Gensler Construction FAQ: Office-to-Residential Conversions, Tempered Glass, and the Costly Mistakes I Documented

Before we get to the questions: if you searched where to buy face paint and ended up here, this isn't that page. Wrong kind of paint. But if you're trying to figure out whether tempered glass belongs in a Gensler office-to-residential conversion, you're in the right place.

I've spent eight years managing construction-phase documentation for Gensler, mostly on office-to-residential conversions and interior fit-outs. I've personally made and documented 12 significant mistakes that added up to roughly $86,000 in wasted budget. Now I maintain our team's checklist so the next person doesn't have to repeat them.

Here are the questions I wish every client asked before we started.

1. What does Gensler construction actually mean?

Not what the search engine might suggest. Gensler construction isn't about pouring concrete or swinging hammers; Gensler is a global architecture and design firm. In my corner of the firm, Gensler construction means the construction-phase services we provide: documenting design decisions, reviewing submittals, answering RFIs, and making sure the design intent survives contact with a build site.

My experience is based on roughly 30 office-to-residential projects in North America. If you're doing a smaller conversion in Europe or Australia, your process and code requirements will be different. But the pitfalls I list here tend to travel well.

2. What is a Gensler office to residential conversion, really?

First, we ignore the pretty pictures and study the floor plate. Most office towers have deep floor plates and a core full of elevators; apartments need daylight and a way to get every sleeping room code-compliant. The March 2023 conversion changed how I think about this. We spent two weeks on a beautiful facade strategy before checking the column grid against a 60-unit residential layout. The geometry didn't work. We adapted, but it cost us time we could have used for something useful.

The process, basically: zoning and entitlement review, structural assessment, window and facade evaluation, MEP redesign, and then construction documents. If you're comparing options for Gensler office-to-residential conversion services, ask what happens before the renderings. The floor plate will make or break the project.

One thing I tell clients now: office cores are often bigger than residential cores. You might end up relocating elevators or shrinking corridors to fit units. That's a design and budget conversation you want to have early, not after you've fallen in love with a facade sketch.

3. Why does tempered glass keep coming up?

Because offices and apartments have different safety glazing rules. Tempered glass is heat-treated to about four or five times the strength of standard annealed glass, and when it breaks, it crumbles into small blunt granules instead of long shards. That's exactly what you want near a door, in a tub or shower, or in a window where someone could fall through it.

In a Gensler office-to-residential conversion, the issue is that existing office glazing is usually not made for residential occupancy. You can't just leave the low office window as-is. I still kick myself for a 2019 fit-out where I approved a glass schedule without checking a local amendment. We had to re-cut 14 panels. $8,900 in replacement glass plus a one-week delay. All because tempered appeared in the product title but the edge work didn't meet the code.

Also remember: tempered glass cannot be cut on site. It has to be cut and edge-worked before it goes through the tempering furnace. If your glazier says they can trim it to fit on the job, that's a red flag.

4. Is watch glass the same as tempered glass?

No. Watch glass usually refers to the thin curved cover on a wristwatch, or the little concave glass dish used in a chemistry lab. Neither belongs in a building envelope. I once saw watch glass in a spec because someone misheard channel glass on a conference call. It took three emails and a sample request before anyone realized the mistake.

If you're specifying architectural glazing, stick with tempered, laminated, or heat-strengthened glass. If you ever get a watch glass line item in a budget, ask for the manufacturer's cut sheet. That clears up the confusion fast.

To be clear, the glass on a typical watch face is not architectural tempered glass either. It might be mineral glass or sapphire. It's a different product category entirely.

5. Can we use regular glass to save money?

In some locations, yes. But I wouldn't bet a schedule on it.

Safety glazing rules in the U.S. generally kick in for doors, sidelites, and windows close to the floor. The exact threshold varies by state and code edition, so I won't recite numbers from memory. The pattern on two of my projects: an inspector catches the installed glass, the glazier says the spec allowed it, and the architect has the conversation no one wants.

The vendor failure in September 2022 changed how I think about this. A non-compliant glass order made it from the fabricator to the loading dock before our submittal review flagged it. That was a $7,400 mistake and an eleven-day delay. Since then, the checklist stops when the glazing schedule is signed. Not approved in principle. Signed.

An informed customer asks better questions and makes faster decisions. Print the code section. Give it to your glazier. Don't rely on a verbal, it's fine.

6. Wait, mailboxes? Seriously?

Seriously. This is the question nobody asks until the end, and it's exactly the kind of thing I document now.

If you're converting office space to apartments, you need a secure, centralized mailbox setup that satisfies USPS. Under federal law (18 U.S. Code § 1708), only USPS-authorized mail may be placed in residential mailboxes. The old office mailroom cabinet doesn't qualify in most cases. You need a USPS-approved bank of mail slots and parcel lockers.

According to USPS (usps.com), a standard letter measures 3.5 inches by 5 inches minimum and 6.125 inches by 11.5 inches maximum, with thickness up to 0.25 inches. If you design the mail slot with no room for a bubble mailer—and I did, in 2021—you'll be retrofitting lockers at $3,200 a set. Put it on the checklist.

There's something satisfying about walking through a converted building once it's occupied. After all the glass submittals and mailbox dimensions, seeing actual residents is the payoff. But only if the mailboxes are actually there on move-in day.

7. So where do I buy tempered glass for a conversion?

From a local glazing supplier, ideally one with residential construction experience. Ask for references, a written lead time, and a cut sheet that states the glass type, edge work, and any ceramic frit. The cheapest quote is rarely the final number. Honestly, I'm not sure why some fabricators bid glass replacement so low and then miss the schedule. My best guess: they underestimate how much glass goes to waste in quenching.

For U.S. projects, look for safety glazing certification that references ANSI Z97.1 and CPSC 16 CFR 1201. That's the standard that tells you the glass was tested, not just labeled. If a supplier can't show that documentation, keep looking.

And if you're still searching for where to buy face paint—this page won't help. But if you're scoping a Gensler office-to-residential conversion, now you know the three questions to ask first: floor plate, safety glazing, and mailboxes.