Risers That Don't Rise and Other Acquisitions Regrets: Five Defects That Kill Deals
Photo: U.S. Army photo by Spc. Jordan Talbo, Public domain, via Wikimedia Commons
We have spent enough years crawling through ceiling voids and plant rooms ahead of acquisitions to develop a certain instinct. You learn to read a building the way a surveyor reads a schedule of dilapidations — and you learn which defects are nuisances and which are dealbreakers.
What follows is not a sales pitch. It is a list of the five defects that most often turn a promising commercial acquisition into a negotiation, a price reduction, or a walk-away. Every one of them has cost a client of ours money, and every one of them was findable before contracts were exchanged.
1. Ductwork That Was Never Designed to Be There
The single most common horror we encounter is post-completion ductwork modifications with no design intent behind them. Someone in 2009 wanted to serve a new tea point, so they tapped a spur off the supply duct, added a flexible connection, and never told anyone.
Why it's expensive: Undocumented modifications unbalance the entire ventilation system, often invalidate SFG20-aligned maintenance regimes, and can breach fire compartmentation if the duct passes through a protected wall without dampers. Rectification means re-commissioning the whole system, not just removing the spur.
The quick check: Ask for the original O&M manuals and commissioning certificates, then compare them against what is actually overhead. If the ductwork drawing shows one route and the ceiling void shows another, you have your answer.
2. Risers That Don't Actually Rise
We once surveyed a five-storey office where the so-called service riser terminated on the second floor. Above that, everything had been run exposed through occupied floors — a tangle of unlagged pipework and unarmoured cable strung along the corridor.
Why it's expensive: Without a continuous riser, future fit-outs require opening up every intervening floor. Landlord consents, out-of-hours working, and decanting tenants make even modest later works prohibitively costly.
The quick check: Physically walk the riser from plant room to top floor. Bring a torch. If doors are locked or 'inaccessible', that inaccessibility is itself a finding.
3. Asbestos Hiding in the Mechanical Services
Everyone knows to check the asbestos register for the obvious stuff. Fewer buyers look at the mechanical specifics: gaskets on flanged pipework, rope seals on boiler doors, insulating board around older plant, and — the classic — debris in ceiling voids from removed lagging.
Why it's expensive: Licensed removal of asbestos thermal insulation from plant rooms can run to five or six figures, and discovering it mid-refurbishment halts the programme entirely while surveys and removals are arranged.
The quick check: Cross-reference the refurbishment/demolition survey — not just the management survey — against any plant or pipework installed before 2000. If no R&D survey exists, commission one before exchange, not after.
4. A BMS That Is One Retirement Away From Collapse
We have opened plant room panels and found controls strategies running on obsolete controllers, with the only person who understands the programming having left the company in 2018. There are no graphics, no backups, and no as-installed drawings.
Why it's expensive: A full controls replacement on a mid-size commercial building routinely reaches six figures, and until it is done the building cannot be optimised, metered properly, or made compliant with tightening energy requirements.
The quick check: Ask who holds the programming knowledge, when the system was last backed up, and whether the head end is still supported by its manufacturer. Three questions, and the answers are usually revealing.
5. Plant at the End of Its Life, Priced as if It Isn't
Finally, the quiet one: chillers, AHUs and boilers that look presentable but are beyond their design life, with no capital replacement plan anywhere in the vendor's figures. The vendor's 'recently maintained' building may simply be an old building with a good maintenance contract.
Why it's expensive: Replacement, crane hire, temporary cooling or heating during changeover, and the awkward overlap with refrigerant phase-outs and efficiency legislation all land on the new owner's desk within the first few years of ownership.
The quick check: Get the age, manufacturer and model of every significant item of plant, and have a mechanical engineer assess remaining life. It is a day's work that routinely justifies itself many times over.
The Common Thread
Notice what all five have in common: none of them are visible in a marketing brochure, and all of them are discoverable with a competent pre-acquisition mechanical survey. The vendors are not always concealing anything — often the building has simply drifted from its documentation over two decades of small changes.
Our honest advice is unglamorous: spend a modest sum on survey time before exchange, and you will either negotiate the defects into the price or walk away from them entirely. Either outcome beats discovering them on day one of ownership, when every pound of remediation comes entirely out of your own pocket.
