abqstudio Damp Exercise St John the Evangelist, Penge Sean Albuquerque - Year 1 February 2011 chartered architects and designers

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1 Damp Exercise St John the Evangelist, Penge Sean Albuquerque - Year 1 February 2011

2 Contents Introduction 1 Damp Generally 2 The Inspection 4 Conclusions 8 Drawings 9 Interior Photographs 12 Exterior Photographs 14

3 Introduction I have been asked by Mr David Hills, of The Architectural Association, to inspect St John the Evangelist Church at Penge, and to report on signs of damp within the building fabric, the suspected cause or causes of each incidence of damp, and any further investigation or remedial action required. 1

4 Damp Generally Damp be the result of a number of factors. Most simply put these are: Penetrating damp Condensation Service leaks Rising damp All buildings hold moisture in their fabric. What we refer to as damp is the result of excess moisture affecting the fabric of the building, both externally and - usually more importantly - internally. Penetrating damp can occur in many ways from damaged or defective roofing to defective rainwater goods causing damp to penetrate through walls. Heavy snowfall can,for instance, cause water to get into a building even with a well-detailed and otherwise properly functioning building envelope. More normally the reason damp will come to light is not an occasional incidence of damp penetration but a chronic one. 2

5 Condensation occurs in two ways: Surface condensation, were moisture vapour forms condensation on the internal surfaces of walls and windows; interstitial condensation, where inappropriately arranged layers of building fabric cause the formation of condensation within walls and roofs. Service leaks, from defective pipes or rainwater goods, often cause decorative damage to internal surfaces. It is also possible, though, that unchecked service leaks can lead to serious cases of damp both within and outside a building. Rising damp is much talked about, and equally much misunderstood. It is said that it can occur where moisture rises up walls my capillary action where there is a defective or non-existent damp proof course. More often than not, though, this is a case of penetrating damp where, for instance, external ground levels have progressively risen over years. 3

6 The Inspection The inspection was carried out on Friday 28 January 2011 at 2pm. The weather was overcast and cold (approx 4 ). There was no precipitation on the day of my visit or on the preceding couple of days This inspection of the building was visual only, and its scope was limited as there were certain areas we did not have access to. These were: The upper floor(s) of the tower The upper level offices in the North-East corner The South porch The roof Also, limited access was available to the floor void. You will find below a table setting out the location of each symptom of damp that was discovered, together with its suggested cause and any recommended action. The references and locations are shown on the accompanying ground floor plan. I have also included an appendix of photographs highlighting some of the incidences of damp discovered. The photographs are not an exhaustive record of all the defects discovered, merely an aid in understanding the context and appearance of some of the areas affected. 4

7 Ref Location Symptom Cause Action A 1 to 3 Severely flaking paint and blown/decayed plaster Blocked or inadequate rainwater goods. It appears that main valleys between nave and aisle roofs are served by only one rainwater pipe, secondary rainwater pipes (RWPs) having been blocked at construction of transepts. Either the RWPs were under-sized or they have become blocked and therefore overflowed. Water has penetrated through the solid masonry walls and resulted in spalling and blowing of plaster and decorative surface. It appears the rainwater goods have been repaired/replaced recently. Carry out calculations to confirm adequacy of existing RWPs and hoppers. It is important to have a regular maintenance regime to keep hoppers clear and RWPs fully functioning. Interior of church is well heated. After drying out (several months) cut out and replace areas of affected plaster and repair ready for redecoration. To provide a more long-term solution it may be advisable to examine the possibility of re-commissioning the disused internal RWPs at the western side of the transeptal arches in the arcade, though in the first instance a rigorous regime on monitoring and maintenance of the valley gutters above the north and south arcades, and RWPs 10 & 11, should suffice. B 1 Flaking paint and blown plaster at low level Unclear. Appears distinctly different from the cause of A. No sign here of rising damp. Suspect that this penetrating damp is connected with the part-octagonal feature outside at the junction of the tower and nave. Was this intended to be a stair tower, and has water made its way inside through failed joints in stonework? Repair and repoint stone externally. Carry out archive research to determine original function of octagonal feature. After drying out (several months) cut out and replace areas of affected plaster and repair ready for re-decoration. C 1 & 2 Numerous signs of water streaking on stonework of arcades. This is not visible on the surface of surrounding paint, and there is no apparent damage to plaster. Historic failure of valley gutter None. 5

