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Master Class: Potato Houses – Part1

Written by Sean Adcock

A large chunk of my formative years as a self-employed dry stone waller were spent on the Ysbyty Ifan estate. In those days I had a workforce, and a number of early projects were at Ty’n y Coed Uchaf (near  Penmachno) in the run up to it being partly opened to the public. One project included the removal of several years, decades possibly, of deposits in the pig sty. I adopted a supervisory role, there were times when having a workforce was actually worth it. Between the house and the pig sty was (still is) what appeared to be a dry stone tunnel, above ground. I was to discover that this was a potato house or ‘clamp’, and that there was another one not far away at Ty Mawr Eidda.

Potato Clamp, Ty’n y Coed Uchaf, Penmachno © Sean Adcock

These potato houses are sometimes known as root cellars, are used to store root crops over winter, protecting them from frost. They are quite popular in North America (USA & Canada) for storing all sorts of root vegetables, although they are rarely dry stone. As the name cellar suggests they were frequently part of the house rather than standing alone in a field. The preponderance of those that were actually cellars probably explains the generic use of ‘cellar’ for virtually all root storage buildings in North America. They are rarer in Britain than many parts of North America primarily because of the relatively mild climate here. In Britain roots were often kept in attics, or even just left to overwinter in the ground (where grown as a feedstuff for stock).

Generally the structures are thick walled (or buried – again “cellars” rather than above ground “houses”) staying cool during hot weather as well as protecting from frost in winter. Andrew Roberts of the National Trust tells me that the Ysbyty Ifan clamps originally had soil piled up over them to keep the frost out, and that they were always built on a bank so that the potatoes rolled to the front to save crawling in to get them, with a slab at the top end removed in order to fill them. As such they represent some intermediate form between ‘houses’ and ‘cellars’.

By and large it seems that at least in Wales clamps were more commonly pits which were dug, the vegetables were then mounded in the pit and subsequently covered with straw and then the excavated soil. Naturally the same ‘pits’ would be used over and over again, becoming very well defined ‘U’ shapes. A trawl of the Coflein1 website un-earthed (sorry) a number of Welsh root cellars, with a particular concentration of around 30 pit types around Troed yn Rhiw in Ceredigion (between Lampeter and Aberaeron). Several images of the pits are available at
There are two main concentrations of 14 (SN7663566710) and 12 (SN7647066342) with other scattered examples in the area. Both are quite extensive, set out in lines of around 59 and 43 metres respectively and varying from around 4.5-6m by c.1.5m each. The Coflein interpretation is that varying alignments, and/or the fact that they seem to overlie each other at points, means that they are not necessarily contemporaneous.

An obvious upgrade to a simple pit would be a stone lining and my ‘trawl’ revealed a few. The Coflein site can at times be compared to needles in haystacks. Separate searches for “root” and “clamp” probably covers all they have. Stone structures are perhaps not surprisingly apparently much rarer, although neither of the fine Ysbyty Ifan candidates appear to be listed on Coflein, so who knows what’s out there?

The Coflein results are not always clear as to whether or not stone is involved. The list below comprises those that obviously do, and if you’re passing photos would be appreciated! Unlike many of the plain earth mounds, there are no photos of these on the site. I reproduce most of the Coflein entry for each, more or less verbatim appending grid refs taken from the site. The date at the end is the record date. The web
address for each record is correct as of 13.08.2012

Gwenlas, Powys. SO11438039
Semi-subterranean stone-built chamber set into the bank above Gwenlas farmhouse. Largely destroyed (noted 1990). (2002). Potato Clamp, Ty’n y Coed Uchaf, Penmachno © Sean Adcock

Cornel, Nantmel, Powys. SN98226365
Stone-lined and slab-roofed chamber for potato storage covered with an earth mound. 2001.

Egryn Abbey, Dyffryn Ardudwy, Gwynedd. SH59582029
Semi-subterranean potato clamp on the SE. side of the farmstead. The chamber is about 20 feet in length, but partially ruined. (2003) The potato clamp was restored by the National Trust in 2007 with the addition of a metal bar to strengthen the roof slabs, and a wooden door. (2008)

Gylfach y Rhiw, St Harmon, Powys. SN97407199
Permanent semi-subterranean potato store built into an earth bank. The narrow rectangular chamber inside the mound is stone-lined and measures 11 feet long, 3 feet wide and almost 5 feet high, giving a storage
capacity of nearly one ton (noted 1989). (2005)

Sunnybank, Llanbadarn Fynydd, Powys. SO07807881
Stone-lined dug-out potato clamp, covered by zinc sheeting. A late example. Noted in 1990. (2001)

Home Farm, Leighton, Powys. (SJ2430505229).

Basement entry to root store in northwest corner of complex, from the south Crown Copyright: Royal Commission on the Ancient and Historical Monuments of Wales .

There is one “root house”, a very grand, stone mortared structure, covered in some detail by Coflein, with a number of photos.

The roothouse was built in the early 1860s and was the last building to be erected at Leighton Farm, the model farm of the Leighton Estate, developed after John Naylor had acquired the Leighton Estate in 1846-47.

The roothouse consists of two parallel, single-storey ranges with vaulted tunnels beneath, constructed of brick on a random rubble basement, with roofs of slate on the outer pitches and corrugated asbestos-cement and glazed panels on the inner pitches. The south gable ends face the road and have wide round-headed doorways (the doorway to the right has later been lowered) with raised original vertical sliding gates in front of inserted sliding doors. The east side wall has ventilation holes in lozenge patterns and an inserted door at the south end. The north gable ends also have ventilation holes laid out in lozenge patterns. In the random rubble basement wall beneath, are openings to six brick-vaulted tunnels (one now concealed by an inserted door).

Internally is a row of central posts, between which has been infilled with concrete blocks at a later date, dividing the interior into two units. The west range has a roof with king and queen posts and raking struts. The east range is said to have a sloping cartway, while the west range has a modern concrete floor but the shafts through which the roots were passed can be seen in the vaulted tunnels of the basement. 9source; Cadw listing database). ( 2008).

Having graduated to houses I should mention an interesting little booklet “An Illustrated Guide to Stone Antiquities on The North Yorkshire Moors” by Elizabeth Ogilvy which I acquired many years ago and includes an entry on “Potato Houses”. I have still to actually get to these, however I dispatched our North Yorkshire (formerly Ireland) correspondent. Okay sometime contributor David Perry kindly agreed to visit the houses noted by Ogilvie and send some photos and comments.

The content below was copied with the generous permission of the author Sean Adcock.  This Master Class article originally appeared in the Summer 2012 issue No. 26 of Stonechat, produced by the North Wales Branch of the Dry Stone Walling Association of Great Brittan

This entire issue of Stonechat, and many more, are available at  Thank you to Sean for allowing us to provide this content, and please donate to The North Wales Branch.

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