'In conversation' - with Brendan Collum, Founder & Director, IRS Construction on remediating 'Greenhouse', Leeds

Three façade systems, 172 occupied apartments, and what Gateway 2 means for the sector now - Brendan Collum, talks about what it took to deliver fire compliance in Beeston, Leeds.

Last month, IRS Construction reached Practical Completion on the façade remediation programme at The Greenhouse - an eight-storey, mixed-use Higher Risk Building in Beeston, Leeds. 172 occupied apartments. EWS1 compliant. Zero defects at handover. We sat down with Brendan Collum, Director at IRS Construction, to talk about what it took to get there; the technical layers of the building, the regulatory shifts mid-programme, and what thirty-plus years in façade replacement teaches you about getting work like this right.

Q: Greenhouse isn't a typical Higher Risk Building. What were you walking into?

"It's a building with a strong sense of history. In its earlier life, it was Shaftesbury House, a 1938 development recognised for its technologically innovative modernist housing for migrant workers. The building then took on its present form through the 2010 refurbishment, which was a major moment in its story. That was when it became Greenhouse and started to gain recognition as one of the UK's most awarded eco developments, thanks to an approach to ecological and social sustainability that was well ahead of its time. Features such as wind turbines on the roof, solar PV, ground-source heat and even a herb garden in the courtyard were all part of that vision, and people really responded to it.

Then Grenfell happened, and the cladding that helped the building win those awards turned out to be unsafe. So the brief from Rendall & Rittner was specific: remove every combustible element, replace it with a compliant system, achieve EWS1 compliance — but don't lose what made the building what it is. That's a different kind of brief."

Q: Structurally, you weren't dealing with one building. Talk us through what was behind the cladding.

"Three different structural systems in one envelope. Preserved 1930s brickwork on the lower floors. New concrete framing from the 2010 refurbishment above that. Lightweight steel frame at levels six and seven. Each one behaves differently — different loads, different tolerances, different ways of taking a fixing.

So, you can't take a single approach to the façade. We applied EWI render directly onto the existing brick on the lower floors. Render systems to the SFS within the courtyard. Rockclad rainscreen on the upper levels with differently coloured panels to keep the original 2010 design language. Three façade systems, one consistent finish. That's not ornamental. That's what the building demanded."

Q: Intrusive surveys flagged that the existing SFS at upper levels couldn't carry the new façade. How did the team respond?

"That's where collaboration earns its keep. This project was pre-Gateway 2 and tendered on a single-stage basis. The original spec assumed the existing SFS would take the new system. Once the surveys came back, that assumption didn't stand. So we sat down with the client team - Thomasons as the client contract administrator, Verteks as our structural engineer, and BTP as our architect - along with Homes England as the funder — and we re-engineered the structural solution together.

The thing is, everyone in the room wanted the same outcome — a building that complied, on a programme that worked, without losing the design. When you've got that alignment, the technical answer comes faster. We agreed an approach and started the works ahead of formal sign-off, so the programme kept moving, and got it through. That's what good collaboration looks like in practice."

Q: The Greenhouse stayed fully occupied throughout. 172 apartments. How does that change how you deliver?

"It changes everything, from day one. You're not simply building - you're working in someone's home. That has to sit at the front of your mind, not at the bottom of a risk register.

We had a dedicated Resident Liaison Officer right through the programme - a single point of contact across all 172 households, structured communication, additional support for vulnerable residents, and careful handling of access changes. That role isn't a tickbox. It's the reason 172 households trust you with their building for the better part of a year. Dan Ross, Project Manager for the Client on the scheme, said afterwards that the attention to detail from the site team was where IRS went over and above. I'll take that - because it came from somebody watching closely."

Q: The architectural identity of the 2010 design — how did you protect it?

"That goes back to the original brief from Rendall & Rittner. The building has an aesthetic that residents bought into. The differing-coloured Rockclad panels on the upper levels, the way the render meets the brick, the courtyard treatment — none of that is accidental. It was the work of the original design team, and people chose to live there because of it.

Our job was to deliver a fully compliant, fully remediated external wall system — and to do it in a way that, when you walk past the building, it still looks like itself. That's harder than it sounds. The detail across three façade systems must read as one consistent finish. The team got that right. The building looks like The Greenhouse — and is now safe for the future and the residents."

Q: Mid-programme, the regulatory landscape shifted. The Building Safety Act, the Building Safety Regulator, Gateway 2. How did that play out on this scheme?

"A few things happened in close succession. The Building Safety Act 2022 brought in a new regulatory regime for Higher Risk Buildings — Gateways, the Golden Thread, the Principal Designer and Principal Contractor duties. Greenhouse was awarded prior to these regulations and, therefore was not subject to the Gateway sign-off process. However, towards the end of our programme, the Building Control body signing off the works went into administration. And the Building Safety Regulator's evolving requirements meant the route to sign-off changed; we ended up needing a Hybrid Gateway 2 submission to get through to Practical Completion.

None of that was on the original programme. But it's the new reality of HRB remediation work, and the team that gets it across the line is the team that adapts without losing the thread. We worked closely with the design team and Thomasons to put together a compliant submission, the BSR signed it off, and we reached PC. That's the job now."

Q: What does that experience tell you about Gateway 2 specifically?

"Honestly? The introduction of Gateway 2 is a game-changer for the industry. It has fundamentally changed how high-risk residential projects need to be approached — and for the better. It means intrusive surveys and investigations have to happen early, so the design is informed by real building information and is 'right first time', rather than being developed on assumptions and corrected later, with the risk of high cost increases.

It means there is now a true golden thread of information - a clear, auditable evidence trail that the regulator can pick up at any stage and follow through from survey, to design, to construction, to completion. That information has to stand up to scrutiny.

It also means only genuinely competent contractors, designers and duty holders - those with the right systems, experience and accountability - will be able to deliver these projects successfully. The process is rigorous, and rightly so. It demands greater discipline, better planning and full transparency.

But that rigour is essential. Gateway 2 is about making sure everything is properly considered, coordinated and approved before work starts on site - reducing risk, improving safety and preventing costly mistakes later in the programme.

If a project like Greenhouse had been subject to the Building Safety Regulator gateway regime from the outset, significant time and cost would almost certainly have been saved, because key investigations, design decisions and compliance requirements would have been addressed upfront, rather than being identified and resolved during delivery."

Q: If you're sat opposite a freeholder or property manager about to start a programme like this, what's the one thing you'd tell them?

"Pick a contractor who understands the new process. Surveys come back with surprises — that's the nature of work like this. You don't want a contractor who hides them. You want one who picks up the phone, walks you through it, and gives you a route through. The cost of getting that wrong is your residents' trust, and you don't get that back easily.

Just as importantly, give residents the same level of attention you give to the technical aspects of the work. People are often more patient than the industry gives them credit for, but only when they feel respected. Communicate early, communicate often, and genuinely listen to their concerns. We are used to managing construction work and working hard to reduce the impact on residents' day-to-day lives, but for a student revising for exams or an older person who relies on walking, hearing or sight aids, changes to their living space while work is underway can be a very real source of worry."

Q: Last one. What's the IRS team taking forward from Greenhouse?

"A safe building. A team of partners we'd work with again. 172 households who put up with us for the duration and were honest with us throughout. Dan and James at Hollis and Thomasons, putting their names to the work afterwards. That's the part that matters.

Greenhouse is the kind of building that asks you to take a bit more care. The team did. We're grateful to everyone who delivered alongside us."

Read the full Greenhouse case study at irsconstruction.co.uk/the-greenhouse