Steel beam glossary

Common terms you will hear when planning a steel beam job, in plain English.

Adjustable steel prop

An adjustable steel prop is a telescopic steel tube with a pin and screw collar, used to support floors, walls and beams temporarily. Props are often called by a well-known brand name. Their positions and loads should be worked out properly for each job.

Asbestos refurbishment survey

An asbestos refurbishment survey identifies asbestos in the parts of a building that planned work will disturb. HSE says asbestos can be found in any building built before 2000, and its guidance says a refurbishment and demolition survey is needed before refurbishment work.

Base plate

A base plate is a flat steel plate welded to the foot of a steel column or post. It spreads the column's load and is bolted down to a concrete pad foundation or slab, holding the column firmly in position.

Bearing

The bearing is the part of a wall, column or padstone that the end of a beam rests on, and the support it gives. A good bearing is solid, level and strong enough to take the load the beam delivers at that point.

Bearing length

Bearing length is how far the end of a beam sits onto its support, measured along the beam. There is no single official minimum for every job: the structural engineer sets the bearing length in the design, and building control checks it on site.

Building notice

A building notice tells building control about work without submitting full plans for approval first. In England, work can start 2 days after one is given, with compliance checked on site. Northern Ireland allows building notices for some work to existing single dwellings.

Building warrant (Scotland)

A building warrant is the approval needed in Scotland for work to which the building regulations apply, including structural alterations, and it should be granted before work starts. Doing such work without one is an offence. Fees are set by law on the estimated value of the work.

CDM 2015

CDM 2015 is the Construction (Design and Management) Regulations 2015, the main law on managing health and safety in construction projects in Great Britain. For domestic clients, the client's duties pass to the contractor or principal contractor. Northern Ireland has equivalent 2016 regulations.

Certification of Design (Structure)

Certification of Design (Building Structure) is an optional Scottish scheme in which an approved engineer certifies a structural design. Verifiers must accept these certificates as complying with Section 1 of the building standards, and using one earns a discount on the warrant fee.

Completion certificate

A completion certificate is the document confirming building control is satisfied that finished work meets the building regulations. In England councils usually issue one within 8 weeks of completion. In Scotland a completion certificate is submitted to the verifier once the work is finished.

Deflection

Deflection is the amount a beam bends or sags under load. Every beam deflects a little, but too much can crack plaster, jam doors or strain glazing, so the engineer checks the chosen beam stays within suitable limits as well as being strong enough.

Dry pack

Dry pack is a stiff, low-water mortar rammed into the gap between a beam and its padstone, or under a base plate, so the steel bears evenly and tightly. Steel packing shims are often used alongside it to set the level first.

Fire-rated plasterboard

Fire-rated plasterboard is a denser board with additives that slow the passage of heat. Fixed around a steel beam in the layers its system specifies, it provides fire protection and a neat boxed finish ready for skimming.

Flitch beam

A flitch beam is a composite beam made from timber with a steel plate sandwiched and bolted between the timber pieces. It is sometimes used in loft conversions or older houses where timber suits the surrounding structure better than a steel section alone.

Full plans application

A full plans application submits drawings and calculations to building control for checking before work starts. In England a decision is due within 5 weeks, or 2 months by agreement. Full plans are mandatory in some cases, such as buildings covered by the Fire Safety Order.

Goalpost frame

A goalpost frame is two steel posts and a steel beam bolted together into a frame shaped like a football goal. It carries loads down to its own foundations, so it is used where existing walls cannot take beam ends or an opening is very wide.

Intumescent paint

Intumescent paint is a fire-protective coating for steel that swells into a thick insulating char when heated, slowing the rise in steel temperature. It lets beams stay on show, but must be applied at a specified thickness over a compatible primer.

Lintel

A lintel is a beam over a door, window or other opening that carries the wall above it. Lintels may be steel, concrete or, in older homes, timber. Wider openings or heavier loads usually call for a steel beam designed by an engineer instead.

Listed building consent

Listed building consent is permission needed to alter a listed building in ways that affect its character, including internal structural changes. It is separate from building regulations approval, and each UK nation has its own legislation. In Northern Ireland, breaching the requirement is an offence.

Load-bearing wall

A load-bearing wall carries weight from above, such as floor joists, a wall upstairs or part of the roof, down to the foundations. Removing one means providing new support, usually a steel beam, designed by an engineer and approved by building control.

Masonry support head

A masonry support head is a steel attachment fitted to the top of an adjustable prop, with a flat tongue that slots into a mortar joint. On suitable walls it lets a prop hold brickwork directly without cutting a hole for a needle.

Needle

A needle is a short beam, usually steel, passed through a hole in a wall above a planned opening and supported on a prop at each end. It holds up the masonry above while the wall below is taken out and the permanent beam is fitted.

