Frequently Asked Questions

Below are the questions we are asked most often by architects, main contractors, facilities managers and site teams. If your question is not covered here, please call us and we will answer it directly.

• Do I need Building Regulations approval for a mezzanine floor?

  Yes, and the approval needs to be in place before installation begins. Retrospective approval is not an option, and the consequences of proceeding without it can include an enforcement notice, invalidated insurance and difficulty when the property is sold or re-let.

  Approval comes from either Local Authority Building Control or a Registered Building Control Approver, and for a commercial mezzanine, a Full Plans submission is usually the sensible route. That involves submitting structural drawings and calculations for assessment, with approval typically granted within about five weeks.

• Who produces the structural calculations, and do I need to appoint my own engineer?

  For anything carrying a load, calculations are needed to demonstrate the structure is adequate for its intended use.

  We produce structural calculations as part of the design package, so there is no need to appoint a separate consultant for straightforward work. Calculations are issued in a form Building Control will accept.

  A mezzanine specified for light storage and one specified for pallet racking and an FLT are very different structures, and it is considerably cheaper to establish the loading before fabrication than after.

• What is UKCA marking, and does my project need it?

  UKCA marking applies to structural steelwork placed on the market in Great Britain. To supply it, a fabricator has to operate a certified Factory Production Control system to BS EN 1090-1, assessed by a notified body, and issue a declaration of performance with the steelwork.

  It applies to load bearing structural components: beams, columns, portal frames, structural connections and similar. Non-structural items such as a decorative gate or a security grille sit outside it. Where an item is somewhere in between, the test is whether it carries load as part of the building structure.

  Projects are also specified to an Execution Class, defined in BS EN 1090-2 and running from EXC1 to EXC4. The class is set by the consequence of failure and the type of loading, and it determines how rigorous the fabrication, welding and inspection requirements are.

• What height does a balustrade or handrail need to be?

  Heights are set by Approved Document K, and they vary with the situation instead of being a single figure.

  • External balconies, roof edges and floor edges: 1100mm minimum above finished floor level
  • Internal stairs and landings: 900mm minimum, measured vertically from the pitch line, which is the diagonal drawn across the front edges of the treads.
  • Barriers in front of an opening window: 800mm minimum.
  • Handrails on stairs: 900mm to 1000mm above the pitch line.

  Gaps are governed separately. No opening in a barrier should allow a 100mm sphere to pass through, which rules out widely spaced verticals and any horizontal arrangement a child could climb. A staircase with more than two risers needs a handrail; below 1m in width one side is sufficient, and wider flights need one on both sides.

• When do I need stainless steel instead of mild steel?

  Mild steel with an appropriate coating handles the majority of structural and architectural work, and it is significantly cheaper. Stainless earns its cost in specific conditions. The usual triggers are hygiene requirements, chemical exposure, frequent washdown, high humidity, or a setting where the finish itself is part of the specification.

  Food production, pharmaceutical facilities, laboratories, swimming pools and commercial kitchens are common examples.

  Where stainless is specified, grade matters as much as the material. Grade 304 covers most general applications. Grade 316 contains molybdenum and resists chlorides considerably better, which makes it the right choice for coastal locations, pool environments, de-icing salt exposure and many chemical processes.

• Do you need finished drawings, or can you work from a sketch?

  Either works. A good proportion of our enquiries arrive as a photograph, a hand sketch and a set of rough dimensions, and we take it from there.

  If you have architect's or engineer's drawings we will work to them and produce fabrication drawings for your approval before anything is cut. If you do not, we will carry out a site survey, take our own dimensions and produce the drawings ourselves.

  That survey stage matters more than people expect, because existing buildings are rarely square and rarely match the drawings held for them. Measuring on site removes the risk of a staircase arriving 15mm too wide for the opening.

  For anything structural we will want to know the loading, the fixing points available and the access route to the installation position before we finalise a design.

• What information do you need in order to quote accurately?

  The more of the following you can supply, the closer the quotation will be to the final figure:

  • Dimensions, or a sketch with approximate sizes
  • What the item has to carry or withstand
  • Where it will be installed, indoors or outdoors
  • Required finish, or the finish of existing metalwork it needs to match
  • Access to the installation position, including door widths, stair turns, lift dimensions and whether a crane or MEWP can reach
  • Any site specific requirements such as permits, induction, restricted working hours or shutdown windows
  • Your programme dates

  Access is the item most often left out and the one most likely to change a price. A fabricated staircase that has to be delivered in sections and welded together in a stairwell costs more than the same staircase craned into an open frame, and it is far better to identify that at quotation stage than on delivery day.

• Can you repair or modify existing metalwork instead of replacing it?

  Frequently, yes, and it is usually the cheaper route. Corroded sections of a fire escape can be cut out and replaced, a handrail can be extended, a stair balustrade can be brought up to current requirements without rebuilding the staircase, and a structural member can often be strengthened in place.

  Two things determine whether repair is viable. The first is the condition of the surrounding steel, which we would establish with a site inspection, because localised corrosion on the surface sometimes indicates more substantial section loss beneath it.

  The second is whether the existing item can be brought up to current standards. An older balustrade at 900mm on an external balcony will not satisfy current requirements regardless of its condition, and in a case like that replacement is the honest answer.

  Where we are matching into existing metalwork, we will match the section size, profile and finish so that the repaired area reads as part of the original installation.