EAST PEEKE FARM BARN

WRANGATON DEVON

 

5.10.15

It is believed that East Peeke Farm barn was remodeled in about 1830-40 and the new roof shown here constructed.  An 1849 specification for similar slating but for single size 18 x 9 inch slates is available here >

In the South Hams district of Devon, between Exeter and Plymouth there is a system of slating which uses small, scantle, slates dry laid and triple lapped.  At the eaves, verges and hips larger, rag, slates are used which are better able to resist wind loads than the scantles.


In 2015 a partial survey of a good example of this fast disappearing, regionally distinctive, vernacular form of roofing was carried out for Historic England South West Region and Dartmoor National Park.  It was funded by the Building Conservation Research Team of Historic England.


East Peeke Farm Bank Barn is typical of the South Hams barn type which has an upper threshing floor above animal housing.  It is aligned end on to the bank with a large door for loading hay or corn and this dictates to form of the roof.  The tall door requires a gable end but above this the roof is hipped because hips are less of an obstruction to wind and therefore less likely to suffer damage.  Hips however are not ideal for scantle slates.


The barn is thought to be C18 but to have been re-roofed in about 1830 - 40.  This was part of a general remodeling to incorporate mechanised grain processing.  The long walls had previously bowed and this may have caused the existing roof to fail or at least leak.  The roof structure was renewed and the slating accommodates the curve of the walls.

the eaves formed with rag slates known as mounters or prickers; 

the main area of small slates laid triple lapped;

verges formed with rag slates

The slating is laid to 5/8 x 1/4 inch riven softwood laths, iron nailed on 1 3/4  x 1 5/8 sawn rafters on two purlins on seven trusses.  The north-west side is concave being approximately 1 3/4 inch lower at the mid-point of the rafter.  The rafters foot onto the rear of a wall plate which is set forward onto the outer face of the wall to provide tilt for the slating.

and half hips also of rags.

MAIN SLATING

The scantle slates are 15 to 6 inches long and 16 to 3 inch wide and hung on softwood pegs to riven softwood laths. The whole of the slating, except over the walls, is torched with no evidence of head or tail bedding.  It is dry laid in the three and a half pin scantle system in which the gauging of the laths is determined by dividing the slates’ lengths by 3.5 which means each course overlaps the third course below by one seventh of the length. 


As is normal in random slating the gauge is reduced when a course of shorter slates is introduced to avoid a course of longer margins over a shorter one and to ensure there is an adequate head lap.  The smallest side lap seen was 1¼ inches which would normally be regarded as very narrow and potentially a source of leaks. Because of the extra lapping in three and half pin slating, it is not a problem.


Backers - narrow slates, marked red, are laid onto wide slates known as wide butts.  These increase the number of slates in successive courses to provide for the greater number of narrower slates in the upper courses.

It was not possible to check the origin of the slates but they probably came from one of the South Hams quarries. 


The slating is in four parts:

EAVES

The eaves are formed with 18 and 19 long mounter slates 30 to 10 inch wide nailed directly to the rafters as is normal for rag slating.   They are underlain with 15 inch slates.  The two courses above the eaves slates are laid double lapped at one third lap.  The slating overhangs the wall face by 6 - 7 inches without gutters.  This would cast water well away from the wall to prevent the mortar being eroded. 

The term scantle slating is used for any system which uses small slates. 


This is confusing as it fails to distinguish between normal double lap slating with small scantle slates and the three and a half pin system with similar slates. 


It is clearer to describe the latter as either dry laid three and half pin scantle or wet laid three and half pin scantle. 


Dry laying is more common in Devon and wet laying in the more exposed parts of Cornwall.

HIPS

The hips are also formed with rag slates laid with their larger dimension horizontal.  If a hip slate is cut to a point or even with just a narrow top edge there is a risk that it will be lifted or snapped by the wind.  Laying the slates widthwise ensures there is a decent width at the top corner to prevent this.

The slating at the eaves on both sides follows the bow of the barn walls but it is gradually eased upslope until at about course twelve the courses are roughly parallel to the ridge.  It is unlikely that the change from ridge parallel to eaves parallel slating could have happened because of movement in the structure.  It suggests rather, that the coursing adjustment was deliberate and therefore post dates the bowing of the walls.

VERGES

Verges and hips are exposed to strong wind uplift forces which top hung scantle slates are ill equipped to resist.  This problem is overcome by using large rag slates into which two or three courses of scantle slates are blended.  To achieve a level surface the rags slates need to be twice or three times as thick as the scantle slates.  On one course for example the scantles are about 7 mm thick, with three laid against a 24 mm thick rag.


Great skill is needed to lay two or three scantles against a rag slate without creating inadequate side, head or shoulder laps.  To do this the slater selects each slate carefully but it is sometimes impossible to achieve. The bottom image shows how the slater overcame this problem by inserting a shadow slate over the vulnerable area.  The shadow is shaped and angled so that the point directs water onto the centre of the slate below.

RIDGE

The ridge is covered with cock’s comb, possibly original C17, ridge tiles. 

Traditional Farm Buildings in the South Hams: Their Adaptation and Re-use.

Environment and Development Service, South Hams District Council

Barn Guide 2004.pdf >

Although the rag slates forming the verge are nailed directly to the rafters, the laths are carried through underneath them so that the rags and the two or three courses of scantle slates are at the same level.

UPDATE JULY 2016

Boarding has been fixed to strengthen the structure and reslating is underway by 

jsroofing.co.uk

Images J S Roofing

Updated July 2016

Reslating is underway.

See the end of this page


Updated August 2017

New S Hams slating at Higher Uppacott

Recording the roof

Higher Uppacott Longhouse Laying a rag verge

Jordan Heritage Roofing

Higher Uppacott Longhouse

Laying a mounter eave

Jordan Heritage Roofing