Can Natural Slate Be Reused When Re-Roofing in Cardiff?

Plenty of older houses in Llandaff, Pontcanna, Canton and Cathays still carry the slate they were built with. When the roof is stripped, owners reasonably ask whether it can be put back. The honest answer is sometimes, and usually only in part. It depends on the condition of each slate, how it was fixed, and how many are lost when it comes off.

What makes a slate worth keeping

A good slate rings when tapped, lies flat, has square edges and shows no flaking layers. Slates that have delaminated, softened or cracked across the nail hole are finished, however good the roof looked from the road. We sort every slate as it comes off. Sound ones are stacked, weak ones are discarded, and you can see the split yourself before any decision is made about ordering replacements to make up the shortfall.

Why some slate cannot go back

Old slates were often fixed with iron nails that have rusted, and the holes can be torn out or enlarged. A slate that has slipped repeatedly is usually damaged at the fixing point and will slip again, however carefully it is refitted. Some slate also carries moss and lichen damage that has worked into the surface. Reusing it in those cases saves little and risks leaks within a few winters, which is a poor trade after paying for scaffold.

Mixing reused, reclaimed and new slate

Where most of a roof is sound, we relay the best slates on the front elevation, which is the one people see, and use matching reclaimed or new slates on the back. This keeps the street appearance and tops up any shortfall. Fibre cement slate is another route where a lighter, more affordable covering suits the house. We will hold samples against the existing slate so you can judge colour and texture before committing.

What else changes when the slate goes back on

Reusing slate does not mean reusing everything else. Battens, underlay and fixings should be new, with stainless or copper nails so the roof is not undone by rusting a second time. Lead flashings, valleys and abutments are also best renewed while the roof is open. Doing them separately later means more scaffold and more disruption, and the old lead rarely survives being lifted.

• New treated battens set to the correct gauge for the slate size.
• Breathable underlay with proper laps and eaves support.
• Stainless or copper fixings, never reused iron nails.

How to decide

Ask whoever quotes to explain how many slates they expect to reuse and what will replace the rest. A vague answer usually means the sorting has not been thought through, and the shortfall appears as an extra later. We will look at your roof from the ground and the loft, then advise honestly. If the slate is tired, we will say so rather than relay it for the sake of appearances. Call us for a proper survey.

Why Choose T & T Roofing South Wales

We're new roof installation specialists covering South Wales, using premium tile and slate roofing systems and honest advice — not a generic call-out. Every job starts with a free quotation and guaranteed workmanship throughout.