Put in a 220 sq ft flagstone patio at the back of our East York home last summer. Chose Credit Valley limestone (Ontario-quarried) over bluestone and concrete pavers. Here is the full breakdown.
Why Credit Valley Limestone
Multiple reasons:
- Ontario stone - no cross-border import issues or supply uncertainty
- Warm golden/buff tones complement our red brick house
- Slightly more porous than bluestone = less slippery when wet
- Cost: $9/sq ft vs $16/sq ft for Pennsylvania bluestone
The Installation - Dry-Set Method
Our contractor (certified landscape contractor, CNLA member) insisted on dry-set rather than mortar over concrete. His explanation: in Ontario clay soil, frost movement is inevitable. Mortar joints crack. Dry-set allows micro-movements that relieve frost pressure.
Scope:
- Excavate to 10 inches below finished grade
- Remove clay soil (13 tons hauled away)
- 6 inches compacted granular A base
- 1.5 inch crusher dust bedding
- Flagstones set individually, hand-levelled with rubber mallet
- Joints: polymeric sand (Gator Bond EZ)
- Perimeter edging: armour stone border (4 pieces, decorative)
Cost
Excavation and removal: $1,800
Granular base: $1,200
Crusher dust: $380
Credit Valley limestone (240 sq ft with 10% overage): $2,160
Armour stone border (4 pieces): $680
Labour (2 person crew, 3 days): $3,600
Polymeric sand: $180
Total: $10,000 = $45.45/sq ft
One Winter Assessment
Zero movement, zero settling. All joints intact. The armour stone border has not shifted at all. The dry-set approach was clearly the right call for our clay-heavy soil.
Tip on Stone Variation
Credit Valley limestone has a lot of natural colour variation. Ask your supplier to pull from multiple layers/quarry cuts so you get natural variation. A patio that looks too uniform loses the natural stone character.