In Runcorn this question usually turns out to be a different one: can a tiled roof become a slate roof? Structurally the answer is more often yes than people expect.
There are two versions of this question in Runcorn, and they have quite different answers.
If your roof is already slate, you are asking what it costs to renew it, and the answer turns on piece count and reclaim — our Chester slate guide works through that in detail, including how natural slate is graded and what the four different things called “slate” actually are.
But on a lot of Runcorn housing the roof is not slate, and the real question is whether it could be. That is what this guide is about.
Changing a covering raises two structural questions: can the roof carry the new weight, and does the pitch suit it.
On weight, going from concrete tile to natural slate is the comfortable direction. Concrete interlocking tile is the heaviest common covering; natural slate is one of the lightest, and fibre cement slate is lighter still. A roof framed to carry concrete tile is being asked to do less, not more.
That does not mean nothing gets checked. The rafters, purlins and wall plates are inspected once the covering is off, because a roof that has been carrying a heavy covering for fifty years may have deflected. But the check is about condition, not capacity.
This is where the conversation usually resolves, and it goes in your favour more often than not.
Every covering has a minimum pitch below which it is not warranted, because at too shallow an angle wind-driven rain is pushed back up under the lap faster than the covering can shed it. Slate tolerates lower pitches than most tiles do, so a roof that currently carries interlocking tile is usually comfortably within slate's range.
The exception to watch for is a shallow addition — a rear extension, a porch or a bay roof — which frequently sits below the main slope and may need a different covering from the rest. Measure it separately rather than assuming it matches.
More than putting tile back, and the difference is mostly labour rather than material.
Against that, two things move the other way. Waste disposal is lighter, because you are taking off a heavy covering and putting a light one back. And the roof you end up with has a materially longer service life than the concrete tile you removed.
An honest answer depends on the house rather than the arithmetic.
| Situation | Our view |
|---|---|
| The house was originally slated and was changed at some point | Strongest case — you are putting back what the building was designed for |
| A period property in or near the older town | Usually worth it, and worth asking the council about the conservation area first |
| A New Town-era house in a street of tiled roofs | It will look different from its neighbours. Some people want that; most do not |
| A semi where only your half is being done | Think hard. Half a pair in slate and half in tile is very visible |
| Budget is the constraint | Fibre cement slate, or a good interlocking tile properly fixed. Do not economise on what goes underneath |
One line on that list is worth pressing: the headlap. Reducing it lowers the number of slates per square metre and makes a quotation look cheaper, and it is not visible in the finished roof. It should be set by the pitch, the slate size and the exposure of the address — never by the price.
Two separate systems. Planning: a like-for-like re-roof does not materially affect the external appearance of a building, so under section 55 of the Town and Country Planning Act 1990 it is not development at all and needs no permission. A visible change of covering can be a different matter, particularly inside a conservation area, where the test is applied more tightly.
Building regulations: where more than 50% of the roof's surface area is renewed, or the work forms part of a major renovation, regulation 23 of the Building Regulations 2010 requires the roof to be brought up to current thermal standards so far as that is technically, functionally and economically feasible — 0.16 W/(m²K) for a roof in an existing dwelling. A patch repair does not trigger it, and neither does a roof over unheated space such as a detached garage.
We will measure the pitch, look at the structure and tell you honestly whether it is worth doing.
New roof installations in Runcorn →
All new roof guides →
New Roof Installations Chester →
Complete new roofs, re-roofing and roof replacement across Chester, the Wirral, Deeside and the surrounding areas.
Tell us about the property and the roof in Runcorn, and we will come back to you — usually the same day.
Prefer to talk? Call 07464 259566 · WhatsApp 0044 7464 259566 · Email Evensbuddy@yahoo.com