Claerwen Dam, including attached footbridges is a Grade II listed building in the Powys local planning authority area, Wales. First listed on 31 July 1995. Dam.

Claerwen Dam, including attached footbridges

WRENN ID
grey-rafter-dust
Grade
II
Local Planning Authority
Powys
Constituency
Brecon, Radnor and Cwm Tawe MP: David Chadwick (LD)
Country
Wales
Date first listed
31 July 1995
Type
Dam
Address
Claerwen Dam, including attached footbridges, Rhayader
OS grid reference
SN 869 636
Coordinates
52.25931, -3.65749
Source
Cadw listing

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

Description

Claerwen Dam is a masonry-faced concrete dam, approximately 56 meters high, that supports a viaduct on 13 elliptical arches, featuring stone parapets. The central arch of the viaduct is broader and carries a viewing platform with a balustrade. The end piers of the platform extend down to the full height of the dam, framing a stepped spillway. At the base of the dam, there are two buttresses with doorways that are connected by diagonally set bridges over the pool at the foot of the dam. At both ends of the dam, there are stepped spillways with parapet walls that broaden as they descend. The walls turn to frame a channel in front of the foot of the dam, which is spanned by a stone bridge with two segmental arches and iron railings.

Local climate

Claerwen Dam, including attached footbridges sits in one of the wettest parts of the UK, with an average of 1,230 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 86% of listed buildings.

It experiences an average of 57 freeze-thaw cycles a year, more than 97% of listed buildings. Of these, 35 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.

More on this building

Sign in or create a free account to unlock:

  • No EPC on record for this property
  • No sale records on file
  • No related consent applications matched
  • Detailed attributes — period, style, materials, features
  • Flood risk assessment
  • Radon risk assessment
  • Weather exposure and heating demand — rain and frost month by month and year by year, wind direction, solar and humidity
Create free account

Matched applications, energy data and sale records are assembled automatically and may contain errors. Flag incorrect data.

Similar buildings

The closest matches to this building from all 493,000 UK listed buildings, by architecture, period and materials.

See all similar buildings →

this building   1 similar   nearby listed buildings

Nearby listed buildings

  1. Claerwen dam, including attached footbridges (partly in Rhayader community) Grade II 95 m
  2. Gauge House at Claerwen Reservoir Grade II 149 m
  3. Road bridge below Claerwen dam (partly in Rhayader community) Grade II 232 m
  4. Llannerch-y-Cawr Grade II* 3.9 km
  5. Carreg Ddu Viaduct and Submerged Dam Grade II* 4.1 km
  6. Foel Valve Tower Grade II* 4.1 km
  7. Caban Coch Dam (partly in Llanwrthwl community) Grade II* 5.5 km
  8. Caban Coch dam (partly in Rhayader community) Grade II* 5.5 km
  9. Craig Coch Dam & Valve Tower Grade II* 5.6 km
  10. Penygarreg Dam & Valve Tower Grade II* 5.6 km