The fundamental flat glass product made by floating molten glass on liquid tin. Every tempered, laminated, and Low-E glass starts as float glass. We cut, install, and replace it for windows, tabletops, and custom projects across the DMV.
Float glass is standard flat glass -- the basic product that almost every other glass type is made from. When people say "a pane of glass," they usually mean float glass. It is called "float" glass because of how it is manufactured: molten glass is poured onto a bath of molten tin, where it literally floats and spreads into a perfectly flat, uniform sheet.
Before the float process was invented by Sir Alastair Pilkington in 1959, flat glass had to be laboriously ground and polished to achieve optical clarity. The float process eliminated this step entirely, making high-quality flat glass dramatically cheaper and enabling the glass-heavy architecture we see today.
Float glass in its basic form is also called "annealed" glass because it is slowly cooled (annealed) after forming to relieve internal stress. This makes it easy to cut, drill, and shape -- but it also means it breaks into large, sharp shards, which is why building codes require tempered or laminated glass in hazardous locations.
Every tempered glass pane, every laminated windshield, every Low-E coated window, and every insulated glass unit starts as float glass. It is the foundation of the entire glass industry. For non-safety-critical applications like picture frames, cabinet doors, shelving, and standard windows, float glass is the practical and economical choice.
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A continuous process that produces perfectly flat, optically clear glass sheets 24 hours a day, 7 days a week.
Silica sand, soda ash, limestone, and other raw materials are melted together at approximately 1,500 degrees Celsius in a gas-fired furnace. The batch melts into a homogeneous liquid glass over 24 hours.
The molten glass flows from the furnace onto a bath of molten tin at about 1,000 degrees Celsius. Glass is less dense than tin, so it floats on the surface and spreads into a perfectly flat sheet. Thickness is controlled by the speed of the glass across the tin.
The glass ribbon exits the tin bath at about 600 degrees Celsius and enters the annealing lehr -- a long oven where it cools gradually to room temperature over several hours. This slow cooling relieves internal stress, making the glass cuttable.
The continuous glass ribbon is automatically inspected for defects using laser scanners, then cut into standard stock sheets (typically 96 x 130 inches). These master sheets are then cut to order for specific applications.
The float process produces glass with excellent optical properties -- flat, distortion-free surfaces that transmit 83-87% of visible light without the grinding required by older manufacturing methods.
Float glass can be scored and snapped, drilled, beveled, polished, and shaped with standard glass tools. It is the only glass type that can be cut after manufacturing -- tempered glass cannot.
Serves as the base product for tempered, laminated, Low-E, tinted, frosted, mirrored, and insulated glass. Every specialty glass type starts as float glass.
The continuous float process produces uniform thickness with minimal variation. Modern float lines operate 24/7 and produce glass with fewer than 0.1 defects per square meter.
Available from 2mm to 25mm, covering every application from picture frames (2mm) to structural glass floors (25mm). Thicker glass provides greater strength and sound insulation.
For applications that do not require safety glass (tempered or laminated), float glass is the most cost-effective option. Standard window glass, tabletop covers, and shelving are common applications.
Single-pane window replacement in older homes, upper-story windows, and non-hazardous locations where building code permits annealed glass. We cut to exact dimensions on-site.
Protective glass tops for dining tables, desks, and coffee tables. Available in standard clear or low-iron ultra-clear. Edges can be flat-polished, beveled, or pencil-ground.
Custom-cut glass shelves for display cases, cabinets, and wall-mounted installations. Thickness is selected based on span and load -- we calculate the right thickness for your application.
Standard and oversized picture frame glass cut to exact dimensions. We offer regular clear, non-glare (etched), and museum-quality UV-protective options.
Replacement glass for kitchen cabinets, china cabinets, and display furniture. Available in clear, frosted, textured, and seeded patterns.
Float glass cut to any shape for custom projects -- mirrors, signage backing, greenhouse panels, and specialty installations. We handle circles, arches, and complex shapes.
Float glass (annealed glass) is standard glass that has been slowly cooled after forming. It breaks into large, sharp shards. Tempered glass is float glass that has been reheated and rapidly cooled (quenched) to create internal stress that makes it 4x stronger. When tempered glass breaks, it shatters into small, blunt pebbles. Building codes require tempered glass in hazardous locations like doors, low windows, and shower enclosures.
The green tint in standard float glass comes from iron oxide (Fe2O3) naturally present in the silica sand used to make glass. The tint is most visible when looking at the edge of the glass or through thick pieces. Low-iron glass (also called ultra-clear glass) uses specially purified sand with reduced iron content, eliminating the green tint and increasing light transmission from about 83% to 91%.
Yes. Float glass can be scored and snapped to virtually any rectangular or straight-line shape. Curved cuts are also possible with specialized equipment. This is a major advantage of float glass -- it can be cut on-site or in our shop to exact dimensions. Once glass is tempered, it cannot be cut or drilled without shattering. This is why all cutting, drilling, and edging must be done while the glass is still in its annealed (float) state.
Float glass is safe for many window applications, but building codes restrict its use in certain locations. It is not permitted in doors, sidelights next to doors, windows within 18 inches of the floor, wet areas (bathrooms), and near stairs or ramps. These locations require tempered or laminated safety glass. For standard windows above 18 inches from the floor and away from doors, float glass is code-compliant and commonly used.
Float glass is manufactured in thicknesses from 2mm (about 1/16 inch) to 25mm (about 1 inch). The most common thicknesses for residential windows are 3mm (single-strength, about 1/8 inch) and 6mm (double-strength, about 1/4 inch). Thicker glass (10mm, 12mm, 19mm) is used for tabletops, shelving, and commercial applications. We stock the most common sizes and can order any thickness for custom projects.
Float glass replaced plate glass in the 1950s-1960s. Plate glass was made by pouring molten glass onto a flat surface and then grinding and polishing both sides to achieve optical clarity -- an expensive process. The float glass process, invented by Pilkington in 1959, floats molten glass on a bath of molten tin, producing perfectly flat, optically clear glass without grinding. Today, virtually all flat glass is float glass.
Heat-treated float glass -- 4x stronger, safety-rated
Two float glass layers bonded with PVB interlayer
Ultra-clear float glass without the green tint
Color-infused float glass for glare and heat control
Float glass with metallic coating for energy savings
Float glass with acid-etched or sandblasted surface
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Heat-treated float glass -- 4x stronger, safety-rated
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Learn moreWindow replacements, tabletop glass, shelving, or custom cuts -- we provide free estimates for all float glass projects across DC, Maryland, and Northern Virginia.
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