As a building owner or owner’s representative, inspection of methods and materials on pour days are critical to ensure success and value for your money. Unscrupulous contractors may take advantage of a lack of inspection to cut corners; others may simply make mistakes. The only method to ensure that you get what you pay for is full-time inspection on pour days. Inspection also catches honest mistakes and minimizes potential human errors. It is critical that inspection company personnel are directed to communicate deficiencies on site immediately when they are observed, so that corrective action can be taken without delay to the project.
We recommend that a submission be made by your concrete flooring contractor stating the name and sources of all materials to be used on site prior to commencing work. This should be check against the specification, to verify on-site deliveries and for future reference.
We recommend that the following items be checked on every pour by a full time inspector:
- Granular base elevations (maximum +/- 10mm) – checked prior to the pour day and corrected.
- Ambient temperatures (ground, air and concrete)
- Air content of both air-entrained and non air-entrained concrete mixes (start of the pour and with cylinders)
- Concrete mix confirmation from delivery tickets
- Concrete batch times
- Initial concrete slump before plasticizer addition
- Plasticizer name and addition rate being used on site
- Final slump at point of deposit
- Spacing and diameter of rebar and dowels
- Manufacturers name, type and actual dosage rate of fibre reinforcing being used
- Weight of steel fibre per bag/box (weigh a bag to check accuracy)
- Steel fibre wash-out test (See CSA A23.2)
- Finished floor elevation
- Manufacturers name, type and actual application rate of surface hardener being used
- Type and quality of curing methods/materials
- Depth of sawcut contraction joints
- Manufacturers name, type and application rate of floor sealer being used
- Manufacturers name, type and depth of sawcut filler being used
- Cut test of sawcut filler depth
- Volume of concrete actually delivered versus theoretical usage
- On site unit weight and yield of concrete as delivered
- Floor tolerances (F-Numbers) measured within 72 hours of placement
- Slab thickness by coring (See CSA A23.1)
- Anything else that can avoid problems
Insist on pre-construction meetings to review submissions and specified methods and materials. These have proven to help avoid common problems in concrete construction.
Help to avoid problems, build quality and keep honest contractors in business by inspecting all work on pour days. If you have any questions, please feel free to e-mail us for assistance.