Construction Glossary A-Z

AAC Blocks

Autoclaved Aerated Concrete blocks — lightweight, insulating masonry blocks cured under steam pressure. Faster to lay than clay brick and offer better thermal insulation.

Admixture

A chemical added to concrete or mortar during mixing to alter its properties — plasticizers improve workability, waterproofing admixtures reduce capillary absorption, retarders slow setting time.

Aggregate

The sand, gravel or crushed stone that makes up the bulk of concrete, bound together by cement paste. Coarse and fine aggregate gradation directly affects concrete strength and workability.

Anti-Skid Tile

Tile with a textured or rated surface (R10+) to resist slipping, specified for balconies, terraces and bathroom floors especially in Nepal's monsoon-prone climate.

Bamboo Scaffolding

Temporary work platforms built from lashed bamboo poles — still widely used across Nepal for cost reasons, though steel tube-and-clamp scaffolding is increasingly required above 3-4 storeys.

BIM (Building Information Modeling)

A digital 3D model of a building carrying architectural, structural and MEP data together, used for clash detection and coordination before construction begins.

Bitumen Membrane

An SBS-modified bituminous waterproofing sheet, torch-applied or self-adhesive, commonly used on flat terraces and roofs across Nepal.

BOQ (Bill of Quantities)

An itemized document listing every material, labor item and quantity needed for a project, used to get accurate quotes and control costs.

Brick Masonry

Load-bearing or infill walls built from fired clay bricks — Nepal's most common traditional wall material, now often used with confined-masonry seismic detailing.

Cantilever

A structural element (beam, balcony slab) that projects horizontally, supported at only one end — requires careful reinforcement design to resist bending at the fixed end.

Cement Grades (OPC/PPC/PSC)

Ordinary Portland Cement (higher early strength), Portland Pozzolana Cement (lower heat of hydration, most common for residential work) and Portland Slag Cement (best for sulphate-exposed foundations).

Confined Masonry

A construction technique where brick or block walls are confined by reinforced concrete tie columns and beams, widely used in Nepal for earthquake-resistant low-rise buildings.

Crystalline Waterproofing

A waterproofing method where an admixture or coating reacts with moisture in concrete to form insoluble crystals that seal capillary pores from within, common for water tanks.

Curing

Keeping fresh concrete moist and at a stable temperature for at least 7-14 days after pouring so it reaches its full design strength — skipping this is one of the most common site mistakes in Nepal.

Dado

A tiled or finished wainscoting section on a wall, typically 3-4 feet high in bathrooms and kitchens for splash protection.

DPC (Damp Proof Course)

A horizontal waterproof layer built into a wall near ground level to stop rising damp from moving up from the foundation into the structure above.

Ductility

A material's ability to deform (stretch) before it fractures — the property that makes Fe500D steel required in Nepal's seismic zones, since ductile structures absorb earthquake energy instead of failing suddenly.

Elevation

A scaled drawing showing one exterior face of a building, used alongside floor plans and sections in municipal permit submissions.

Epoxy Coating

A hard, chemical-resistant floor or bonding coating, used for industrial flooring and as a bonding agent between old and new concrete in repair work.

Expansion Joint

A gap built into a structure to allow for thermal movement without cracking — common in long facades, bridges and large concrete slabs.

FAR (Floor Area Ratio)

The ratio of a building's total floor area to the plot area, set by municipal building bylaws — determines how many storeys/how much built-up area a plot permits.

Fe500 / Fe500D

Grades of TMT reinforcement steel with 500 MPa yield strength. The 'D' (ductile) variant has higher elongation before failure, required in Nepal's seismic zones per NBC.

Fly Ash

A fine powder byproduct of coal combustion, used as a partial cement replacement in PPC cement and concrete — reduces cost and heat of hydration while improving long-term durability.

Footing

The enlarged base of a foundation that spreads a column or wall's load over a wider area of soil, sized based on the site's soil-bearing capacity.

Formwork (Shuttering)

Temporary molds — timber, plywood or steel — that hold wet concrete in shape until it cures enough to support itself.

Gabion Wall

A retaining wall built from wire-mesh cages filled with stone, commonly used on sloped or hillside plots across Nepal for slope stabilization.

Green Building

Construction that reduces environmental impact through material choice, energy efficiency and water conservation — increasingly certified and incentivized in Nepal's urban centers.

Grid/Cove Ceiling

A false ceiling system using a metal grid frame with gypsum or mineral fiber tiles, versus a fully plastered gypsum board ceiling — faster to install and access for repairs.

Grouting

Filling gaps between tiles, masonry joints or structural cracks with a cement or epoxy-based filler for stability and water resistance.

Hardcore

A compacted layer of broken stone or rubble laid beneath a floor slab or road as a stable, well-drained base before the concrete or finishing layer.

Hollow Block

A concrete masonry unit cast with internal voids, lighter than solid block and sometimes used for its own insulating air gap, common in partition walls.

HVAC

Heating, Ventilation and Air Conditioning — the mechanical systems that control a building's indoor temperature and air quality.

Insulation (Thermal/Acoustic)

Material — rockwool, glasswool, EPS, PUF — installed in walls, roofs or ceilings to reduce heat transfer or sound transmission.

IS Code

Indian Standard codes, widely referenced alongside Nepal's own NBC for structural design, material specifications and testing methods where NBC doesn't cover a topic directly.

