This is a record made for Snowdonia National Park of how the roof of Penmaen Cottage near Dolgellau was re-slated.  The conservation work and a training programme was supported by the Dolgellau Townscape Heritage Initiative, Snowdonia National Park Authority, the Heritage lottery Fund. CADW and the National Park’s Sustainable Heritage Fund.  The slating was carried out by Jordan Heritage Roofing.

The record is in three parts: 

  1. investigation, looking at the roof details as it was dismantled;

  2. thinking about the details and whether they had been successful and if there was any reason to change them, and

  3. re-slating

Recording the slating involves measurement of the slate lengths, their margins and the gauging for each course.  Inevitably by the time such work is carried out the slating has usually deteriorated - the laths or battens may have deformed or moved down slope and the slates may have slid out of position.  So the objective is to decide the slater’s intention when the roof was slated rather than to decide what the original laps and gauges were precisely.  For this reason it is usually sufficient to work to the nearest 1/4 inch or 5mm.

The slating may give some indication of a date for the roof from the types of nails used but the best evidence for how the roof and the building has evolved is more likely to be seen in the roof structure.

These videos are free to download or they can be embedded in a website.  They should not be altered in any way and the source,, and the copyright owner, Awdurdod Parc Cenedlaethol Eryri / Snowdonia National Park Authority, must be acknowledged.

Links to topics discussed in these videos

  1. -How roofs work

  2. -Lapping systems - slating in thirds

  3. -Random slating

  4. -Valleys

  5. -Verges

  6. -Practical Building Conservation






Charted Institute of Building Awards 2015

Excellence & Quality Winner

Jordan Heritage Roofing for Penmaen Cottage

“... the judges unanimously agreed the winner showed, through their entry, a high level of skill in carrying out the work and adhering to a quality regime set by CADW, thereby creating a worthy entry complying to both excellence and quality for this category.”

National Federation of Roofing Contractors

National Awards 2015

Heritage Roofing

Penmaen Cottage by Jordan Heritage Roofing