Triple glazing for the non-rectangular aperture. Shaped sealed units — arched-top windows, raked-top apex casements, circular portholes, elliptical bullseyes, Gothic-point ecclesiastical glazing, sliver and wedge cuts for gable apex insets — are cut to owner-supplied template or measured site survey. The 36mm triple-glazed build delivers full A-rated WER performance in geometries that standard stock units cannot serve. Most shaped-glazing demand sits in three buckets: heritage / period homes with original arched or Gothic-point sashes; modernist architectural casements where the apex of a gable or the curve of a cantilever is fully glazed; and conservatories / orangeries where roof-tile alignment forces non-rectangular side panels. This flagship handles all three via the same template-driven cut workflow. Technical specification (base 36mm triple build) Overall thickness 36mm Build-up 4mm clear / 12mm argon / 4mm clear with Planitherm Total+ soft-coat (face 3) / 12mm argon / 4mm clear Gas fill 90% argon (BS EN 1279-3) Spacer bar Warm-edge composite, black — twin spacers contoured to shape U-value (centre-pane) 0.8 W/m²K g-value 0.50 Light transmittance ~71% BFRC Window Energy Rating A or A+ (depending on frame, area, ratio) Standards BS EN 1279 (parts 1-6), BS EN 673, BS EN 410 Shape capability Arched-top, raked-top, circular, elliptical, Gothic-point, trapezoid, wedge, bespoke per template Shape categories we cut Arched-top (Roman arch, segmental arch, semi-circular) — period property top-light windows, Georgian and Victorian arched casements. Template: bottom dimensions + arch radius / springing height. Raked-top (sloped-top apex casement, gable inset) — modern architectural glazing on gable ends, dormer cheek casements. Template: 3-corner dimensions + apex angle. Circular and elliptical (bullseye, porthole, oval) — period villa portholes, contemporary feature glazing. Template: diameter (circle) or major/minor axes (ellipse). Gothic-point (lancet, pointed-arch) — ecclesiastical and church-conversion glazing, neo-Gothic period houses. Template: base width + apex height + point angle. Trapezoid and wedge cuts — gable apex slivers, stair-half-landing tall glazing, infill panels in skylight runs. Compound shapes (arch + base rectangle, arch + raked, bespoke) — fully bespoke per CAD or scanned template. Square or rectangular triple glazing is faster and cheaper — see the 36mm Standard Triple Glazed Unit for stock-size rectangular triple. For shaped doubles (less expensive, less thermal performance), see the double-glazing topical page. For shaped acoustic or safety triple, configure via the configurator after selecting the shape category. Template requirements For shaped triple, we need a template — either a physical cardboard / hardboard template at 1:1 scale, or a CAD file (DWG / DXF / SVG / PDF with measured dimensions), or photographs with reference measurements (tape measure visible at the four cardinal points). Templates are bonded to the cutting glass during production, so accuracy at template stage = accuracy at delivery stage. For circular and elliptical units, a measured radius / major-axis / minor-axis sometimes suffices without template, provided the aperture is true (not slightly squashed from frame movement). For all other shapes, send a template — the configurator includes upload paths for CAD and photo. Stock pricing — rectangular reference only The "stock sizes" below are notional reference points for cost expectation; the actual shaped unit price is per-shape per-template, quoted within 24 hours of template receipt. Use these as a comparison anchor: a shaped triple costs roughly 1.3-1.6× the equivalent-area rectangular triple, depending on cut complexity (arched: 1.3×; raked: 1.4×; circular: 1.5×; bespoke: 1.6×). Certification and standards Every shaped unit ships with: UKCA mark, BS EN 1279 Declaration of Performance, argon-fill certificate, shape-specific manufacturing record (template ID + cut tolerances ± 1.5mm), and BFRC WER calculation where the shape is large enough to register against the calculation methodology. For listed-building consents, we provide a heritage-glazing compatibility statement on request. Frequently asked questions How accurate are shaped cuts? Tolerance is ±1.5mm on linear dimensions, ±1.0° on angles, ±0.5mm on radius for circular and elliptical. Within those tolerances, the unit drops into a properly-templated rebate. The most common fitting failure is template error, not manufacturing error — get the template right and the cut is right. Lead time for shaped triple? 14-21 working days from template approval. Arched and raked add 4-7 days over rectangular triple; circular and elliptical add 7-10 days; compound shapes add 10-14 days. Template approval is sometimes a 2-3 day back-and-forth if measurements need refining — order earlier rather than later for project deadlines. Can I get shaped acoustic or safety triple? Yes — both are configurable via the configurator. Shaped acoustic triple (with PVB interlayer in the middle pane) is straightforward; shaped safety triple (toughened outer / laminated middle) needs the safety-glass stack to be cut, toughened, and assembled before lamination — adds 5-7 days lead time. Heritage / listed-building compatibility? For listed buildings, conservation officers typically permit shaped triple glazing where: (a) the sightline matches the original single-glazed unit; (b) the spacer bar is dark / recessed so it doesn't read as a modern cavity; (c) the unit is set inside the original rebate without external evidence of the modern build. We provide a heritage-glazing statement on request. For the slimmest heritage build, see the 12mm Histoglass-Equivalent Slim Conservation Unit — slim double glazing reads as single-glass-equivalent in most listed-building consents. What if my measurements are slightly wrong? Templates that arrive with measurement errors are flagged before cut — we send back a "measurement query" with annotated photos asking for the dimensions in question. Cut-with-error-as-supplied units are not warranted against fit issues. Sending a physical cardboard template is the safest measurement method for tricky shapes; CAD is faster but requires good source data. Will shaped triple fit in a 28mm-rebated frame? Not directly — the base build here is 36mm. For 28mm-rebate frames, configure via the configurator with the 28mm slim-rebate triple stack on a shaped template. The slim-rebate shaped triple is at the edge of manufacturing yield (thin panes + shape + dual cavity = more rejected units), so price is roughly 1.8-2.0× the rectangular slim-rebate triple. Warranty on shaped units? 10 years on edge-seal integrity (BS EN 1279-2). 10 years on argon retention to ≥80% of initial fill. 10 years on low-E coating performance. Transit damage covered 14 days from delivery — shaped units need particularly careful handling at install, so brief the fitter on receipt protocol before delivery date.
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