Three things have to be found: the materials, someone to put them together, and a licensed engineer to review the set and seal it for your permit. None of them are exotic — but nobody in your town has built one of these before, so it helps to know exactly what you're asking each of them for.
It's tempting to price the glazing the day the drawings land. Resist it. Your engineer's review can change member sizes, rib spacing or pile count — and every one of those changes the quantities. Get quotes early to know the shape of the number, but place no order until the set has been reviewed and sealed.
Do this before anything else, because there is one question that can stop you cold — whether they will seal a design that isn't their own. Find that out while you still have every other option open.
Take the takeoff to two or three builders for preliminary numbers. They'll be bidding from a materials schedule, not from a photo, which is why the quotes come back comparable to each other.
Once the set is sealed and the permit is in hand, the quantities are final. The long-lead item is almost always the glazing, and the ribs if a shop is making them for you — start those first.
A Sophab looks unusual and is built from ordinary things. Exactly one component is made rather than bought — the curved ribs — and everything else is stock that a lumber yard, a glazing distributor and a pile installer already carry. What you hand a supplier is the materials schedule and takeoff from your plan set: quantities, sizes, grades and lengths, already worked out.
The foundation is screw piles driven below frost, not an excavation and a poured footing. This is a specialist trade with its own machine, and the installer almost always supplies the piles as part of the job. It is usually a half-day on site.
This is also the trade most likely to spot a problem early — buried services, ledge, or fill that won't take a pile where the drawing wants one.
The ribs are built up from standard dimension timber, laminated in layers over a form so they hold the arch profile. Every rib on your building is the same profile, which is the whole reason this is affordable: a shop sets up once and repeats.
If a shop tells you a curved glulam has to be pressed in a heated press, they are quoting you a different product. These are cold-laminated from stock lumber over a jig, which is a carpentry job.
The skin is twin-wall polycarbonate sheet, cold-bent over the ribs and sealed at the laps. It comes from greenhouse suppliers, sign and plastics distributors, and agricultural building suppliers — usually not from a window company.
Lead time is the reason this is called out. Sheet in your thickness and length is often not in local stock and comes on a truck from a regional warehouse. Ask for the lead time on your first call, not your last.
The rest is stock building material and you will recognise all of it.
We don't name suppliers, and that's deliberate — a distributor that serves us in New Brunswick is no use to you in Colorado. Everything above is described by specification precisely so you can search for it where you actually live.
Nobody local has built a Sophab. That sounds like a problem and mostly isn't: strip away the shape and the trades involved are piles, carpentry, a skin, and flashing a ledger — every one of them routine. What you are looking for is not somebody who has built an arch. It's somebody who reads drawings carefully and says "I don't know" out loud.
Give them the whole set, but point them at the materials schedule and takeoff. Quantities are already worked out, so what you get back is a labour and margin number rather than a guess — and three quotes built on one takeoff are actually comparable.
A pile installer for half a day. Carpenters for the bulk of it — base frame, ribs, purlins, end walls. Someone competent at flashing the ledger. An electrician if you want light and power. A floor, whenever you choose to do one.
"I'd sub the piles to someone." "I want the ribs delivered made up." "I've not bent polycarbonate — let me price a bit of extra time." All of that is a builder reading the job honestly. Instant confidence with no questions is the flag.
These sort the field faster than asking for references. The first three are about the job; the last three are about whether you want to be their customer.
Tie payments to milestones you can see — piles in, frame up, glazed, finished — not to dates on a calendar. And ask for a project of comparable complexity, not comparable shape. Asking for an arch they've built is asking for a reference that cannot exist.
We don't currently match you with a contractor. Regional matching is something we're building, and when it exists it will be a separate, optional add-on offered after a plan set — not a bundled promise, and not available everywhere on day one. Until then the guidance above is what we have, and it is genuinely enough: the trades are ordinary and the drawings do the explaining.
We produce an engineer-ready drawing set. A licensed engineer of your own choosing reviews it, satisfies themselves that it is right, takes professional responsibility for it, and seals it for your permit. That person is not us, and finding them is the step most people leave too late.
You want a professional engineer licensed in your own province or state, working in structural engineering. In Canada that's a P.Eng; in the United States, a PE.
Ask early, before you buy materials and ideally before you buy the set. An engineer who says no costs you a phone call now and a month later.
Ask this one first, in these words, because a meaningful share of engineers will say no and it is far better to hear it on the first call.
Both answers are legitimate professional practice. An engineer who seals a third-party design is taking on responsibility for someone else's arithmetic, and some firms simply won't. The ones who will are usually the ones who do a lot of residential and small-commercial review work — which is also why the building office's list is such a good place to start.
Send the whole package at once. The set is built to be checked rather than re-derived, and that is what keeps the review short.
What you are asking them to do: review the design, request whatever changes they need, take professional responsibility for it, and seal it. If they come back asking for a deeper section or another pile, that is the process working correctly — send it to us and we'll revise the set.
Their fee is theirs to quote. We don't set it, we don't collect it, and we won't print a figure for somebody else's professional services — it would vary by province, by firm and by year, and you would rightly hold us to it.
The thing that actually drives the number is how much they have to work out themselves. Every hour spent re-deriving a load path is an hour billed, which is precisely why the set arrives with the analysis, the reactions and the code references already in it.
We do not provide stamped or sealed plans. We produce an engineer-ready set; a licensed engineer of your choosing reviews it, takes responsibility for it and seals it for permit. That separation is deliberate and it protects you. Nothing on this page is engineering advice, a legal opinion, or a guarantee that any particular engineer, supplier or builder will take on your project.
The arch, drawn to your dimensions: plans, elevations, sections and connection details, the rib analysis for your local snow and wind, foundation reactions, a full-size rib template, a materials schedule and a takeoff. Revisions when your engineer asks for them.
The approval questions, the engineer, the contractor and the purchase orders. It is more phone calls than most people expect and less specialist knowledge than they fear — every call above has a script on this page.
If you would rather not run this alone, we'll walk it with you — the calls, the comparisons, and reading what you're told back into the design. Ask when you're ready. What we charge is set out in one place, and this consultation isn't an extra line on it.