18,000 homes “lost” because of the second staircase rule? Here’s the real maths — and what investors in the North should do next
18,000 homes “lost” because of the second staircase rule? Here’s the real maths — and what investors in the North should do next
Another safety tweak… or a housing handbrake?
Place Base claims the government’s second staircase rule at 18m is effectively wiping out almost 18,000 homes a year from the development pipeline.
Ministers call it scaremongering and repeat the same slogan:
“1.5 million homes without compromising safety.”
And while Westminster argues, the real world is doing what it always does:
architects are redrawing cores
cost plans are getting uglier
lenders are asking harder questions
and developers are quietly killing marginal schemes
If you’re developing or backing resi in Sheffield (or anywhere in the North), this isn’t political theatre.
This is viability risk, yield compression, and delivery delays hitting your ROI.
And here’s the uncomfortable truth:
Both sides are right — and both sides are lying by omission.
What the rule actually says (no fluff)
Since 2023, new residential buildings above 18m in England require:
✅ a second protected staircase
Place Base says that requirement “removes”:
~17,960 homes per year
~90,000 homes over five years
They argue the threshold should be lifted to 50m, pointing out other countries have higher limits.
Government response?
“No.”
They claim strong expert consensus that second stairs improve evacuation and firefighter access.
And yes — they do.
But the question isn’t whether they help.
The question is:
Is the cost-to-safety benefit worth the damage it does to supply, especially in lower-value markets?
The real issue: the 18m rule doesn’t “add a staircase”… it breaks the maths
The lazy argument is:
“It’s only a staircase, how expensive can it be?”
That’s amateur thinking.
The staircase itself isn’t the killer.
The killer is what it does to your core, your net internal area, and your layout efficiency.
You don’t “add” something.
You lose something.
Usually units.
Sometimes whole floors.
Sometimes the entire scheme.
Why the North gets hit harder than London
This is where most people miss the point.
A 5% NIA loss in London is painful… but survivable.
A 5% NIA loss in Sheffield, Leeds, Manchester or Liverpool?
That’s often the difference between:
finance approved vs rejected
viable vs dead
deal vs disaster
Because your income line (rent or sales value) is lower.
But your build costs?
They’re not lower enough to compensate.
So the margin gets wiped out.
The “viability chasm” is real (and it’s predictable)
Place Base highlights a danger zone:
18m–30m buildings
That’s the exact height band where most Northern city-centre schemes sit.
Mid-rise density.
Transport corridors.
PBSA blocks.
BTR infill.
And that band is where the second staircase rule hits hardest because it forces a redesign without giving you enough extra value to justify it.
The maths that actually matters (real-world enough)
Let’s take a typical 9-storey city-centre block around 27m.
Before the rule, you’d have:
1 protected staircase
lift core
compact circulation
After the rule?
You need:
2 protected staircases
more protected area
wider circulation solutions
service risers reshuffled
fire-stopping complexity increased
Typical impacts on pro formas:
1) NIA loss: 3%–8%
On a 6,500 sqm scheme, that’s 195–520 sqm gone.
That’s not “small”.
That’s entire apartments.
2) Direct build cost uplift: £600k–£1.5m+
Not just stairs. It’s:
structure tweaks
fire doors
smoke ventilation
partitions
services rerouting
compliance costs
extra QA and inspection
3) Programme delay: months
Redesign. Re-consultation. Re-submission. More lender scrutiny.
And delays don’t cost “a bit”.
They cost finance.
What happens next? Your yield gets punched in the mouth
Once you add the stair cascade, you typically see:
yield-on-cost dropping 50–150bps
stabilised returns weakening
refinancing assumptions becoming optimistic fantasy
And when debt is already expensive?
That’s where deals stop stacking.
That’s why the word “chasm” isn’t dramatic.
It’s accurate.
What it means in Sheffield (and the North)
Here’s the reality by typology:
Most at risk
Mid-rise BTR and PBSA (8–12 storeys / 22–35m)
Exactly what councils like.
Exactly what gets hammered.
Expect:
height reductions
redesigns
mothballed sites
land values being renegotiated down
Mixed impact
Office-to-resi conversions
If the conversion pushes you above 18m, the second stair can kill it — especially in skinny 1960s frames.
If you stay below 18m?
Still attractive.
Least impacted
sub-18m blocks (up to 6 storeys)
small blocks over shops
HMOs
BRRR stock
standard terraced housing conversions
Translation?
The rule pushes developers back toward low-rise density and smaller footprint projects.
And that means the big “city centre regeneration pipeline” gets slower.
The political truth: safety isn’t the argument — liability is
Let’s be blunt.
Government is not defending safety.
Government is defending risk exposure.
Post-Grenfell, nobody wants to be the minister who “relaxed safety rules” and then gets dragged through the press after the next fire.
So this isn’t about what’s optimal.
It’s about what’s defensible.
That means the 18m rule is unlikely to move quickly, even if it’s economically stupid.
So what should investors and developers do?
Here’s the operator’s playbook.
1) Stop chasing borderline mid-rise deals
If your scheme sits at 19–30m and the numbers are “tight”…
It’s not tight.
It’s dead.
Or it’s going to bleed you slowly through redesign and finance drag.
2) Focus on sub-18m models
Six storeys is the new sweet spot.
simpler fire strategy
better lender confidence
better plan efficiency
less regulatory friction
3) Expect land price rebasing
Landowners will complain.
Good.
They’ve been pricing land like it’s 2019.
This rule forces reality back into the market.
4) Use this as a filter for deal sourcing
If you’re sourcing land or packaging deals, ask one question early:
What’s the finished building height?
If it’s above 18m, the fire strategy becomes a core risk factor, not an afterthought.
Final thought: this rule doesn’t “remove homes”… it removes weak deals
That’s the part most headlines won’t tell you.
Some schemes die.
Some adapt.
Some shrink.
Some reprice.
The market doesn’t collapse.
It just punishes lazy underwriting.
And in the North, where margins are thinner, the punishment comes faster.
Want help stress-testing a Sheffield deal?
If you’re looking at a development site in Sheffield or South Yorkshire and you want a second opinion on:
viability
deal structure
exit strategy
rent assumptions vs build cost reality
Send me the numbers and I’ll tell you straight if it stacks or if it’s a future headache.
📩 Reach out via: marcinsakowski.com
or drop me a message on socials.
Source: Property Week – “Second-staircase rule halts 18,000 homes a year, says Place Base”
https://www.propertyweek.com/news/second-staircase-rule-halts-18000-homes-a-year-says-place-base
