Granite Window Sill Price per Linear Meter: Three Meters, One Window
Granite window sill price per linear meter depends on which length the meter covers: the clear opening, the finished board, or the cut blank. On a straight window they differ by about ten percent; on a corner or bay window measured on the developed line, by more than twenty. Fix the basis first, then compare edge profiles, grooves and joints line by line.
What does 'per linear meter' actually measure on a granite window sill?
Three different things, and on a straight window they come out about ten percent apart; on a corner or bay window the gap runs past twenty. Opening width is the clear span of the masonry or concrete opening, which is what a buyer with a tape measure usually records. Finished board length adds the ears at both ends that embed into the wall and cover the plaster reveal. Cutting length adds a trim allowance at each end, where a skewed or chipped edge gets corrected. Take a 1.80 m opening, 60 mm ears and 20 mm trim per end (figures only to show the arithmetic): 1.80 m opening, 1.92 m finished, 1.96 m cut, so the longest runs 8.9 percent over the shortest. Before comparing two quotes, ask which of the three they mean.
| The 'meter' in the quote | What it measures | Who uses it | Relation to opening width |
|---|---|---|---|
| Clear opening meter | Clear size of the opening, ears excluded | Owners and designers, for budgeting | Reference point |
| Finished board meter | Opening plus ears at both ends | Factory order entry and scheduling | Two ears longer |
| Cutting meter | Finished length plus trim at both ends | Some factories, for material take-off | Two allowances longer |
Is the overhang past the wall face counted in the length or in the width?
In the width, not the length. A linear meter runs along the opening; the overhang runs perpendicular to the wall and changes the depth of the board. A 30 mm overhang means a 30 mm wider blank, which moves weight and yield but leaves the run along the wall untouched. One linear meter is width x 1 m: 300 mm gives 0.30 m² and 24.3 kg, 350 mm gives 0.35 m² and 28.4 kg, 17 percent more stone for the same meter at 81 kg/m² for a 30 mm board. So the question worth asking is not whether the overhang counts, but what board width the meter is priced at, because meters quoted at different widths are not comparable. A dropped front apron is separate: its length equals the board length and it is cut, dressed and polished along that whole run, so it is a per-meter fabrication item that neither adds to the width nor comes free with the rate. Settle the overhang together with the frame position and the insulation thickness; too much and the elevation reads as a heavy lip that is hard to terminate.
The opening is longer than one board. Where does the joint go, and is it charged separately?
It is charged separately, as its own line. There is no universal maximum length; three things set it: the long side of the blank available, the bed of the cutting machine, and the route the piece must travel through lift, stair turn and door. So do not ask how long the factory can make it; ask for the maximum single-piece length for the material you are ordering, then check that against your opening. Past that the sill must be jointed, and the joint belongs on a mullion or a sash division line where the frame hides it; at the centre of the opening every height difference shows. Both pieces should come from the same block and be book-matched, and a 30 mm sill benefits from a back stiffener at the joint. Jointing means edge cutting, matching and dressing, sometimes dowels, quoted per joint or per meter and never folded into standard edge polishing. A joint is also a sealant line and the weak point for later leakage, so use one piece whenever the length allows.
Why can't edge profiles and grooves be lumped into one line reading 'fabrication included'?
Because each one runs a different number of tool passes, and a single lumped line hands the choice to the supplier's default. A straight edge is one chamfer pass, the cheapest option. A single bullnose rounds the top arris with a profile wheel. Double bullnose and duckbill need several passes and the curved face still has to be polished evenly, and uneven polish shows under raking light. A drip groove is cut into the underside near the front edge to break water creeping back along the board; where it goes and how it is shaped is covered in our window sill drip groove article. A frame rebate is milled into the face so the frame sits into the sill and finishes flush, cut on the visible face where chipping is least forgiving, which makes it dearer than a groove. Put three things on the order: profile number or radius, groove position with width and depth, and factory fabrication. Itemised quotes can be compared; lumped ones deliver the cheapest default.
| Item | How it is made | How it is priced | What the quote must say |
|---|---|---|---|
| Straight chamfer | Squared, then one chamfer pass | Per meter | Chamfer size, inside the rate or separate |
| Single bullnose | Top arris rounded with a profile wheel | Per meter | Radius, shaping and polishing as one or two items |
| Double bullnose, duckbill | Several passes, curved face polished | Per meter | Passes per meter, polishing on the same face |
| Drip groove | Groove cut in the underside near the front edge | Per meter | Position, width, depth, made in the factory |
| Frame rebate | Rebate milled into the face for the frame | Per meter | Rebate size, tolerance to the frame |
On a corner or bay window, is the return at the corner measured once or twice?
Once, measured along the visible outer edge as one continuous line, not by measuring each side to the far outer corner and adding them; the corner is a point, so 1.80 m front plus 1.20 m return reads 3.00 m. The wrong way measures each leg to the far outer corner, which puts a 300 mm corner block into both legs and turns the same window into 2.10 + 1.50 = 3.60 m, a fifth more stone. The inner corner is removed material and is not deducted. Where two pieces mitre, each is measured to the centre of the joint, so the joint is neither double counted nor left out, and deducting the corner on the grounds that no stone sits there understates the notch. A bay window has three faces, front plus two returns, two corners counted once each, so the developed length exceeds the front width by two side depths. Keep the three faces from one block run or the interior will show three shades.
| Window type | How to measure | Common mistake |
|---|---|---|
| Straight window | Straight along the outer edge, end to end | Quoting the clear opening and dropping the ears |
| L-shape from one block | Outer edge as one continuous line, corner is a point (1.80 + 1.20 = 3.00 m) | Each leg measured to the far outer corner, 300 mm block counted twice (3.60 m) |
| Mitred corner, two pieces | Each measured to the joint centre line | Deducting the corner, understating the notch |
| Bay window, three faces | Front plus two returns, two corners once each | Measuring only the front width |
How do I tell in three minutes whether three quotes stand on the same basis?
Put five questions to each and see which ones go unanswered: is the meter the clear opening, the finished board length or the cutting length; what board width is the meter priced at and does the overhang fall inside it; are profiles and grooves itemised and which of them sit inside the rate; how many joints are needed past the single-piece limit and how each is charged; are corners and bays measured on the developed line or priced per piece. When all five are answered, the quotes sit on one line and what remains is material, finish and lead time. The sills we ship are mostly pale or red tones; Maple Red G562 is a core material for us, with quarry and processing on one site so blocks can be traced by batch. Where sills and surrounds are made together, profiles, joints and overhang must line up, and the surround page sets out the matching details.