Chapel, Convent of Mercy, Thornhill, Culmore Road, Londonderry, BT48 8JF

A long simple hall church with its main axis orientated east/west and joined to the main house by a wide corridor porch with a small S.W. porch, partly stone built with low pitched copper roof. It is located at the southern side of Thornhill House. The east gable is plain without fenestration built in rock faced snecked sandstone with the quoins having a slight batter. The overhanging verge dressing is copper. The south elevation has an asymmetrical arrangement of windows. Each gable stonework is returned a short distance and the remainder of the nave wall rendered except for a battered stone pier defining the chancel end. A small S.W. porch with low pitched copper roof and stone gable projects from the rendered wall. The door is on the east side, recessed, and there is a 3 light stained glass tall window in the gable. Copper is dressed over the barges and fascia with concealed copper gutters and downpipes on each side. The chancel end is emphasised by 5 square headed lancets divided by mullions which continue from ground to underside of roof soffit. Beneath the low cill there are 5 stone panels. A continuous run of clearstorey windows divided by mullions goes from chancel to the SW porch with emphasised head and cill. Immediately over the porch roof there is a small narrow vertical square headed window. The welted copper roof is unadorned except for a small metal cross at west end mounted on a boss. The copper is dressed over verges and fascias and has a slightly greater overhang at gable apexes. Gutters and downpipes are in copper. There is a stone plinth at the base of the rendered wall. The west wall is similar to the east but with a large low pointed 5 light stained glass window with projecting mullions and surround all of which reach ground level. It has a low steeply weathered cill. Transoms are arranged on the 3 centre lights to form a cross defined by square panes. The north elevation is cement rendered with projecting flat roof sacristy block which stretches from the connecting porch and overlaps on the first light of the chancel windows. There are 5 chancel windows similar to the south side except that one is truncated. There is a matching run of clearstorey windows over the sacristy. The sacristy has a high stone plinth at the east. There is a ground level change. The sacristy is lit by groups of 4, 3 and 2 square proportioned windows. Roof is asphalted. The connecting porch from the convent has a wooden door on west side with a large square headed window on either side, unimposing, but was not the principal access to the chapel. The porch connection to the convent house is neatly done giving access to the main staircase. Gravel paths surround 2 sides of the chapel while at the west end there is a a sea of bitmac. The chapel occupies a prominent location at the south side with lawns sweeping away to south and east. It contrasts sharply with the architectural style of the house.