New flagstone installation on a properly engineered granular base and lift-and-relay restoration of settled or heaved stone — Wiarton, Indiana, Pennsylvania and Eramosa.
Free On-Site Quote
Call or email directly for the fastest, most accurate quote — usually scheduled within 1 business day.
Problem & Risk Analysis
Flagstone failure in the GTA is almost always a base failure, not a stone failure. When polymeric sand washes out, joints open, and stones rock underfoot, the cause is an under-compacted granular base, missing edge restraint, or no drainage outlet — letting frost lift the stones a few millimetres every winter until the whole patio is unsafe.
Fadom Construction installs new flagstone over a properly engineered base — 150 mm of compacted Granular A over a geotextile separator, with 25 mm of high-performance bedding sand, edge restraint at every perimeter, and a positive drainage outlet away from the building envelope. Joints are finished in polymeric sand or, for mortar-set applications, a Type S mortar bed with full back-buttering.
Lift-and-relay scope covers settled, heaved and rocking stones on existing installations — we remove the stones, correct the base failure (added compaction, drainage repair, edge restraint replacement), and reset the original stones in the same pattern. Cracked individual stones are replaced from the same quarry to match colour and thickness.
Technical Service Breakdown
150 mm compacted Granular A over woven geotextile, 25 mm bedding sand, full perimeter edge restraint, and polymeric sand joints. Designed and graded for positive drainage 2% away from the building envelope so meltwater never sits at the foundation.
Where slip-resistant, fixed-joint flagstone is required (pool decks, formal landings), stones are full back-buttered and set into a Type S mortar bed over a reinforced 100 mm concrete slab — with a sealed grout joint and integrated drainage outlets to deck drains.
Settled or heaved stones are lifted intact, the failed base is excavated and rebuilt with correct compaction and drainage, and the original stones are reset in the same pattern. Cracked individual stones are replaced from the matching quarry — Wiarton, Indiana, Pennsylvania, or Eramosa.
Materials & Specifications
| Category | Material / Specification | Engineering Notes |
|---|---|---|
| Stone Variants | Wiarton (Ontario limestone), Indiana limestone, Pennsylvania bluestone, Eramosa | Selected by thickness, slip rating, freeze-thaw class |
| Thickness | Dry-laid: 50–75 mm. Mortar-set: 25–40 mm | Per CSA A23.1 freeze-thaw exposure F2 |
| Base | 150 mm compacted Granular A over geotextile + 25 mm bedding sand | Compacted in lifts to 98% SPMDD |
| Joints | Polymeric sand (dry-laid), Type S mortar with bond-break (mortar-set) | Polymeric re-activated per manufacturer water spec |
| Drainage | 2% positive grade, perimeter swale, deck drains for mortar-set | Outlet always away from building foundation |
Code Compliance
Flagstone in the GTA must be specified for CSA A23.1 freeze-thaw exposure class F2 — Wiarton limestone, Pennsylvania bluestone, and Indiana limestone all meet this rating at the thicknesses Fadom installs. With 40–55 freeze-thaw cycles per winter and accumulated snow-melt loading, the base specification (150 mm Granular A compacted to 98% SPMDD) is the single most important determinant of a 25-year service life. Pool deck installations are detailed to comply with the Ontario Building Code's pool barrier and slip-resistance provisions.
Service Area
Flagstone Repair & Installation installed across 10 cities across the Greater Toronto Area. Select your city for local pricing, lead times and recent installs.
Free on-site assessment, fixed-price quote, written workmanship warranty.
