Table 1: Permissible Tolerances in Masonry Dimension Position in plan of any point Permissible tolerance ± 10 mm Length Up to and including 5 m ± 5 mm Over 5 m up to and including 30 m ± 10 mm Over 30 m ± 20 mm Height Up to and including 3 m ± 5 mm Over 3 m up to and including 6 m ± 15 mm Over 6 m ± 20 mm Straightness In any 5 m ± 5 mm Dimension over 5 m ± 10 mm Verticality In any 8 courses ± 5 mm In any 3 m ± 10 mm Masonry brick walls shall not deviate more than 20 mm from the vertical in their full height. The Contractor shall be responsible for the cost of all corrective measures required by the Engineer to rectify work which is not constructed within the tolerances set out above. The Contractor shall ensure that the stability of the building is maintained at all stages of construction, and provide temporary bracing as required. 2.2 Block Work 2.2.1 General Block work shall be laid in accordance with the recommendations of BS 5628: Part 3. Block work shall be set out and built to the respective dimensions, thicknesses and heights required and the Contractor shall set out courses, openings and the like with approved setting out rods. Blocks shall not be set in place within 28 days of casting. Blocks shall be wetted by sprinkling with fresh water before being laid. Blocks shall be laid in stretcher bond, solidly bedded, jointed and flushed up in mortar. Joints shall have a nominal thickness of 10 mm and extreme thicknesses of 5 mm and 15 mm. Vertical joints in face work shall be of even widths and plumbed at every fifth cross joint. Perpends, quoins and the like shall be kept strictly true and square and the whole properly bonded together and levelled. Blocks shall be well buttered with mortar before being laid and joints shall be thoroughly filled and flushed up from the top as the work proceeds. Page 8