Joist

A horizontal structural member supporting a floor or ceiling, spanning between beams or walls.

Kiln-Fired Brick

Clay brick hardened by firing in a kiln at high temperature, giving it strength and weather resistance versus sun-dried brick.

Lintel

A horizontal structural beam placed above a door or window opening to carry the load of the wall above across the gap.

Load-Bearing Wall

A wall that carries structural load from the floors/roof above down to the foundation, as opposed to a non-structural partition wall that can be removed without engineering review.

Louvre

An angled slat window or vent panel that allows airflow and light while blocking direct rain — common in Nepali kitchens, bathrooms and stairwells.

MEP

Mechanical, Electrical and Plumbing — the building services systems (HVAC, wiring, water/drainage) that are typically designed and coordinated separately from the structural frame.

Mortar

A workable paste of cement, sand and water used to bind masonry units together and for plastering — different mix ratios suit brickwork versus finish plaster.

NBC (National Building Code)

Nepal's set of mandatory building standards covering seismic design, materials and construction practices, referenced throughout municipal permit approval.

Net Metering

NEA's policy allowing rooftop solar owners to export excess power to the grid and offset their electricity bill, requiring an AEPC-listed installer for approval.

NRA

The National Reconstruction Authority — the Nepal government body overseeing post-earthquake reconstruction standards and approved housing designs.

OPC Cement

Ordinary Portland Cement — higher early strength than PPC, preferred for precast elements and RCC work needing faster formwork turnover.

Overhang

A roof or floor slab projection beyond the wall below it, used for rain protection and shading in Nepal's monsoon and strong-sun climate.

Parapet

A low protective wall built along the edge of a roof, terrace or balcony for safety.

Plinth

The raised base of a building between the foundation and the ground floor, protecting the structure from ground moisture and defining the building's ground-level height.

PUF Panel

Polyurethane Foam sandwich panel — an insulated prefab wall/roof panel with a foam core between two metal skins, used for fast-track warehouse and cold-storage construction.

Quantity Surveyor (QS)

A construction cost professional who prepares BOQs, verifies material take-offs, and manages contract cost administration on a project.

RCC (Reinforced Cement Concrete)

Concrete strengthened with embedded steel reinforcement bars, the standard structural system for multi-storey buildings across Nepal.

Rebar

Reinforcement bar (TMT steel) embedded in concrete to carry tensile loads that plain concrete alone cannot resist.

Retrofitting

Structural strengthening work added to an existing building to improve its earthquake resistance without full reconstruction — common across Nepal's post-2015 building stock.

RMC (Ready-Mix Concrete)

Concrete batched and mixed at a central plant to a certified mix design, then transported to site by transit mixer — used for large pours needing consistent grade strength.

Seismic Zone

A classification of earthquake risk for a geographic area used to determine required structural design parameters — all of Nepal falls in a high seismic risk zone under NBC.

Setback

The mandatory minimum distance a building must be set back from the plot boundary or road, defined by municipal bylaws and enforced at permit stage.

Slump Test

A quick on-site test measuring wet concrete's workability/consistency by how much a sample slumps after a cone mold is removed — used for quality control before pouring.

Soil Testing

Geotechnical investigation of a plot's soil-bearing capacity, done before foundation design to determine footing size and depth.

Terracing

Cutting a sloped plot into a series of level platforms — common site preparation for hillside plots across Nepal's hill and mountain regions.

Tie Beam

A horizontal reinforced concrete beam connecting columns at a set level (often plinth or lintel level) to tie the frame together, key to confined masonry seismic design.

TMT Steel

Thermo-Mechanically Treated reinforcement bars — steel with a hard outer layer and softer core, giving both strength and ductility for RCC structural work.

Truss

A triangulated framework of beams (timber or steel) used to span a roof structure, efficiently carrying load without a solid beam across the full width.

U-Value

A measure of how much heat passes through a building material or assembly — lower U-values mean better insulation performance.

Underpinning

Strengthening or extending an existing foundation deeper or wider, often needed when a neighboring excavation or an added storey increases load on the original footing.

Vapor Barrier

A material layer (often reflective foil or polyethylene sheet) that blocks moisture vapor from passing through a wall or roof assembly, paired with insulation in humid climates.

Vitrified Tile

A dense, low-water-absorption tile (under 0.5%) made by vitrifying clay and silica at high temperature — the standard choice for monsoon-prone Nepali floors.

Waterproofing Membrane

A continuous barrier layer — bituminous, PU liquid-applied, or sheet membrane — that stops water penetration through roofs, terraces, basements and wet areas.

WPC / PVC Door

Wood-Plastic Composite or fully synthetic PVC doors that resist moisture without swelling, used for bathrooms and exterior-facing openings where solid wood would degrade.

XPS (Extruded Polystyrene)

A closed-cell rigid foam insulation board with high compressive strength and zero water absorption, used for roof, foundation and cold-storage insulation where load-bearing capacity matters.

Yield Strength

The stress at which a material (like reinforcement steel) begins to deform permanently rather than springing back — the '500' in Fe500 refers to a 500 MPa yield strength.

Zoning Bylaws

Municipal regulations determining what can be built where — permitted building height, use type (residential/commercial), setbacks and FAR for a given zone or plot.