|Client:||Ramsay McMichael Chartered Building Surveyors & Redpath Bruce Property Managers|
|Approved Installer:||EBS Construction Ltd|
The corner area of a three storey tenement building was suffering from bowing of the elevations and masonry displacement. Dating from around 1900 and built from ashlar sandstone with random rubble-filled walls, the front and return elevations had limited lateral restraint and, with the close proximity of openings, concentrated load paths had resulted in structural problems.
Sympathetic repairs were needed that would stabilise the bowing wall, stitch cracked masonry, secure the internal and external leaves and create masonry beams that would reinforce the walls and spread the structural loads. All this had to be done while retaining the building’s aesthetic appearance.
In addition, the front eaves chimney head was taken down and rebuilt and dry rot was discovered, requiring extensive timber floor replacement and the fitting of a large steel bressumer beam across the bay window floor section. Fortunately, EBS Ltd were able to undertake this work as well as the Helifix repairs.
The Helifix repairs used a combination of their special purpose stainless steel products and concealed installation techniques. Cracked masonry on the bay windows was to be replaced and displaced masonry on the return elevation was to be reset where possible.
â— To provide lateral restraint in the bay areas and return gable elevation, 12 BowTie HDs x 1500mm were installed through the wall and into the floor joists before being bonded into the masonry.
â— To secure the return quoins to the front elevation and stitch a crack close to the corner, 14 fully grouted CemTies, 8mm x 1000mm, were installed.
â— A further 70 CemTies 8mm x 400mm were installed across the gable return to connect the external and internal masonry leaves, taking great care to avoid the chimney flues.
â— Some 40m of HeliBar was bonded into channelled-out mortar beds to stitch cracks and form deep masonry beams, using the existing sandstone, to reinforce the masonry and spread the structural loads.
Once the concealed repairs were completed the building was left visibly unaltered, which was an important requirement in this designated conservation area.