{"product_id":"patio-bi-fold-door-triple-glazed-unit","title":"Patio \/ Bi-Fold Door Glass Unit (Triple Glazed, Oversize)","description":"\n\u003cp class=\"pr-flagship__lede\"\u003e\u003cstrong\u003eThe triple-glazed unit engineered for full-height door apertures\u003c\/strong\u003e. A 36mm triple-glazed sealed unit (4mm toughened \/ 12mm argon \/ 4mm clear with low-E \/ 12mm argon \/ 4mm toughened) sized for the patio and bi-fold door market — 1500mm to 2700mm wide, 2100mm tall — with both outer faces toughened to BS EN 12150 so the unit meets Approved Document N \"critical location\" requirements for door glazing as a side benefit.\u003c\/p\u003e\n\n\u003cp\u003ePatio and bi-fold doors are the most demanding application for sealed-unit glass in domestic construction. The apertures are huge (typically 2.1m tall, often 1.8-2.4m wide per leaf), the units must satisfy critical-location safety glazing, and thermal performance directly affects the EPC because doors of this size are often \u0026gt;20% of a room's external wall area. This flagship handles all three constraints in one stack.\u003c\/p\u003e\n\n\u003ch2\u003eWhy triple glazed for patio doors specifically\u003c\/h2\u003e\n\u003cp\u003eDoor glass faces a thermal punishment standard windows don't: every time the door opens, the entire glazed assembly is briefly exposed to outdoor conditions on both faces. That doesn't change the centre-pane U-value, but it does mean that any heat-loss penalty from sub-optimal glazing is paid much more often. For a south-facing patio door used 8-12 times daily, the difference between A-rated double (1.4 W\/m²K) and standard triple (0.8 W\/m²K) is meaningful over a heating season — typically 80-120 kWh\/yr per door across a UK climate.\u003c\/p\u003e\n\n\u003cp\u003eThe second reason is comfort. Floor-to-ceiling glass at A-rated-double thermals produces a noticeably cold zone in front of the door on still winter nights — radiant cooling against the body. Triple glazing's inner-face surface temperature stays close to room temperature, and the cold-zone effect disappears.\u003c\/p\u003e\n\n\u003ch2\u003eTechnical specification\u003c\/h2\u003e\n\u003ctable class=\"pr-spec-table\"\u003e\n  \u003ctr\u003e\n\u003cth\u003eOverall thickness\u003c\/th\u003e\n\u003ctd\u003e36mm\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003cth\u003eBuild-up\u003c\/th\u003e\n\u003ctd\u003e4mm toughened \/ 12mm argon \/ 4mm clear (Planitherm face 3) \/ 12mm argon \/ 4mm toughened\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003cth\u003eCavities\u003c\/th\u003e\n\u003ctd\u003e2 × 12mm argon-filled (BS EN 1279-3)\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003cth\u003eOuter + inner pane safety classification\u003c\/th\u003e\n\u003ctd\u003eBS EN 12150 + BS EN 12600 Class 1(C)1 (toughened)\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003cth\u003eU-value (centre-pane, low-E face 3)\u003c\/th\u003e\n\u003ctd\u003e0.8 W\/m²K\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003cth\u003eU-value (whole-door assembly, thermally-broken aluminium frame)\u003c\/th\u003e\n\u003ctd\u003e1.4-1.6 W\/m²K\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003cth\u003eg-value\u003c\/th\u003e\n\u003ctd\u003e0.55\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003cth\u003eLight transmittance\u003c\/th\u003e\n\u003ctd\u003e~71%\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003cth\u003eWeight\u003c\/th\u003e\n\u003ctd\u003e~30 kg\/m² — a 2400 × 2100 unit is ~150 kg, requires lifting jig\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003cth\u003eCritical-location compliance\u003c\/th\u003e\n\u003ctd\u003eApproved Document N — door glazing requires Class 1(C)1 below 1500mm. This unit satisfies that across the full pane.\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003cth\u003eStandards\u003c\/th\u003e\n\u003ctd\u003eBS EN 1279, BS EN 12150, BS EN 12600, BS EN 673 (U-value), Approved Document N, Approved Document L\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eWhere this unit is the right call\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBi-fold door replacement\u003c\/strong\u003e — original 4-pane and 6-pane bi-folds where the first-generation toughened double-glazed units have misted\/blown. Heritage frames and tracks can usually be retained; only the unit is replaced.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePatio (sliding) door reglazing\u003c\/strong\u003e — particularly aluminium and timber-aluminium composite systems where the 36mm rebate accepts triple. Older PVCu patio doors may need profile checks before specifying.