Old Traditional Slate Roofs

Old Traditional Slate Roofs

Slate roofs in IRELAND – Protecting our rich HERITAGE of Traditional buildings.

  • No roof is as pleasing to the eye as an old Traditional slate roof which has been properly maintained or restored.
  • Some people build new houses in the old style with natural stone walls, sash windows and natural slate roofs.
  • Planning regulations normally require old slate roofs to be restored with RECLAIMED natural roof slates.
  • People use old roof slates to match with existing roof slates on an extension or restoration.
  • A reclaimed Bangor or Killaloe roof slate can last far longer than poor quality imported natural slates.
  • There is no cheaper roof than the sound slates on the existing roof –  Re-use your existing roof slates.

Common misconceptions about old natural roof slates:

Valentia slates from County Kerry are Heather colour. So also are old slates from the Blessington slate quarry in Wicklow. Trinity Heather slates came from Newfoundland.  Heather slates from came from Bangor, Maine USA in large quantities in the 1800’s so much so that the Welsh Quarries made representations to the British parliament. Blue Bangor slates came not only from Penrhyn Quarry but also in large quantities from the Dinorwic Slate Quarries. Plum Red Bangors came from Pen-yr-Orsedd, Dorothea and Nantlle Quarries.

Although grey/green KILLALOE slates were the most popular Irish slate, by far, there were also large quantities of blue/grey roofing slates produced at Ahinney, Carrick-on-Suir and Binn Dubh near Roscarbery in Cork.Irish natural roof slates were produced at Glentown in Donegal and in Co Mayo, mostly in small sizes.

These roofs can be very deceptive – while the slates are large and thick and rectangular at the tail, they are often ‘ rag tops ‘ and head nailed. These slates have to be dressed down to a rectangular shape at the top to allow modern fixing by centre nailing.

Two ‘magic remedies ‘ for slipping slates have been offered in the past to unsuspecting clients. Neither one is a good solution.

Slaters have been ‘Turnerising ‘ old slate roofs to prevent slates falling off owing to nail sickness. This involved applying a tar coating to the face of the slates and a fibreglass mesh followed by a further coating. The heat of the sun on the black tar will melt it off over time and the slates then fall off. Some tar remains on the face of the slate and is very difficult to remove making the slate practically useless.

The second remedy was to apply expanding foam on to the backs of the slates, the battens and the rafters to retain the slates in position. Serious condensation problems arose after a period of time and it is difficult to remove the foam coating when salvaging the slates for re-use.

The expected life of those slates is stated to be 30 years. There are many thousands of roofs covered with asbestos slates which will come up for replacement in the coming decades.

There are very strict procedures in place in Ireland regarding the removal, transport and disposal of hazardous waste.

Reclaimed Materials

Old roof slates and roof tiles are salvaged from roofs and brought into our Killoran Slate & Tile depot for processing. Old materials come from various sources. Sometimes people in the demolition business sell the roof slates or tiles to generate immediate cash. Others cannot process because they do not have the necessary Local Authority licencing to dispose of the waste. The majority of old natural roof slates and tiles are traded in from existing buildings when we supply new materials.
We subscribe to the concept of the SALVO CODE. We are careful to only buy from bona-fide suppliers. We always establish the provenance of the roofs making sure that the slates or tiles have not been removed from PROTECTED Buildings.
Customers regularly visit our depot and are always surprised at the amount of rubble at the waste chutes behind our dressing machines. The 2 acres occupied by our salvage tile yard, is built-up ground using slate waste over the past 20 years. Customers are always concerned that unsuitable slates, when salvaged on the scaffolding, may be put back on the roof owing to lack of proper supervision or carelessness.
Every slate going through our works is checked individually for holes in the “weather”, cracks and pollution damage. Only those slates which pass our tests are put into the crate. Damaged slates, if sound,  are reduced to a smaller size on one of our 5 dressing machines. Many old slates were head nailed or fixed with oak pegs. They are called ” Rag Tops “. Rag Tops cannot be centre nailed on a modern roof without dressing down to a rectangular shape. We dress all rag tops to standard lengths and only pack a single length per crate.

Sized quarry roof slates go from 10 x 6 inch  up to 26 x 14 inch. The most demand is for 24×12 and 24×14 but such demand attracts poor quality. If you have to use 24 inch quarry slates it is far better to go for 24 inch Randoms as the quarry slate will be stronger and have a longer life.

People often overlook the fact that 16×8 or 18×9 roof slates give a much more solid roof (more nails per aquare metre) and well as having a beautiful traditional looking appearance.

The largest size generally available in a new quarry roof slate is 60×30 centimetres. That size is often too small or the wrong colour for the roof to conform to Planning Regulations.

Most old roof slates above 26 inch long were usually Random widths. The exceptions being 26×13 inch and 26 x 14 inch. A SIZED roof slate had a side-lap of half  it’s width. RANDOMS require varying minimum side laps dependant on pitch of roof, exposure and slate length.

This is the classic natural quarry slate roof on a large building such as a Church, Courthouse, Castle or Mansion.

The lower courses may start with Randoms 36 inch long  roof slates at eaves and with 2 inch graduations, may finish with Randoms  26 inch long  roof slates at the  ridge. Others could be 22 inch  Randoms slates at eaves and finish with 12 inch Randoms at ridge. Because slates further up the roof look smaller anyway, diminishing courses exaggerate the optical illusion of sizes.

The only roof we supplied with 4 inch diminishing course graduations was ROTHE HOUSE in Kilkenny – there the Graduation was quite visible.

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