Description of the contract
The WISE building was completed in 2010 and houses a combination of lecture rooms, office spaces and guest accommodation. Its experimental construction method utilises glulam timber frames embedded in 500mm thick hemp lime insulation finished with an external render coat. The timber beams are connected with galvanised steel plates and bolted. Terrace levels are constructed from 150mm thick timber cassettes supported by angle sections bolted to the beams and insulated with a layer of cork block insulation protected by a layer of plywood covered in an EPDM rubber roofing membrane. The building is topped with a series of flat roofs. These consist of a rubber EPDM covering over ply with Warmcell insulation beneath.
It has emerged that defects related to flashings, gutter outlets and trays have allowed water to penetrate parts of the structure causing areas of localised rot in timber beams, areas of ply and in the untreated timbers used to form cantilever edge details around main roofs and between the first and second floor accommodation.
The repair package for 2017 consists of:
South Gable Wall:
1) Repair to cracking and three inspection holes within the hemp lime.
2) Investigate and repair rot identified in the supporting beam in the terrace structure at the base of the wall linked to water penetration in the Garden Room Below. Water ingress is due to poor or missing flashing and also to possible faults in the installation of the EPDM roof covering, all of which should be exposed. This will also facilitate investigation related to the Garden Room Canopy works below.
3) Note: the first floor terrace provides a fire escape route from the first floor offices. A safe route out must be maintained throughout the works.
Garden Room Exterior Canopy
Investigation and repairs associated with the cantilever canopy extending along the ground floor of the West wall above the Garden Room. Rot suspected in the timber due to water ingress from the terrace above into the parapet wall due probably due to defective flashing details which should be replaced/improved.
Staircase Serving the First Floor Terrace on the South Elevation:
1) Currently the inner stringer of this stair is built into the wall and is suspected to be rotting in places. Rebuild stair with inner stringer mounted out of the wall leaving drainage gap and repair wall.
2) Note: This stair provides a fire escape route from the First Floor Terrace. Provision of an alternative route should be made for the duration of the works.
North West Parapet Wall Repairs
This wall runs behind the WISE restaurant extension and forms the edge of the 1st floor terrace. Test holes have revealed rot in the sill plate and vertical studs buried within the wall. The sill plate supports the end of the masonite rafters of the restaurant roof and the ends of these should be exposed and checked. The cause of the water ingress is associated with faulty flashings which should be replaced or improved.
Accommodation Walk way Repairs
1) Investigate and repair the water ingress and beam rot in the wall outside Room 1.03 and above between Room 2.02 and 2.03 near a gutter outlet As with the items below, the timbers around the affected areas must be considered suspect and therefore should be fully exposed and repaired as necessary.
2) Note: it is intended in a subsequent phase of repairs to replace the existing gutters formed in the roof perimeter with a external gutters outboard of the hemp lime walls.
3) Investigate and repair water ingress and beam rot on the North East corner outside Rooms 107/207. Again this is likely to be related to a gutter outlet.
4) Investigate and repair the cause of the damp staining between Rooms 2.10 and 2.11.
5) Replace boarding to fire escape landing near the south east corner.
6) As above to fire escape landing near the north east corner.
7) Note: Where ever possible, guest access to rooms must be maintained along with access to fire escape
Canopy Detail Repairs – 1st & 2nd Floors
1) Investigate and repair areas of damp and fungal growth which appears in the ledge detail between the first and second floors and at roof level on the west and south elevations.
2) Note: The flashing in these areas may be suspect and a modified form has been successful trialled at first floor level around the courtyard.
Metal roof repairs – first floor office
Investigate and repair damp staining and fungal growth around the ‘Wise Office’ extending from the West elevation at first floor level.
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