A staircase or a balcony cannot be delivered in one piece, so it has to be assembled on your site by people working from a drawing. That is the risk. We take it out by bolting the whole thing together in our own Sheffield workshop first, standing it up exactly as it will stand at your property, checking it, photographing it, and only then taking it apart to go for galvanising or powder coating.
It costs us a day and a lot of floor space. We do it because the alternative is finding out on site, with a crane booked, scaffolding up and a customer watching, that something is 20mm out. At that point a 20mm problem has become a two week problem. Every photograph on this page is a real job from our workshop floor, and every one of them links through to the finished article.
What trial building actually means
A bespoke steel staircase or balcony is not one object. It is a set of fabricated parts, often made by different people on different days, that have to come together to within a few millimetres. Stringers, treads, landings, posts, balustrade frames, gates, glass clamps and fixing plates all have to line up with each other, and then line up with your building.
Trial building is the stage where we put all of those parts together in the workshop and prove it. Bolts go through. Treads sit level. Handrails meet. Posts land where the drawing says. If anything needs adjusting, it gets adjusted here, by the people who made it, with the machinery to do it.
The test for whether something gets trial built is simple: does it get built up, checked, and then taken apart again before it ships? Staircases and walk-out balconies do, because they are too big to travel assembled. Smaller units like our cellar doors, glass floor hatches and well covers do not, because they leave here complete and tested with nothing to prove on site. Building those is just building them.
Why it has to happen before galvanising
This is the part most people do not realise. Once steel has been hot dip galvanised, you cannot easily change it. Cutting or grinding a galvanised section destroys the coating at exactly the point you have just exposed, and a brushed or sprayed repair is never the same as the dipped finish. Welding to it is worse again.
So the sequence matters. Fabricate, trial build, correct, dismantle, then galvanise. Get that order wrong and every correction afterwards is a compromise. We would rather find the problem while the steel is still raw and still ours to alter.
Powder coating is no different. The whole thing is shotblasted and degreased before it goes through the oven, and once it is coated a grinder is the last thing you want near it. The same logic applies to glass. Glass is cut to suit the frame, and toughened glass cannot be cut, drilled or trimmed once it has been through the furnace. Proving the frame first is what stops a sheet of glass becoming scrap.
Six recent trial builds
Each of these shows a different reason the stage earns its keep, and each one links to the finished job.
Internal feature staircase with a kite winder
A flight, a landing and a kite winder tread, standing in raw steel with the balustrade frames offered up to check them. That is the staircase at the top of this page. Winders are where geometry gets unforgiving: the tread is tapered, the going has to be measured on the walking line rather than at the wide end, and the balustrade has to follow all of it. There is no sensible way to confirm that from a drawing alone. It goes up in the workshop, we walk it, and then it comes apart.
This one went to a house near Wakefield, where it replaced the builder's temporary timber flight in an opening that was already built and was not going to move for us. The finished stair, in black with Durbar chequer plate treads and welded mesh infills, is on the industrial staircase project page.
Galvanised access staircase on free standing posts
An access stair with open mesh grating treads and an intermediate landing carried on its own posts rather than fixed back to a wall. Trial building here is about the posts. Base plate positions, post heights and the landing connection all have to be right before the steel is dipped, because the first time anyone discovers a post is in the wrong place should not be when it is being held over a prepared base.
If you are weighing up whether your own stair needs posts, our galvanised steel access staircase and the rest of our external and galvanised staircases explain how the options work.
Walk out balcony frame with glass balustrade
A balcony frame laid out flat with its joists in, and the stainless posts and glass clamps set out along it. The glass had not been cut at this point, and that is the whole point. Post centres and clamp positions set the glass sizes, so proving the layout in steel is what makes the glass order safe.
That frame is now on the back of a house in Warwickshire. It went in as a replacement for a timber balcony that had come to the end of its life, which made the trial build worth more than usual: the wall, the door opening and the clearance under the sill were all fixed by the previous balcony, so there was no tolerance anywhere to absorb a mistake. More on these at walk-out balconies.
Glass floor balcony in modules
A larger assembly that ships in sections and is built up in sequence on site, with bar railings and a structural glass floor panel. Modules that fit individually do not necessarily fit together, and the order in which they go up matters. Standing the whole thing in the workshop is the only honest way to confirm both.
Spiral staircase under a circular wine cellar door
This one is worth explaining properly, because it is not what you might expect from a fabricator.
The customer needed a way down into a wine cellar, underneath one of our circular electric glass cellar doors. There were two honest answers to that.
One was a spiral we fabricate ourselves. Heavy steel, set out to BS 5395-2, guarding to BS 6180, UKCA marked to BS EN 1090-2, built to be walked every day for the next forty years. That is a substantial piece of steelwork and it is priced accordingly.
The other was an off the shelf kit spiral, which is what went in. It is a light, bolt together stair at a fraction of the cost, and we were straight with the customer about what that means. It is not a compliant staircase. The tread geometry, the gaps between the treads and the handrail arrangement do not meet what Approved Document K asks of a stair in normal daily use, and a kit stair of this type is not going to. For occasional access down to a wine cellar it is a perfectly sensible buy, and the customer chose it knowing exactly what it was and was not.
We will say the same thing to you. Where a spiral has to be compliant, has to carry a fire strategy, or is the only way in and out of a space, it needs to be fabricated and certified, and we will quote it that way. Where it is occasional access to a cellar or a store and you would rather put the money elsewhere, a kit stair is not a con and we are not going to pretend otherwise to sell you a bigger one.
What we did do was adapt it. It was cut and altered to come up correctly under the ceiling level, then trial built here against the cellar door opening to prove the two met properly.
That interface was the real risk on the job: a component we did not make, meeting a product we did. The full story, including what we will and will not certify on somebody else's product, is on the adapted kit spiral staircase project page, and the door itself is on the circular electric wine cellar door project page.
Custom steel bin store with a curved roof
Not everything we trial build is a staircase or a balcony. This is a heavy duty bin store for a contractor, standing in raw steel on the workshop floor with its curved panelled roof fitted, before it went out to be galvanised and then powder coated.
It meets the same test. It is too big to travel in one piece, it gets bolted together by somebody else on a site we have not seen, and once that frame is galvanised it cannot be altered. The curved roof is the part that makes it worth proving. Panels that follow a radius either sit down properly on the frame or they do not, and after the dip is the wrong time to find out.
Worth including because people assume trial building is something we reserve for the expensive jobs. It is not. It is what happens to anything that leaves here in pieces. If you want something one off made, that is our bespoke and made to measure work.
What it does not replace
Trial building proves that what we have made is right, and that it goes together. It does not prove that your wall, floor, opening or substrate will take it, and it is not a substitute for a site survey or for the judgement of your builder, designer, structural engineer or building control body. Those remain separate questions, and they remain theirs.
Where we have surveyed, we work to our own measurements. Where we have not, we work to the sizes we are given, and a trial build confirms the steelwork matches those sizes rather than confirming the sizes were right in the first place.
Ask to see yours
If we are making something for you, ask for the trial build photographs. We take them as a matter of course and we are happy to send them before anything leaves the workshop. Customers a long way from Sheffield tend to find it reassuring to see their staircase standing up before it arrives on a lorry.
You are also welcome to come and see it in person. We are at Arc Works, 150 Worksop Road, Sheffield, S9 3TN, and plenty of customers have stood on their own stairs here before they were ever installed. More on how we work on our bespoke and made to measure page, or get in touch.