Why do two epoxy quotes for my Gloucester shop differ so much?

Two quotes for the same floor can be far apart even when both say "epoxy", because that word covers different systems, coats and prep methods.

Here is what is likely driving the gap in your Gloucester shop:

• System and product: ask each contractor to name the product and send its data sheet. Published 2025-2026 contractor ranges run from about $5 per square foot for lighter commercial systems to about $15 per square foot for commercial and industrial-grade work.
• Surface prep: Grinding to the right concrete surface profile takes time and equipment. One quote may include thorough mechanical prep; another may assume the floor is in better condition than it is. Standard prep, when priced separately, runs about $1 to $3 per square foot on published contractor pages, but some quotes bundle it in.
• Slab condition and repairs: crack filling, joint repair and levelling damaged areas are priced as separate work; ask whether each quote includes them.
• Moisture testing: One manufacturer's data sheet asks for a slab at or below about 75 to 80% relative humidity before coating. If one contractor includes in-situ probe testing (ASTM F2170) or calcium chloride testing (ASTM F1869) and a moisture-tolerant primer if needed, that adds cost the other quote may have skipped entirely.
• Coats and thickness: The data sheet sets the number of coats and the thickness for the system to perform as described. A quote that cuts a coat to save money is not quoting the same floor.
• Anti-slip texture, cove base and line marking: These are real costs that some quotes itemise and others omit.
• Closure and phasing: One manufacturer's data sheet lists foot traffic at 24 hours and heavy traffic at 7 days for a 100%-solids epoxy. If one contractor plans after-hours or phased work to keep your shop open, that affects price.

On the paperwork side, both contractors should provide a WSIB clearance certificate before work begins. Under WSIB policy 14-02-19, your shop, as the principal, is required to obtain that clearance and keep it in effect while work is underway. Ask each contractor for proof of liability insurance and references on similar commercial floors in the area.

To make sense of the two quotes, line up the product name and data sheet, the prep method and target surface profile, whether a moisture test is included and what happens if the slab fails it, the number of coats and thickness the data sheet calls for, cove base linear footage, anti-slip texture, and the closure window the contractor is committing to. One question worth putting to each contractor before you decide: if the moisture test comes back above the product's limit, what do you do next and what does it cost?