High level roof inspection. Condition & Options Study

Transcription

1 BROMPTON CEMETERY COnSERVATION PLAN: APPENDIX 3 High level roof inspection. Condition & Options Study The Royal Parks organised a Cherry Picker survey at Brompton Cemetery on 05th November 2014 to enable a visual inspection of the roofs of the Chapel, North Lodge, Colonnades and South Lodge. It was a cold, dry and sunny day. In attendance were: Catherine Cavanagh Sally Prothero Richard Davies Rachel James Robert Stevenson Russell Mundy (Part) Rik Fox (Part) The Royal Parks LDA MRDA MRDA The Friends of Brompton Cemetery Mundy Roofing Morton Partnership, Structural Engineers The lead dome to the Chapel is looking rather tired. As a minimum the gutters must be cleared of leaves and silt biannually. Splits in the lead are forming and repairs are required to the bottom half of the dome where the lead is dropping. Given the cost of access it is recommended that a programme of replacing the lead is considered. The roof is not leaking currently but it is coming to the end of its life. The roofs to the north lodge look in reasonable condition. A schedule of repairs will be prepared. Missing slates, of which there were a couple, should be replaced immediately. Moss build up should be cleaned off and there are areas of stone repairs and repointing required. The south lodge has a slate butterfly roof over the southern section. To the northern part there is a lead roof that is in good condition. Water ingress appears to be through the cracked parapets. The colonnade roofs were covered in Sarnafil within the last ten years or so. The south east colonnade roof was accessed. The roof covering is in good condition. A small tear was noted that should be repaired (under guarantee?) In conclusion the Chapel roof presents the most pressing priority. AUTHORS: MRDA REF: DATE: MRDA Architects & Conservation Consultants 2410_cherry picker survey 04th February 2015 rev B: PLANNING

2 was built in the early 1840s. It is Grade II* Listed. The lead roof dome was inspected from the cherry picker and the parapet gutter. The void between the inner and outer parts of the dome was accessed via the small hatch in the vertical up-stand on the west side of the dome. Water ingress: inside the chapel areas of water damage are visible. Paint has peeled and plaster spalled. These leaks are historic and not current. The pattern indicates that the water ingress was through the gutter (fig 2). Previous repairs: apart from the annual gutter clearance, Caroline McDonagh of TRP, reports that there has been no work on the dome roof in the last 8 to 9 years. Repairs are thought to have taken place in the 1990s, although the extent is unclear and in the late 1970s when the chapel roof was scaffolded and extensively repaired (fig 3). The parapet gutter: water was ponding in the gutters when we accessed the roof. This was due to silt build up around the outlets. The water drained away when the silt was cleared. If the gutters fill with water it will get under the lead and the timber substrate will rot - particularly as the steps in the gutter are less than would be specified today. If the gutter lining is replaced it should be re-engineered to provide higher stepsbetween bays. The gutters should be cleared bi-annually. The lead dome: the bottom half of the dome has been extensively repaired. The lead panels have dropped necessitating replacement of many edge clips and panel fixings. The top edge fixings are not visible, however if the lead has dropped they will probably be torn and the cover lap between the upper and lower panels insufficient. The lead repairs to the vertical up-stands at the bottom of the dome indicate the lead had cracked. Minor cracking was noted at the bottom of a couple of the lead rolls at the foot of the dome. The open joints of the lead rolls have been filled with mastic, not a recommended solution but which was presumably done to stem leaks. The mastic is compressible so the lead can move - the design life of the mastic is not known. An area of the lead at the bottom of the dome was rolled back, the boards underneath were dry, however the lead has become rather crystalline and is now becoming difficult to re-work / repair. The lead to the top half of the dome is in a more reasonable condition (fig 11) although a closer inspection may yield more defects. Inside the dome void: (figs 16 & 17) the space between the inner and outer dome is accessible by two small hatches on the E and W side. These are a tight fit, limiting access. The interior was dry and well ventilated and the dead birds and pigeon droppings were not extensive or recent. Evidence of former water ingress includes staining of timbers and some rotten supports, which appear to have been replaced. The roof-light: (figs 13,14 & 15) the single glazing curves in two direction. One pane is cracked. The roof-light has been repaired with tape / flash band which should be replaced. Lower roofs: (figs. 18, 19, 20) the roofs to the side wings have been replaced with standing seam aluminum roofing. Some cracking of lead flashings were noted. The roofs seem in satisfactory condition. Generally the lead to the dome is looking a bit baggy. The roof is not leaking at present but is coming to the end of its life. There are three possibilities: 1: Clear gutters bi-annually to ensure water does not pond in them. 2: Scaffold and repair the existing roof. To include the roof-light 3: Scaffold and replace the lead to the dome. Repair the rooflight. Given the costs of access scaffold (tbc) we recommend that the lead is replaced rather than repaired - an extensive scaffold will be required for both repairs and replacement and the lead appears to be coming to the end of its life. High level masonry repairs should be carried out at the same time. Listed Building consent will be required. A further inspection from a cherry picker is required to develop the proposed scope of work and specification. The cherry picker should be of a size to view in more detail the cupola and roof at the head of the dome.