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eGarden-room and orangery openings\u003c\/strong\u003e — full-height glazing onto landscaped gardens where comfort + thermal + safety all matter. Often pairs with the \u003ca href=\"\/products\/triple-glazed-safety-toughened-laminated-unit\"\u003eTriple Glazed Safety (Toughened + Laminated) flagship\u003c\/a\u003e for overhead-adjacent panels.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBedroom Juliet-balcony French doors\u003c\/strong\u003e at first-floor level — fall-from-height risk plus thermal-comfort considerations make triple-glazed safety the right spec.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHeat-pump retrofit projects\u003c\/strong\u003e with significant door glazing — the lower fabric heat loss directly improves ASHP coefficient-of-performance, particularly on shoulder-season cycling.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eFor French doors (single leaf, 600-900mm wide), see the \u003ca href=\"\/products\/french-door-glass-sealed-unit-symmetric-pane\"\u003e\u003cstrong\u003eFrench Door Glass Sealed Unit (Symmetric Pane) flagship\u003c\/strong\u003e\u003c\/a\u003e — sized for door apertures rather than full-height patio openings. For composite door inserts (small toughened-laminated panels in solid composite doors), see the \u003ca href=\"\/products\/composite-door-glass-insert-toughened-laminated\"\u003e\u003cstrong\u003eComposite Door Glass Insert flagship\u003c\/strong\u003e\u003c\/a\u003e.\u003c\/p\u003e\n\n\u003ch2\u003eStock sizes — patio\/bi-fold-specific\u003c\/h2\u003e\n\u003cp\u003eFive oversize stock sizes are below, all 2100mm tall to match the UK patio-door standard:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003e1500 × 2100 mm — single bi-fold leaf, narrow opening\u003c\/li\u003e\n  \u003cli\u003e1800 × 2100 mm — small bi-fold leaf, common 2-leaf splits\u003c\/li\u003e\n  \u003cli\u003e2100 × 2100 mm — square split aperture, 2-leaf bi-fold middle leaf\u003c\/li\u003e\n  \u003cli\u003e2400 × 2100 mm — typical sliding patio door leaf (3-track)\u003c\/li\u003e\n  \u003cli\u003e2700 × 2100 mm — large bi-fold\/slider, often the master leaf in 4-pane systems\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eDispatch 14-21 working days from order (toughening + triple-glazed assembly + oversize handling). Custom sizes — including taller-than-2.1m, shaped tops (raked apex roof glazing), and asymmetric bi-fold leaf splits — are priced via the \u003ca href=\"\/pages\/configure\"\u003e\u003cstrong\u003eonline glass configurator\u003c\/strong\u003e\u003c\/a\u003e.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eDelivery and handling:\u003c\/strong\u003e oversize units ship on bespoke timber A-frames via dedicated 2-person delivery service. Standard 5-7 day pallet networks cannot handle these units. A site survey for vehicle access (van width, gate clearance, pedestrian-route width) is included free with any order over 1.8m tall — contact the helpline before placing the order.\u003c\/p\u003e\n\n\u003ch2\u003eFrame compatibility — the critical specification step\u003c\/h2\u003e\n\u003cp\u003ePatio and bi-fold systems are highly system-specific. Major UK frame systems and their typical sealed-unit acceptance:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOrigin OB-72 \/ OW-80 aluminium bi-fold\u003c\/strong\u003e — accepts 28-36mm units, triple usually OK with bead change\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSmart Visofold \/ Visoglide\u003c\/strong\u003e — 28-32mm standard; some profiles take 36mm with deeper bead\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSchueco AWS \/ ASS series\u003c\/strong\u003e — designed for up to 50mm units, triple is straightforward\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOlder PVCu bi-fold systems\u003c\/strong\u003e — typically 24-28mm only; triple usually means full-frame replacement\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTimber bi-fold (e.g. JS Joinery, Heritage)\u003c\/strong\u003e — depth-on-rebate varies; site survey recommended\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eBefore ordering, send a frame profile photo and the existing unit edge thickness via \u003ca href=\"\/pages\/contact-us\"\u003eour contact form\u003c\/a\u003e for compatibility confirmation. The most common project blocker is the bead-rebate depth, not the sash size.