself. Stripped slate is heavy to lower, stack and take away, so the roofer plans access, scaffold and waste before a single slate comes off. That planning is paid for in the price, which is a second reason slate costs more than a quick recovering job with a lighter material.

If you are unsure what your rafters were built for, ask for that to be checked at the survey.

Slate splits along its grain. A boot in the wrong place can crack a slate across its width, and the break often hides under the course above where nobody can see it. You may only learn of it weeks later, from a damp stain on the ceiling below.

Why does that make upkeep harder?

Every call-out, every aerial fitter and every neighbour with a ladder becomes a risk to the roof. Slate is not hard to look after, but it does mean checking it from the ground on a dry afternoon, or letting a roofer go up with a roof ladder, a ladder hooked over the ridge that spreads their weight across several slates.

That is a real drawback where chimneys, dishes or solar fittings invite regular foot traffic, since each visit puts a few more slates at risk. Plan the access before the work starts, and ask any tradesperson how they will reach the roof without standing on the slate itself. Our answers on walking on a slate roof and why slates slip or crack explain what happens under a boot.

Slate leaves little margin for error. Each slate hangs on two nails or a hook, and the slater must lap it correctly over the course below. The slate maker Cupa warns against hooks on any slope below 25º, and points to BS 5534 for a 20 degree minimum pitch for natural slate. A fixer who skips those checks hands you a roof that leaks in its first winter, and the fault may take months to show.

Is it hard to find the right roofer?

Good slaters take time to find, and repairs call for matching the colour, size and thickness of the old stock. On a listed house, or any house in a conservation area, the consent route matters too, so ask about it early. Replacement slate that looks wrong from the street can also cost you when you sell.

None of this argues against slate. It argues for hiring carefully. Before we price any slate roofing job we read the roof, and the quote that follows is one written total. Ring or message us with how old the slate is and what has gone wrong, and our first visit will weigh slate against the alternatives for your house.