3 fig.1 North elevation, as existing fig.2 Chapel interior; water damage (historic) fig.3 Chapel with scaffold. 1979

4 fig.4 Replacement patch fixings & clips. Repairs to rolls fig.5 Ponding in gutters fig.6 Split in mastic repair

5 fig.7 Lead has dropped at high level. fig.8 Replacement clips, mastic to free edge of lead rolls (full height) fig.9 New clips and patch fixings where lead sheet has dropped

6 fig.10 Crack to edge of lead roll fig.11 Top half of lead is in better condition fig.12 Replacement clips and repairs to bottom of dome

7 fig.13 Rooflight. fig.14 Flash band to glazing bars fig.15 Exposed wood to bottom of rooflight

8 fig.16 Interior of dome fig.17 Underside of rooflight

9 fig.18 East wing: standing seam roof fig.19 West wing: standing seam roof fig.20 North porch: lead roof

10 The North Lodge was built in It is Grade II* listed. The central section of the roof and the mono pitches to either side are accessible through the roof hatch. The roofs to the side wings are accessible only via a cherry picker or scaffold making access to clean gutters etc. difficult. Should roof hatches be added? The roofs to the north lodge look in reasonable condition. A schedule of repairs will be prepared. Missing slates, of which there were a couple, should be replaced immediately. Moss build up should be cleaned off and there are areas of stone repairs and repointing required. External access only Access possible via roof hatch External access only fig.21 North Lodge. South elevation fig.22 East wing. Low roof. Slipped slate rhs The North Lodge fig.23 Gatehouse. Central roof with access dormer

11 fig.24 Central Gatehouse, East wing. Low roof fig.25 Open joint in parapet fig.26 Delaminating stone The North Lodge

12 fig.27 North Lodge. West wing. Low roof fig.28 Damaged chimney pot, West wing fig.29 Moss build up The North Lodge

13 The South Lodge and Police box are unlisted. The South Lodge has an area of slated roof and an area of leaded roof (looks failry recent) with flet on the small rear extension. Ongoping leaks are reported and damp aptches are visible internally in the south part of the lodge and the toilet. The cvalley will leak when it fills up with leaves and water appears to be getting in via the cracked parapets. Neither of these roofs appeared to have been cleared for some time, judging by build up of debris and litter/clutter on roof of police box. The flowering ivy is invasive and needs cutting back, although not killed as it is good for insects. TRP to check that South Lodge and Police Box are included in gutter cleaning schedule. TRP to consider cutting back trees overhanging roofs and prune ivy over South Lodge fig.30 South Lodge. General view fig.31 South Lodge. Internal staining fig.33 South Lodge. Roofs fig.32 Police Box. General view The South Lodge & Police Box

14 fig.38 South Lodge. Parapet fig.34 South Lodge. Valley gutter fig.38 South Lodge. Open joints in parapet fig.35 South Lodge. Extension. Felt roof fig.36 Police Box The South Lodge & Police Box

15 the Central Colonnades date form They are Grade II* listed. The colonnade roofs were covered in Sarnafil within the last ten years or so. The south east colonnade roof was accessed from the cherry picker. The roof covering is in good condition. A small tear was noted that should be repaired (under guarantee?) Areas of stone repairs and cracked flaunching were noted. fig.39 Over view from Chapel roof fig.40 Over view from Chapel roof fig.41 Cracked cement flaunching fig.42 Split single ply membrane The Central Colonnades