Nannau in Top 10 Heritage Buildings at Risk List
Every year since 2022, the conservation organisation, has compiled a list of the top ten eighteenth- and early-nineteenth-century buildings and landscapes at risk in England and Wales. The list serves to highlight neglected buildings and landscapes that 鈥榗ould and should have a brighter future鈥. The with the strapline 鈥榮top the rot鈥, and includes the Neoclassical mansion of Nannau in Llanfachreth, Gwynedd. The Nannau estate was home to the powerful Nanney and Vaughan families for centuries and a preeminent gentry hub in the old county of Merioneth. This is reflected in the present mansion鈥檚 Grade II*-listed status as a 鈥榟ighly important late-eighteenth century regional house鈥. However, the mansion has changed hands several times since the mid-twentieth century, and has been in an accelerated state of decay since 2020. After featuring on The Georgian Group鈥檚 inaugural list of at-risk buildings in 2022, its return to the list in 2025 is a stark reminder that the mansion continues to stagnate and is at serious risk of being lost altogether unless immediate action is taken.
Plas Nannau is located near the village of Llanfachreth; some three miles north of Dolgellau, a town with which it is intricately connected. It was Cadwgan, son of Bleddyn ap Cynfyn, Prince of Powys, who reputedly built the first recorded house on the site towards the end of the eleventh century, becoming the first Lord of Nannau. The male line of the Nanney family continued unbroken until the early-eighteenth century, but the estate passed to the Vaughan family of Hengwrt through the marriage of the Nanney heiress, Janet, to Robert Vaughan.
Their son Sir Robert Hywel Vaughan (1723鈥1792) was created 1st Baronet and it was he who built the present Plas Nannau 鈥 the fifth house to stand on the site. Sir Robert is believed to have adapted the design for his mansion from a book of house designs by architect P. F. Robinson, adding some subtle variations and Tudor elements. After Sir Robert鈥檚 death in 1792, it fell to his son and successor Sir Robert Williames Vaughan, 2nd Baronet (1768鈥1843) to build the mansion, and he also engaged the professional architect Joseph Bromfield to design flanking pavilion wings and the interior decoration. The mansion was completed in 1805, and has a restrained, Neoclassical appearance with a square plan. Although the pavilion wings were demolished in the 1960s, Plas Nannau is Grade II*-listed as a 鈥榟ighly important late-18th century regional house鈥. It also holds the distinction of being one of the highest country houses in Great Britain, situated at 700 feet above sea level.
Historically, architecturally and scenically, Nannau really matters.
The Georgian period has been described as 鈥榯he golden age of Nannau鈥. Not only was the house rebuilt, but the estate was expanded to 10,164 acres and new carriage driveways, arches, home farms, and lodges were erected. We highly recommend a visit to the , which explores the history of the people, buildings and designed landscapes of the estate, incorporating primary archival material such as photographs, auction catalogues and maps.
After over 900 years of continuous occupation, the family sold Nannau in 1965 and the farming estate in 1975. In 1975, the mansion briefly operated as a hotel, but it has changed hands several times since and its condition has gradually declined; the present owner is believed to have been in possession of Plas Nannau since 2001, by which time it was just a shell of a building. However, decline has accelerated since 2020, when lead was stolen from the roof, leading to significant water damage. In addition to featuring on The Georgian Group鈥檚 2022 and 2025 Top 10 Heritage Buildings at Risk list, Plas Nannau was the Society for the Protection of Ancient Building鈥檚 (SBAB) ; was added to SAVE Britain鈥檚 Heritage鈥檚 Buildings at Risk register in 2023; and was also SAVE鈥檚 . 3,784 acres of historic Nannau estate land, now separated from the house, is .
The historical significance of the Nannau estate was recently highlighted in the publication , launched at Corsygedol in conjunction with ISWE back in 2016. Its author Philip Nannau Williams, a descendant of the Nanney family, tells ISWE that: 鈥渢he fact that Nannau鈥檚 history is so intertwined with major events in Welsh history and culture, led the much-respected late Lord Dafydd Elis-Thomas to pronounce the publication 鈥楢n important book for the Welsh Nation.鈥 The present Georgian Nannau is probably the fifth to be built on the site, the earliest known structure having been erected in the eleventh century by descendants of Cadwgan ap Bleddyn, Prince of Powys. It now stands forlorn, a melancholy sentence for such a noble house, but not forgotten as intense concern for its plight is evident both nationally and beyond.鈥
Thomas Lloyd, ISWE Advisory Board member and author of The Lost Houses of Wales: a survey of country houses in Wales demolished since c.1900, published by SAVE Britain鈥檚 Heritage in 1986, adds that 鈥渢he imminent prospect of this great house being added to the catalogue of Lost Houses of Wales is grim. Moreover outrageous when one considers the statutory protections for listed buildings for long in the hands of relevant authorities. Why has nothing been done? Historically, architecturally and scenically, Nannau really matters.鈥
Urgent repairs are needed to prevent ongoing water ingress and further decline; there is a strong sense that time is running out for Plas Nannau.
Dr Shaun Evans, Director of ISWE, added that 鈥樷榯he prospect of losing Nannau 鈥 a house and estate so bound up in the history, culture and landscape of its locality and Wales 鈥 is a travesty. We must work to carve out an alternative future for this special place and stand ready to work with Eryri National Park Authority and the local community as part of this endeavour鈥欌.
(Authored by Dr Bethan Scorey)