1. PURPOSE
1.1 This specification defines the basic requirements for materials and workmanship for brickwork and blockwork.
2. SCOPE
2.1 This specification applies to all Air Products Europe (AP-E) sites.
3. RELATED DOCUMENTS
3.1 British Standards Institute (BSI) BSI PD 6697 Recommendations for the design of masonry structures to BS EN 1996-1-1 and BS EN 1996-2
4. MORTARS
4.1 The proportion of ingredients for mortar are defined by volume.
4.2 Unless otherwise specified, building mortar shall be of the following standard proportions: Work above D.P.C. level: 1 part Portland cement, 1 part lime, 6 parts sand – 1:1:6. Work below D.P.C. level: 1 part Portland cement to 3 parts sand – 1:3.
5. BRICKWORK AND BLOCKWORK
5.1 All brickwork and blockwork shall comply and be in strict accordance with all codes, standards, and regulations of the country in which the building works are to be executed.
5.2 All cavity walls shall be constructed in stretcher bond. Solid brick walls shall be constructed in Flemish bond, unless stated otherwise on the project drawings.
5.3 Cavity Walls
5.3.1 Cavity walls shall be constructed as shown on the drawings. Inner and outer skins shall be tied together with wall ties, built-in, and spaced at intervals for typical masonry units > 90 mm as follows: Vertically – not more than 450 mm Horizontally – not more than 900 mm
5.3.2 Cavity ties shall be staggered and evenly distributed. Near the sides of all openings, one additional tie shall be added for each 100 mm of opening height. No skin shall be more than 150 mm higher at any time than the other skin.
5.3.3 Additional Requirements Where the cavity work extends below the finished ground level, the cavity shall be filled with lean concrete to 75 mm below the finished ground level. Immediately above the finished ground level, every fourth vertical joint in the outer skin of external walls shall be left open sufficiently to form weep-holes. All mortar dropping shall be removed from all cavities. All joints and under sill cavities shall be brick/block closed. External skin shall be of facing variety brickwork. Unless otherwise shown on drawings, all internal wall skins shall be built with lightweight blockwork. When plastering is to be applied to the internal surface, keyed faced blocks shall be used. When plastering is not specified, smooth facing blocks suitable for painting shall be used.
5.4 Brick Reinforcement
5.4.1 Generally, mortar bed reinforcement shall be galvanised steel wire. The size and diameter shall be given on the project drawings. The reinforcement shall be lapped a minimum of 150 mm at all running laps, corners, and junctions or as per the manufacturer’s requirements.
5.5 Air Brick
5.5.1 Air bricks shall be insect-resistant mesh fitted.
5.6 Wall Restraints
5.6.1 Wall ties shall be metal hot dipped galvanised vertical twist type. Vertical twist pointing downwards.
5.6.2 Wall restraints shall be provided as shown on the project drawings. These shall be a proprietary type that can be installed as the wall is built. At movement joints the restraint shall have a debonded sleeve.
5.7 Damp-Proof Courses (D.P.C.)
5.7.1 Unless otherwise specified, damp-proof courses shall be a bituminous polymer type. Damp-proof courses shall be lapped 100 mm at joints and angles to form a continuous layer, which shall also be lapped with the Damp Proof Membrane if present. The DPC shall be bedded on a layer of cement mortar (1:3) having a smooth finish.
5.7.2 Cavity trays shall be provided above all openings, and weepholes shall be formed in the outer leaf just above the cavity tray. Minimum two weep holes per opening.
5.8 Below Damp-Proof Courses
5.8.1 All brickwork below D.P.C. level shall be sand lime and of specified quality (14 MN/m2).
5.9 Manholes and Pits
5.9.1 All below ground brickwork in manholes, pits, and chambers shall be constructed in engineering bricks (48.5 MN/m2) and a mortar of 1:3 (cement:sand).
5.10 Lintels
5.10.1 Lintels over openings shall be either prestressed concrete or proprietary cold formed metal. The size/capacity shall be given on the project drawings.
5.11 Cavity Wall Insulation
5.11.1 Cavity wall insulation where stated on the project drawings shall be the polyestryne board type of sufficient thickness and composition to achieve the required ‘U’ value. The insulation shall be fixed to the inner leaf in accordance with the manufacturer’s requirements.
5.11.2 A minimum 50 mm wide free air space shall be maintained between the insulation and the inside face of the external leaf.
5.12 Joints
5.12.1 Joints are required within the masonry walls to control movement due to expansion and contraction. The position and size of the joints shall be indicated on the project drawings and are dependent on the type of masonry unit. Clay masonry – unreinforced walls, max spacing 15m. Internal concrete blocks – unreinforced, max spacing between 6m to 9m.
5.12.2 The joints shall be sealed externally using a suitable polysulphide sealant with an appropriate compressible joint filler and backing strip.
6. SCAFFOLDING
6.1 Scaffolding shall be provided and overhead work will not be permitted without prior approval. Scaffolding fixing holes shall be made good with bricks and mortar to match surrounding work on both sides, as scaffolding is removed.
7. TOLERANCES
7.1 Walls shall be plumb true to line, level, and constructed to a tolerance of +5 mm for 5000 mm in any direction.
8. Quality
8.1 Testing of Bricks and Blocks
8.1.1 The engineer may take samples of any type of building, brick, or block, and submit these to an independent authority for testing. The engineer shall reject any consignment, or type of brick or block, should the result of such tests prove, in his opinion, to be unsatisfactory.
8.1.2 Samples of the bricks and blocks together with the necessary data sheets shall be submitted to the Air Products representative for acceptance. If the representative deems fit, the contractor shall construct a sample panel.
8.1.3 The contractor shall submit to the Air Products representative details regarding the proposed materials and products to be used in the construction – mortar mix, wall restraints, lintels, and the like.