Window Sills & Thresholds

Window sills and thresholds are the smallest pieces we cut and some of the most satisfying: a tired painted MDF sill swapped for honed marble changes a whole room's window; a granite threshold ends the annual repainting of a scuffed timber one for good. Because the pieces are small, most come from stocked offcuts and remnants at prices that surprise people.

We cut internal sills, external cills with weathering falls and drip grooves, door thresholds, saddle boards and radiator shelves in marble, granite, quartz and porcelain — polished, honed or flamed, with edges finished to match your room. Supply-only cut-to-size anywhere, templated and fitted across Surrey and South West London.

What are stone window sills cut from?

Internal sills are cut from the same 20mm materials as worktops — marble for period looks, quartz for colour-matched modern schemes, granite and porcelain for pure durability — with the front edge polished in your chosen profile and the ends finished where they show. Most sills fall well inside remnant sizes, so the material often comes from our offcut racks at a fraction of slab price.

Matching other stone in the room is the classic brief: sills cut from the same family as a worktop, vanity or hearth tie a scheme together for very little money. Send sizes and a photo of what you are matching and we will quote from stock.

Internal sill or external cill — what is the difference?

Internal sills are flat finished boards inside the glass — decorative, plant-bearing, wipe-clean. External cills do a weathering job: they need a fall of around 1:8 away from the frame, a drip groove on the underside so water releases clear of the wall, and frost-proof material — granite and porcelain are the honest choices, as marble weathers fast outside in British rain.

We machine falls and drip grooves on the CNC as standard on external work, and cut stooling flat spots at the ends where the cill builds into the reveal. If you are replacing crumbling concrete cills on a period house, flamed granite is the like-for-like that will not crumble again.

What about door thresholds and saddle boards?

Thresholds take more abuse per square centimetre than any surface in a house — every footstep, every suitcase, every dog. Granite and porcelain thresholds, honed or flamed for grip, are effectively permanent; marble saddle boards between rooms are the elegant interior version, bridging two floor finishes with a solid, bevelled strip.

We cut thresholds to width and length with bevelled or bullnosed arrises so there is no sharp trip edge, and to building-regs-friendly heights for level-access doorways where required. External thresholds get the same weathering falls as cills. Most are same-week remnant jobs.

What do stone sills and thresholds cost?

Guide prices: remnant-cut internal sills from £60–£150 each depending on size and material; made-to-measure sills from full slabs from £120; external granite cills from £140 per window with falls and drip grooves machined; thresholds and saddles from £70. Fitting is priced per visit, and several pieces fitted together always beats pieces fitted separately.

Supply-only is welcome — confirmed sizes in, finished pieces out, collection from West Molesey or delivery across Surrey and SW London. The usual promise applies even on small work: we beat any written like-for-like quote.

Can you match sills to my worktops or flooring?

Usually, yes. If we made your worktops, we may still hold offcuts of the exact material — worth asking even years later. Otherwise we match from current slab and remnant stock, which for popular quartzes and classic marbles gets imperceptibly close; for discontinued patterns we will show you the nearest honest candidates rather than promise an exact match.

The same applies to floors and hearths: bring a photo in daylight, or better a spare tile or offcut, and the matching conversation takes five minutes. Free samples travel the other way too.

How are stone sills fitted?

Internal sills bed onto the existing sill board or masonry with adhesive, packed level, with the junction to the wall caulked and the front edge left proud to your chosen overhang. Replacement means easing out the old MDF or timber sill first — a careful ten minutes with a bolster, patched and made good as part of the job.

External cills bed in mortar with the fall away from the frame, pointed to the brickwork, and sealed at the frame junction. Both are quick, tidy jobs: a whole house of sills is typically one day. For DIYers we happily supply-only with fitting guidance — the pieces are manageable and the adhesives forgiving.