Western Slab Mill at Felin Fawr Slate Works is a Grade II* listed building in the Gwynedd local planning authority area, Wales. First listed on 11 April 1990. Industrial building.

Western Slab Mill at Felin Fawr Slate Works

WRENN ID
fossil-cornice-willow
Grade
II*
Local Planning Authority
Gwynedd
Constituency
Bangor Aberconwy MP: Claire Hughes (Lab)
Country
Wales
Date first listed
11 April 1990
Type
Industrial building
Address
Western Slab Mill at Felin Fawr Slate Works, Coed-Y-Parc, Bethesda, Llandygai
OS grid reference
SH 614 663
Coordinates
53.17629, -4.07403
Source
Cadw listing

Also on this page: flood risk · radon risk · weather exposure · detailed attributes ↓

Description

The Western Slab Mill at Felin Fawr Slate Works is a long rectangular building, oriented roughly north-south. It is constructed from snecked rubble stone, featuring hammer-dressed quoins and voussoirs, with a gable-ended slate roof that has slate coping and oversailing eaves. The lower and narrower engine house on the south side is made of slate slab construction. The building has five regularly spaced segmental arched openings with stone voussoirs above deeply recessed doors. There are circular scalloped brace-plates on both walls and large rooflights with glazing bars on both slopes. The engine house includes an infilled pointed arch in the south gable end.

Inside, the mill retains seven massive timber roof trusses of the queen-strut type, with tie-beams supported by open-work cast-iron wall brackets.

Local climate

Western Slab Mill at Felin Fawr Slate Works sits in one of the wettest parts of the UK, with an average of 1,210 mm of rain a year. This makes it wetter than 92% of listed buildings in the UK. Its exposure to wind-driven rain is greater than that of 90% of listed buildings.

It experiences an average of 37 freeze-thaw cycles a year, more than 67% of listed buildings. Of these, 19 follow at least 1 mm of rain in the preceding 48 hours. Average temperatures at this location have risen by 0.3°C per decade since 1991.

Averages for 1991–2020; temperature trend 1991–2025. Figures describe the wider area (a grid cell of roughly 10 km), not the individual site. Contains modified Copernicus Climate Change Service information 2026.

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Nearby listed buildings

  1. Water Wheel House between slab mills at Felin Fawr Slate Works Grade II* 12 m
  2. Eastern Slab Mill at Felin Fawr Slate Works Grade II* 25 m
  3. Foundry at Felin Fawr Slate Works Grade II 41 m
  4. Fitting and Repair Shop at Felin Fawr Slate Works Grade II 69 m
  5. Water Mill & Wheel House at Felin Fawr Slate Works Grade II 73 m
  6. Pont Coed-y-parc Grade II 90 m
  7. New Mill House Grade II 109 m
  8. Dam to SW of former Felin Fawr Slate Works Grade II 178 m
  9. Tanysgafell Grade II 488 m
  10. Tanysgafell Grade II 494 m