8 Ref Location Symptom Cause Action D 1 Severe damp at high level. Cracked arch in wall below. Damaged/perished timber ceiling boards. E 1 Recently repaired damp patch on wall at springing point of ceiling. Damp penetrating through wall/roof. Missing tiles in roof above. Ill-fitting coping stones to parapet, with wide, open, mortar joints. Possible failure of leadwork either to valley gutter above or step flashing to intersecting parapet above. Repair roof and coping. Monitor crack in arch. Replace damaged plaster and timber lining boards and redecorate. Carry out immediate thorough visual inspection at roof level. F 1 Flaking paint. Dripping cold water storage (CWS) tank overflow. Failed ballcock? 2 Severe efflorescence on stone tracery of window. G 1 Damp on floor. Gap at edge of floor. No signs show on wall but likely damage to floor from urine/overflow of urinal and damp from regular cleaning. Source of failure in plumbing appears to have been repaired (very long, new, overflow pipe inserted through wall). Carry out visual inspection of CWS tank to confirm repairs effected. Allow affected area to dry and repair plaster/paint. Brush off efflorescence from stonework. Further examination of floor structure/deck to ascertain if repair is required. Replace vinyl/linoleum floor covering with integral upstand/skirting. H 1 Damp around edge of ceiling here it meets walls. Flat roof failure. Examine roof for recent repair. Depending on condition repair or re-roof immediately. Treat areas of un-blown plaster with stabilising solution and redecorate. J 1 Flaking paint on wall Undetermined Further investigation required. K 1 Severely flaking paint and blown/decayed plaster Failed leadwork of valley gutter or inadequate hopper/rwp. New rainwater goods appear to have been installed. Monitor situation and cut out/ replace area of affected plaster once dry. 6

9 Ref Location Symptom Cause Action L 1 Flaking paint at low level and near door. Penetrating (apparently rising) damp as a result of water collecting on paving immediately outside door. 2 Flaking paint at low level in corner. Suspected inadequate rainwater goods leading to penetrating damp through wall. M 1 Replaced floor boards. Anecdotal evidence of water ingress through roof. Closer inspection of paving required to determine if re-laying to fall away from building will remedy this problem. Closer inspection of rainwater goods at high level. Ensure gutter and RWP are correctly sized for roof area as they look small. Associated to this (but not directly) it would be advisable to install a third RWP at the Western end of this gutter run. None. N 1 Flaking paint at low level an in window reveal. Suspected failure of rainwater goods Rainwater goods appear to have been recently replaced. Monitor situation and cut out/replace area of affected plaster once dry. 7

10 Conclusions The majority of the areas identified above are the result of penetrating damp as the result of damaged, defective, or inadequately sized rainwater goods, or are the result of inadequately maintained or defecting valley gutters. It appears that some recent work has been carried out to rectify the problems, and before embarking on any costly replacement of rainwater goods I would suggest that a close eye is kept on the situation for the next couple of months. It would also be advisable to ensure that all of the gutters and rainwater pipes are adequately sized. This can be done by calculation and is something we can attend to in due course. I hope that you find this report useful and, importantly, comprehensible. Much of the solution to the damp problems in the church will depend on effective management and maintenance of the rainwater disposal system, so if there is anything contained within this document that is unclear please do ask. Once you have had an opportunity to digest its contents I think it would be helpful to meet and discuss how best to implement the recommendations that I have made. Sean Albuquerque ABQ Studio Ltd 17 February

11 Drawings 9

12 Future RWP RWP 10 A3 RWP 9 RWP 11 RWP 1 A1 B1 A2 RWP 2 C2 C1 RWP 3 N1 RWP 12 M1 RWP 13 RWP 4 L1 K2 D1 J1 K1 RWP 5 RWP 8 E1 F1 G1 H1 RWP 6 RWP 7 Floor Plan - Not to scale 10

13 Roof Plan - Not to scale 11

14 Interior Photographs 1 A1 A1 B1 A3 C1 D1 N1 12

15 Interior Photographs 2 E1 F1 F2 H1 H1 K1 L2 L1 13

16 Exterior Photographs 14

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