Structural Appraisal
As part of the feasibility study – a structural survey of the Powerhouse was carried out on 17th January 2006. The following represents a summary of our visual findings.
Limitations on the Survey
? The inspection was undertaken from ground and mezzanine floor level and excluded the basement areas which were partially flooded, full of debris and unlit and therefore considered unsafe for access.
? Parts of the structure which were covered, unexposed or inaccessible were not surveyed. It is not therefore possible to identify any defect which may subsequently become apparent arising from timber decay of any nature, beetle infestation, vermin, insects, defects in the constituents of concrete, the extents of bearings, tie or fixings or any such defects of a similar nature.
? The inspection did not include foundations. The conclusions regarding the condition of each structure have been drawn from the visual condition of accessible parts on the inspection date indicated.
General Description
The main building is approximately 37metres long by 24 metres wide and some 12.50 metres up to eaves level. Brickwork external walls to the main structure are generally approx 700mm thick with substantial internal piers at 4.5m centres
supporting steel roof trusses. The walls are a robust construction and appear to be plumb and generally in a stable condition. The building is completely open with the exception of a 3.1 metre high perimeter steel framed mezzanine floor to all sides except the south gable. The support steelwork to the pre-cast concrete floor is badly corroded and generally in a poor condition. It is assumed that this will not be retained as part of any proposed redevelopment.
Brickwork jointing externally is generally poor with extensive erosion and some defective/damaged brickwork. Re-pointing and replacement of damaged bricks will be required on all elevations. Signs of old settlement cracking on the north
gable wall – will require remedial measures. A large amount of old embedded steelwork should be removed and the walls made good locally. Extensive vegetation on all elevations needs to be removed - in particular the tree at eaves level on the east elevation. Brickwork internally appears to be in reasonable condition but will need cleaning and re-pointing generally. There are also signs of settlement cracking on internal face of the north gable wall.
The original overhead travelling crane is still in position beneath the roof trusses. Crane runway beams span between the main wall piers and appear in Page 14 The Powerhouse Feasibility Study Hyder Consulting (UK) Ltd 2212959 reasonable condition but will require cleaning and treatment to remove rust and reinstate protective coating. If the crane and rails are to be retained a closer inspection is recommended along with specialist advice on the possibility of restoration.
A basement structure approximately 3.70 metres deep appears to extend for the full foot-print of the building and from the limited inspection appears to contain extensive load-bearing masonry structures. The concrete slab is most likely a
ground bearing concrete slab on original ground. Water penetration into the basement is evidently a problem. If the basement is to be used in any redevelopment consideration will need to be given to installing a tanking system
to walls and floors. A full more detailed inspection of the basement is recommended to establish the full extent of the support structure and basement walls and floors.
The ground floor slab construction appears to be suspended across the full footprint of the building and supported off the basement structures. There are a number of framed penetrations in the slab and constructions seem to vary from
200mm thick steel joist /concrete infill to a steel joist/brick infill. Conditions and variable nature of the floor are generally poor. Replacement of the floor construction needs to be considered – dependent on the final proposed use of basement.
The roof structure comprises exposed steel trusses at 4.5 metres centres supporting steel beam purlins (7 rows to each roof pitch). Original slate tiled finish is supported on jack rafters lined with timber boarding. The steel trusses and purlins generally appear to be in reasonable condition but will require cleaning and treatment to remove rust and reinstate protective coating. Slate roof coverings are missing over a number of areas and timber rafters/ battens are
deteriorated and will need full replacement. A large, single storey out-building adjoins the east elevation of the main building, with finished concrete floor at a similar level to the basement. External brickwork walls are in a very poor Condition. The concrete flat roof was not easily accessed for a close inspection but in view of its age it must be assumed at this stage that extensive work will be required to upgrade and reinstate the waterproof coverings.
From information provided it appears all main walls extend down to basement level and are founded at rock head approx 4 metres below ground level. This will need to be confirmed in trial hole investigations when appropriate. It is assumed that the dilapidated steel structures to the south and north gables will be removed and not form part of any refurbishment.
Coal Authority records need to be consulted on historic mining beneath and in vicinity of the site. The presence of underground ducts have also been advised but locations and depths are unknown and further record information needs to be sought.
A culverted water course runs across the south gable but its exact route is not known. Further record information needs to be sought. Page 15 The Powerhouse Feasibility Study Hyder Consulting (UK) Ltd 2212959
There is no current information available on the existing drainage systems and further record information therefore needs to be sought. To create new mezzanine floor levels or similar structures within the main building all new support columns would need to extend through ground floor down to new foundation level at rock head beneath the current basement slab. All new structures should be independent of the existing building.