This procedure provides a method of control for construction of block masonry work in order to achieve compliance with the contract specifications and drawings.
.1 All precast concrete masonry blockwork will be carried out in accordance with the specification and Project Quality Plan.
In any circumstances where specifications are not provided or they are in any way incomplete, the matter shall be referred back to Consultant’s representative for additional information.
.2 Checks Prior to Start of blockwork:
i) Ensure that the area to receive the blockwork is as per the contract drawings and approved finishing schedule.
ii) Check if preceding activities have been inspected and approved.
iii) Ensure that blocks are procured from approved manufacturer (s). Except where otherwise approved in writing each material shall be obtained from a single source.
iv) Source certificates shall be obtained for all raw materials e.g. sand, cement and blocks to show compliance with the contract specification.
.3 Handling and Storage of Materials:
i) Blocks shall be delivered to site palletised, off loaded as near to the point of use as practicable on a clean hard surface free from contamination by mud or surface water.
ii) Cement shall be stored off the ground, kept dry and used in order of delivery.
iii) Store metal ties and straps under cover and protect them from damage and distortion.
.4 Preparation of Work, Materials and Components:
i) When the materials and components are distributed to the work area, ensure that the structure is not overloaded.
ii) Plan for scaffolding material required for block work at heights. Plan for additional manpower for lifting blocks at heights.
iii) Set out anticipating the position of openings etc. in the work above to avoid unnecessary cutting and adjustment of masonry units leading to incorrect or uneven bonding.
.5 Preparation of Mortar Mixes:
i) Mortar shall be mixed by machine except for small quantities only (not containing plasticiser). Hand mixing (if permitted) may be done on a watertight platform.
ii) When mixed at site, batch boxes shall be used to ensure correct and consistent mix proportions.
iii) Use mortars (other than retarded mortars) within 2 hours of mixing or as specified.
.6 Building Blocks Walls:
i) Build block work within permissible deviations as specified.
ii) Unless otherwise specified/permitted, lay blocks on a full bed of mortar and fill all joints. Keep courses levelled and perpend vertically aligned. Plumb quoins and all faces as the work proceeds. It is preferable to Align vertically every fifth or sixth perpend and `even out’ the size of Intermediate joints. Try to keep horizontal joints of uniform thickness.
iii) Do not carry one course more than the height specified in the contract specifications.
iv) Rake out joints as work proceeds, on all faces to be plastered or rendered. This will provide a good key for the coating.
v) If pointing is specified, the mortar used for the pointing should not be stronger than that used when constructing the wall unless specified otherwise.
vi) All blockwork shall be bonded to adjacent reinforced concrete structures by means of galvanised mild steel cramps at specified spacing unless specified otherwise.
vii) Partitions shall be bonded to main walls by toothing as specified in the contract.
.7 Chases and Holes:
Cut chases and holes neatly and without damaging the walls as per the following unless specified otherwise:
i) Chases in blockwork to be less than 75mm.
ii) For hollow units maintain a minimum of 15mm thickness between bottom of chase and void.
iii) Do not cut horizontal or raking chases to a depth exceeding one-third the thickness of the single leaf in walls or leaves contracted of solid units.
iv) Holes shall not exceed 300mm x 300mm unless specified otherwise.
v) Do not cut chases back-to-back exceeding the dimensional restrictions in (i),(ii) and (iii). Offset such chases in line by a distance at least equal to the wall thickness.
vi) It is preferable to use mechanical rotary cutters, particularly when it is necessary to avoid heavy impact and vibration. The number and position of chases shall be strictly in accordance with the specification since unauthorised chasing might adversely affect one or more of the functional requirements of the walls e.g. its loadbearing capacity.
.8 Appendix FINI/01/B shall be used to record deliveries of blocks if required by the specification.
PROJECT: PROJECT NAME SITE NO.:
CHECK SHEET FOR CONTROL OF BLOCKWORK
SECTION OF WORK ____________________________ LOCATION _________________
PRIOR TO BLOCK- WORK
1. Setting out (openings etc.)
SE/SU 2. Check source certificates of blocks, sand and
3. Check mix proportion of mortar.
GF CHECKS DURING BLOCKWORK
4. Check alignment/width of perpends.
5. Check line and level of courses.
6. Check metal ties.
7. Check raked out joints.
GF 8. Check toothing at joint of main wall with
9. Check compliance of chases with specifications.
APPROVAL TO PROCEED WITH THE NEXT TRADE
QA/QC – Quality Assurance/Quality Control, PE – Project Engineer, SE – Site Engineer,
SU – Surveyor, GF – General Foreman
SITE REGISTER (BLOCK)
PROJECT NAME: _________________________BUILDING PERMIT NO. _____________
AREA: ____________ PLOT NO.: _______________________BLOCK REQUIRED: _______________ SIZE: ______________
CONTRACTOR: ________________________CONSULTANT: __________________________________________
DATE OF PRODUCTION
Download Block work Method Statement in word format: CONTROL OF BLOCKWORK