\u003c\/p\u003e\n\n\u003ch2\u003eCertification and standards\u003c\/h2\u003e\n\u003cp\u003eEvery unit ships with: UKCA mark, BS EN 1279 Declaration of Performance, BS EN 12150 toughening stamp permanently etched on both outer and inner panes, BS EN 12600 Class 1(C)1 impact certificate, and an oversize-handling declaration covering the lifting plan. Heat-soak-tested toughening (BS EN 14179) is available as an order option — strongly recommended for large-span (\u0026gt;3m²) door units where nickel-sulphide spontaneous breakage risk warrants the additional process step.\u003c\/p\u003e\n\n\u003ch2\u003eFrequently asked questions\u003c\/h2\u003e\n\u003ch3\u003eIs triple glazing overkill for a door?\u003c\/h3\u003e\n\u003cp\u003eFor new-build and heat-pump retrofit: no — the comfort and EPC win is real. For straight reglazing of an existing A-rated-double bi-fold where the frame is tired: the payback is long (20+ years). The honest call is that triple delivers most of its value when the rest of the building fabric is being upgraded to match — otherwise the heat loss simply shifts to elsewhere in the envelope.\u003c\/p\u003e\n\n\u003ch3\u003eDoes the door still close properly with the heavier unit?\u003c\/h3\u003e\n\u003cp\u003eDepends on the system. Hinge load ratings are usually the limiting factor. A 2400 × 2100 triple unit at ~150 kg sits at or near the top of most bi-fold hinge specs — confirm the hinge model against the unit weight before ordering. For sliding patio systems, the running gear \/ track rollers are the equivalent constraint.\u003c\/p\u003e\n\n\u003ch3\u003eWill the unit fit my existing aluminium bi-fold frame?\u003c\/h3\u003e\n\u003cp\u003eModern thermally-broken aluminium bi-fold profiles (Origin, Smart Architectural Aluminium, Schueco, Reynaers) typically accept 28-36mm units. Older non-thermally-broken aluminium and most PVCu bi-folds are designed for 24-28mm only. Send a frame profile photo to \u003ca href=\"\/pages\/contact-us\"\u003eour contact form\u003c\/a\u003e for confirmation — this is the most common project blocker.\u003c\/p\u003e\n\n\u003ch3\u003eToughened both faces — is laminated middle worth specifying?\u003c\/h3\u003e\n\u003cp\u003eFor most domestic patio\/bi-fold doors, no. Floor-level glazing isn't classified as overhead under BS 5516, so the laminated fragment-retention requirement doesn't apply. For door panels above first-floor balcony level (fall-from-height risk), specify the \u003ca href=\"\/products\/triple-glazed-safety-toughened-laminated-unit\"\u003eTriple Glazed Safety (Toughened + Laminated)\u003c\/a\u003e upgrade.\u003c\/p\u003e\n\n\u003ch3\u003eAcoustic performance on a busy road?\u003c\/h3\u003e\n\u003cp\u003eThis unit's Rw is ~33-35 dB — modest, because the symmetric pane stack doesn't include acoustic-PVB damping. For door glazing facing busy roads, specify the asymmetric-acoustic variant in the configurator: 8.8mm acoustic-laminated outer + 4mm clear middle + 4mm toughened inner takes Rw to ~40 dB while preserving the Class 1(C)1 safety rating on the inner face.\u003c\/p\u003e\n\n\u003ch3\u003eWhat's the lead time?\u003c\/h3\u003e\n\u003cp\u003e14-21 working days for stock sizes (toughening + triple assembly + oversize handling). Custom (non-stock width or \u0026gt;2.1m tall) typically adds 5-7 working days. Heat-soak-tested toughening adds 3 working days. Shipping is by dedicated 2-person delivery on timber A-frame, not pallet network.\u003c\/p\u003e\n\n\u003ch3\u003eWarranty?\u003c\/h3\u003e\n\u003cp\u003e10 years on edge-seal integrity (BS EN 1279-2). 10 years on argon retention to ≥80% of initial fill. 5 years on the Planitherm coating. Toughened pane integrity is manufacturer-lifetime warranty against in-stock defect; spontaneous NiS-inclusion breakage is excluded unless heat-soak-testing is specified at order. Damage in transit is covered for 14 days from delivery — inspect on receipt and photograph before installer signs off.\u003c\/p\u003e\n","brand":"Pane Relief","offers":[{"title":"1500 × 2100 mm","offer_id":61853954376010,"sku":"TG-DRPTBF-1500x2100","price":462.0,"currency_code":"GBP","in_stock":true},{"title":"1800 × 2100 mm","offer_id":61853954408778,"sku":"TG-DRPTBF-1800x2100","price":555.0,"currency_code":"GBP","in_stock":true},{"title":"2100 × 2100 mm","offer_id":61853954441546,"sku":"TG-DRPTBF-2100x2100","price":647.0,"currency_code":"GBP","in_stock":true},{"title":"2400 × 2100 mm","offer_id":61853954474314,"sku":"TG-DRPTBF-2400x2100","price":739.0,"currency_code":"GBP","in_stock":true},{"title":"2700 × 2100 mm","offer_id":61853954507082,"sku":"TG-DRPTBF-2700x2100","price":832.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0895\/3515\/2458\/files\/triple-glazed-insulated-glass-unit-igu-cutaway_16c713ad-9a99-4c51-b206-68b5ba19cc05.webp?v=1779018553","url":"https:\/\/panerelief.co.uk\/products\/patio-bi-fold-door-triple-glazed-unit","provider":"Pane Relief","version":"1.0","type":"link"}