by gap74 » Tue Mar 01, 2005 11:52 pm
Second up is the Historic Scotland report, the first of several structural reports but the only one not done by the owner's own structural engineers. This is comparitively optimistic compared to the proceeding reports, which point out that the costs and logistics of what this guy suggests may not be economically viable...
I should point out that the order I'm presenting this stuff in is the order it was sent to me, which seems to be roughly chronological.
240 BATH STREET GLASGOW, PREVIOUSLY ELGIN PLACE CHURCH
Date of Visit: 27 November 2004
Reporting Engineer: Lothian Webster [Historic Scotland]
Introduction
The former church on the North West corner of the junction of Pitt Street and Bath Street was discovered to be on fire around 5:45am on Friday 26th November 2004. The fire brigade were quickly on the scene and believed they had controlled and localised the fire to a room in the basement. However, it appears to have spread through the cavities in the walls and turned into a major conflagration. The fire was considered not to be fully extinguished even on the morning of the following day, Saturday 27th December 2004.
The local authority’s building control department and the fire department convened on site at 10:00 on Saturday 27th November 2004 to consider the condition of the building, inspection being made from hanging baskets and a walk round. The building could not be entered at ground level due to debris and the hazard from material falling from above.
Access beyond the “Herras” safety fencing defining the site was denied to Historic Scotland personnel during this exercise and only provided after 12:00am [sic?] when the fire brigade, building control and the owner’s structural engineer had completed their inspection. Historic Scotland’s engineer was given the opportunity to inspect from a hanging basket in the company of Glasgow’s building control engineer at approximately 13:30. It was advised at this time that the area around the building was to be made secure by relocating fencing to positions that would allow one way traffic down some adjacent streets. A dangerous building notice is to be served on the owner which will require making safe or demolition. Discussions will take place within the council on its approach to the structure during the week commencing 28th November 2004, these discussions will be of major import due to the inclusion of demolition in the notice. The position of the insurers and the extent and detail of cover is unknown.
This following report describes the building as observed from the limited inspection available and outlines an approach to making safe.
Description
The category A listed Structure was constructed in 1855 as a Greek Temple fronted church with basement. The main hall is rectangular with an extended portion to the rear incorporating a stair well and service rooms with lower level adjuncts for halls and offices to each side. The ashlar sandstone front and side walls are lamp blacked, the rear elevation is constructed in squared rubble. The front elevation consists a near full width ashlar stone staircase, with stone side parapets, leading up to a landing off which rise the six columns forming the hexastyle Greek Ionic portico. The entablature has a pediment which incorporates in the tympanum a sculpted floral decoration. The central portion of the wall incorporates three high doors and is recessed from the side stairwells walls.
The elevation facing onto Bath Street consists of five full bays with substantial height of solid stonework over, up to an overhanging wall head. The channelled stonework defining the basement below the main windows incorporates four bays and an entrance door adjacent to the lower level adjunct. The outer boundary of the site is formed in dwarf stone walls with a cast iron railings and a formed entry lintel over onto Pitt Street. The elevation facing onto and set well back from Sauchiehall Lane also has limited fenestration with five bays with channelled basement stone below.
The rear elevation is some 1.5 metres from the adjacent properties and has few window openings. There is a significant crack and bulge, neither of which is recent, in the lower levels of this wall to the towards Sauchiehall Lane where it is surmised there are few internal connecting walls. I am unsure about the existence of flues in this wall, I suspect there are none as chimney stacks exist elsewhere and pots are evident on the return walls above the lower levels adjuncts, none are evident on the rear wall head. The internal stairwell walls have been used to tie back this wall with patriss plates evident.
The roof is believed to have been a low duo pitch with lead over the wall head forming a hidden gutter behind raised edge stones. The support system was large timber trusses, subsequently strengthened by the addition of steel trusses, to each side with timber purlins running longitudinally likely supporting rafters and sarking.
Internally the hall appears to have had a mezzanine floor introduced, I am unsure whether galleries existed. As no actual measuring was possible at the time of inspection the dimension of the building are estimed from plans dated 2004, that may have been reduced, and assessment on site. The full length is approximately 32 metres front wall to rear and width 19 metres outer face of side wall to outer face of side wall. Outer walls appear to be full depth masonry with a width of around 750mm, wall head is approximately 1.2 metres wide giving an overhang of 450mm. The wall head stones are full width to counteract the cantilever effect of overhanging.
Condition
The roof condition was suspect over many years and this is reflected in the outer bow at wall head on the Bath Street elevation with some gaps in the coping stone joints. This is believed to be old movement which is reinforced by photographs of the building when first put up for sale. The roof structure was inspected by a government engineer in 1972 and it was noted at that time that measures to strengthen the roof had been carried out. Ends of trusses that had suffered rot had been removed and replaced with spliced metal end bearers. Other truss ends had been reinforced with metal plates and some trusses had been augmented by steel trusses placed either side and bolted through. In the cupola longitudinal latticed steel girders were introduced between timber beams and spanned onto introduced single steel trusses.
The roof structure as revealed by the fire induced loss of sarking and slates is much as described in the report of 1972. The heat of the fire has caused the light steel trusses to buckle and has severely charred the timber trusses and purlins. The trusses are still able to support their own weight however the cupola area looks precarious. The fact that the steel trusses have buckled as a result of expansion rather than push the wall head out reflects their structural purpose being to resist vertical loads, and demonstrates the wall’s solidity. Only one cap stone on the lane wall head was noted as having been displaced slightly outward. I understand there is an introduced mezzanine floor consisting of concrete “bison” slabs presumably on some steel support structure, this is now covered in roof debris. The remains of the roof structure will need to be removed utilising cranes and men in hanging baskets. Cross ties such as scaffold ladder beams or “Metsec” lattice beams to the wall heads will need to be introduced to compensate for the loss of the original trusses. It would be worthwhile at this stage to introduce a temporary roofing system such as “Coverspan” to allow the interior to dry out. To counteract the small risk of wall head stones being dislodged these should be strapped down.
Walls generally are sound with tight joints and no sign of major deflection, other than the commonly occurring slight bows caused by the roof truss deflections and old settlement and movement, there is little in the way of recent activity or major stone damage due to fire. The introduction of cross head wall ties as part of the roof structure removal should ensure the walls stability in the medium term; water shedding measure need to introduced to protect them against deterioration due to water ingress and weathering in the medium to long term. Window openings could not be inspected in detail but it appears that safe lintels are still intact. The windows can be framed out or lintels replaced should they have been compromised by the fire.
Removal of debris may need to be by crane grapple for large material and then hand removal out through existing doors and windows once overhead areas are secure.
The Greek Temple frontage has lost its roof and tie back to the main building, while it is likely the low profile, sturdiness of columns and general mass will be sufficient to ensure it stands the introduction of ties back to the front wall will be worth consideration.
An advantage the building has is that it is within a defined boundary and unless major wall collapse was to occur any localised failures will fall within the curtilage.
The rear wall has an historic movement problem that appears to relate to poor foundations and insufficient ties to the rear face of the wall. Localised shoring around the bulging area near the base off a thick raised concrete ground slab should secure the bulge against future outward movement in the short term.
Conclusion
I am of the opinion, subject to detailed close up inspection, that the outer envelope of the structure can be made safe and retained if appropriate shoring and tying is introduced. Any future use of the structure will likely include introduction of an independent supporting frame within this envelope.
Lothian Webster BSc Ceng MICE