Shot blasting noise in an Ottawa office tower, what to expect?

Shot blasting in an office tower is loud, dusty and disruptive, and the scheduling and containment decisions matter as much as the coating work itself.

What to Expect from the Noise and Dust

A shot blasting machine drives steel shot against the concrete at high speed and recovers it with a vacuum system. The machine itself produces significant impact noise, and the vacuum adds a continuous high-pitched tone. In a multi-tenant tower, that noise travels through the slab to the floors above and below, and through mechanical chases. Expect levels that make normal office conversation impossible in adjacent spaces. Dust containment on a shot blaster is better than open grinding because the machine is largely self-contained, but fine concrete dust still escapes at seams, doorways and penetrations if the contractor does not seal them before starting.

A few things shape how disruptive the work will be for your building:

• Floor area and condition: a larger pour or a heavily contaminated slab takes longer, extending the noise window.
• Slab thickness and construction type: a post-tensioned or composite deck transmits vibration differently than a solid pour; the contractor should know the slab type before starting.
• Occupied floors above and below: tenants on adjacent floors may need advance notice, and some leases or building rules set quiet hours.
• After-hours or phased work: evening and weekend shifts reduce tenant impact but the contractor should confirm the data sheet's temperature and ventilation requirements are met at those hours.

Under the Occupational Health and Safety Act and R.R.O. 1990, Reg. 851 (Industrial Establishments), the floor surface during and after prep must not present a hazard to workers on site. The contractor is responsible for dust and debris control while work is underway. If the slab has old resilient tile or black mastic, those materials may contain asbestos and must be tested before any grinding or blasting begins; removal of asbestos-containing material is governed by O. Reg. 278/05, which is separate from the floor coating work. Under OHSA s.30(1), the building owner must determine whether any designated substances are present and give prospective contractors a written list before a binding contract is signed.

For a building manager planning this work, a fair scope from the contractor should include: a written schedule showing which areas are blasted on which shifts, how the work zone is sealed from occupied spaces, what dust-collection equipment is used and how it is vented, the surface profile target (ICRI concrete surface profiles are the reference), and confirmation that the shot blasting result will be inspected before any primer goes down. Ask for the safety data sheet for every product being applied; Section 2 covers hazards and Section 9 covers flash point, which matters if any solvent-based primer follows the blast.

Before signing, ask the contractor how they plan to notify and protect tenants on the floors directly above and below the work zone during blasting hours.

You can submit your project details through the request form on this site, and contractors listed in the Ottawa Construction Network directory will reply by email.