Roof advice for Llanelli homes
Slate or tile: what to put back on an old Llanelli roof
Look along an older terrace and you will often see it. A run of grey slate, then one roof in brown or red concrete tile, then slate again. At some point an owner had to re-roof and chose the cheaper covering.
If your slate roof is near the end, you face the same choice. Here is what to weigh up, and what the rules in Wales say.
What the record shows
This swap is common enough to appear in official records. Cadw's listing for a terrace on New Road, built around 1890 to 1900, describes slate roofs and adds that on three of the houses the slate has been replaced in concrete tiles. The listing calls the row, together with a similar one nearby, the best surviving late nineteenth century terrace houses in Llanelli.
So even on a terrace picked out for protection, some roofs were changed. It is fair to assume the same happened on plenty of ordinary streets.
The three coverings compared
Natural slate
Slate is thin, dense and light for the area it covers. It is what the rafters under an old terrace were sized to carry. It lasts longest of the three and keeps the street looking as it was built.
It is also the dearest to buy and the slowest to lay. Checkatrade's roof repair guide prices natural slate work at £150 to £220 a square metre. You can cut the cost by reusing your own sound slates and buying new or reclaimed ones only for the shortfall.
Fibre cement slate
A factory-made sheet cut to look like slate. It is light, so the old frame copes with it, and from the pavement it passes for the real thing when new. The same guide lists it at £90 to £130 a square metre. It does not last as long as natural slate and it weathers to a flatter grey.
Concrete tile
The cheapest covering in that guide, at £90 to £120 a square metre for plain concrete tile, and quick to lay because each tile covers more. The catch is weight. Concrete tiles are much heavier than slate, and the difference is carried by timbers that were never meant for it.
What extra weight does to an old roof
An old roof that has been loaded with concrete tiles can show it. Look along the ridge from across the road. A dip in the middle, or slopes that sag between the walls, are the signs. Inside the loft, rafters may have bowed and the timbers that tie the roof together may have pulled at their joints.
Not every re-tiled roof has trouble. Some were strengthened when the work was done. But if you are buying a terraced house with concrete tiles where the neighbours have slate, a look in the loft is worth the time.
What the rules in Wales say
Building regulations in Wales are set by the Welsh Government. Its guidance on re-roofing says three things that bear on this choice.
First, in most situations re-roofing needs building regulations approval. Second, if the covering is replaced with a different material, and it gives slate to tiles as its example, approval is likely to be needed so that the roof is adequate for structural stability and meets the rules on fire safety and energy efficiency. Third, where the new covering is significantly heavier or lighter, the structure may need modifying or strengthening, and you are advised to check with a structural engineer or surveyor before starting.
Planning is separate. The Welsh Government says you do not normally need planning permission to re-roof, but the materials must match the look of the existing roof as far as possible. Swapping grey slate for red tile does not obviously meet that test. In the Llanelli conservation area the county council says you may need permission to renew or replace a roof covering at all.
Put briefly, like for like is simple. A change of covering means paperwork and possibly an engineer.
Wind, and why fixing matters more than material
Llanelli's roofs face strong winds off the estuary. Any covering will stay put if it is fixed properly, and any will come off if it is not.
For slate that means two nails in every slate, with copper or aluminium nails that will not rust. For tiles it means nailing or clipping them to the pattern the maker sets for an exposed site, not just hanging them on the battens. At the ridge and the gable edges, dry-fix systems screwed to the roof hold better than mortar alone. Ask your roofer how each of these will be done.
For more on the work itself, see slate roofing in Llanelli and new roofs in Llanelli.
Common questions
Is it cheaper to replace slate with tiles?
The covering costs less, going by the published rates for each square metre. But add the possible cost of strengthening the roof, an engineer's check and building regulations approval for a change of material, and the saving shrinks. Reusing your own slate can close the gap from the other side.
Can old slates really be used again?
In many cases they can. A roofer taps each slate and keeps the ones that ring clearly and have sound edges. Those that are soft, cracked or flaking are set aside. How many survive varies from roof to roof, so the quote should say how a shortfall will be priced.
Decide while the roof still gives you time
If the choice is forced on you by a failed roof in January, you will take whatever can be fitted fastest. Looking into it now, with the roof still holding, lets you get the structure checked, cost both routes and sort the approvals without water coming in.
Say what is on the roof now and what you are thinking of. Name your part of Llanelli and a roofer will ring to talk it over.