Pad foundation

A pad foundation is a block of concrete in the ground beneath a column or post. It spreads the concentrated load from the column into the soil. The engineer sets its size and depth from the load and the ground conditions found on site.

Padstone

A padstone is a solid block, usually concrete or engineering brick, built into the wall under each end of a beam. It spreads the beam's concentrated load over a larger area of masonry so the wall below is not crushed. The engineer specifies its size.

Parallel flange channel

A parallel flange channel, or PFC, is a steel section shaped like a letter C, with a flat back and two parallel flanges. Engineers sometimes specify two channels bolted together, or use one where a flat face needs to sit against a wall.

Part A

Part A of the Building Regulations 2010 covers structure in England, and Wales publishes its own Approved Document A. It requires loads to be carried safely to the ground without deflection or ground movement that would impair the stability of another building.

Part B

Part B of the Building Regulations 2010 covers fire safety. Requirement B3(1) says a building's stability must be maintained for a reasonable period in a fire, which is why structural steel in homes usually needs fire protection. Wales publishes its own Approved Document B.

Party structure notice

A party structure notice is the formal notice given to a neighbour before work to a party wall under the Party Wall etc. Act 1996. It must be served at least two months before work starts, and lapses if work has not begun within 12 months and is not being pursued diligently.

Party wall

A party wall is a wall shared between two properties, such as the wall between terraced or semi-detached houses. In England and Wales, cutting into one to take the end of a beam is covered by the Party Wall etc. Act 1996.

Party wall award

A party wall award is the document party wall surveyors prepare when a neighbour dissents from a notice, or does not reply within 14 days. It records how and when the work may be carried out and commonly includes a schedule of condition.

Principal contractor

The principal contractor plans, manages and coordinates the construction work when more than one contractor is involved. On domestic jobs, CDM 2015 and the building regulations' dutyholder rules usually pass the client's duties to the principal contractor.

Principal designer

The principal designer plans, manages and coordinates design work when more than one contractor is involved. Under the building regulations' dutyholder rules, a domestic client's duties can pass to the principal designer instead of the principal contractor if they agree in writing.

Registered building control approver

A registered building control approver is a private building control business registered with the Building Safety Regulator. In England and Wales homeowners can use one instead of the council's building control service. Separate registers are kept for England and for Wales.

Regularisation

Regularisation is retrospective building regulations approval for work done without it. In England it covers unauthorised work done on or after 11 November 1985, only local authorities offer it, and the work may need opening up for inspection. Northern Ireland has regularisation certificates too.

RSJ

Short for rolled steel joist, RSJ is the everyday name for a steel beam that carries loads over an opening. Strictly it describes an older I-shaped section with tapered flanges, but the beam an engineer specifies for a home today is usually a universal beam.

S355 steel

S355 is a common grade of structural steel, where the number refers to its minimum yield strength in newtons per square millimetre. UK beam sections are commonly supplied in S355 grades, and the engineer's calculations state which grade is assumed.

Schedule of condition

A schedule of condition is a written and photographic record of a neighbouring property's condition, made before work starts. If cracks or damage are reported later, it shows what was already there. It often forms part of a party wall award.

Sole plate

A sole plate is a timber board or similar base placed under props to spread their load over the floor or ground. Without one, a heavily loaded prop could crush or punch through flooring, or sink into soft ground beneath it.

Span

The span is the distance a beam crosses between its supports. For a beam replacing a wall it is roughly the width of the opening. A longer span generally needs a deeper or heavier section, which the engineer works out from the loads involved.

Spine wall

A spine wall is an internal wall running down the middle of a house, commonly from front to back. It often supports the floor joists on both sides and sometimes parts of the roof, so it is treated as load-bearing until an engineer confirms otherwise.

Temporary works

Temporary works are the supports and protection put in place while permanent work is carried out, then removed. On a beam job they include props, needles, spreaders and sole plates. HSE expects them to be properly planned, with loads worked out.

Transfer beam

A transfer beam picks up a load from above, such as a wall or column, and carries it across to different supports below. They are typical where layouts change between floors, for example when shop units are opened up beneath flats.

UKCA marking

UKCA marking is the UK conformity marking for products placed on the market in Great Britain. Industry guidance says fabricated structural steelwork delivered to sites in Great Britain must be UKCA or CE marked against BS EN 1090-1, and CE marking remains available.

Universal beam

A universal beam, or UB, is a standard hot-rolled steel section shaped like a capital I, deeper than it is wide, with parallel flanges. It is efficient at spanning openings and is the section most often meant when people talk about fitting an RSJ.

Universal column

A universal column, or UC, is a standard steel section with an H shape, its flanges roughly as wide as the section is deep. That makes it good at carrying loads from above without buckling, so it is mainly used as a post or column.