Sweco is looking for a talented and motivated Principal Mechanical Building Services Engineer to join our Maidenhead/London office to lead the delivery of sustainable, high-performing building services solutions and to act as a trusted advisor to our clients.

You will play a key role in shaping projects and people across our business, working within Sweco's four cornerstones: Client Focus, Best People, Internal Efficiency and Decentralised Organisation.

Our highly regarded mechanical, electrical and public health experts, sustainability teams and certification specialists collaborate with clients across the UK to transform vision into reality - with a unique blend of creativity and commercial pragmatism at the heart of everything we do.

What does the role involve?

You will take the role of lead mechanical engineer working on a wide variety of schemes and sectors including commercial, hospitality and hotels, residential and energy conservation.

As a Principal Mechanical Building Services Engineer, you will:

Client Focus

• Lead mechanical design on complex, multi-disciplinary projects from concept to delivery.
• Act as a principal point of contact for clients, understanding their drivers and translating them into clear design solutions.
• Facilitate early-stage engagement, develop briefs and lead technical presentations, workshops and design reviews.
• Drive value through low-carbon, energy-efficient and whole-life design thinking.

Best People

• Provide technical leadership and direction for project teams, setting high standards for design quality and innovation.
• Mentor and develop engineers and technicians, supporting professional progression and chartership.
• Contribute to technical excellence through internal forums, knowledge sharing and guidance documents.

Internal Efficiency

• Plan and manage mechanical work packages, ensuring delivery to agreed time, cost and quality.
• Champion effective use of digital tools (e.g. BIM, analysis software, collaboration platforms).
• Apply and improve standard processes, specifications and QA procedures to reduce rework and increase consistency.

Decentralised Organisation

• Take ownership of key technical decisions and support local teams to deliver projects for their markets.
• Collaborate with colleagues across offices and disciplines, contributing to market, client and capability development.
• Feed insights from projects and clients back into our wider business strategy.

What do you need to be successful in this role?

Qualifications and experience

• Degree in Mechanical Engineering or related discipline.
• Chartered Engineer (CEng) or equivalent professional status.
• Significant experience in mechanical building services design across multiple sectors and project stages.
• Proven track record of leading multi-disciplinary project teams and managing client relationships.
• Strong knowledge of UK Building Regulations, CIBSE guidance and relevant standards.
• Demonstrable experience in low-carbon and sustainable building services design.
• Excellent communication skills and commercial awareness.

Knowledge and skills

• Strong technical expertise in building services systems (e.g. heating, cooling, ventilation, electrical public health) and their integration with fabric and other disciplines.
• Thorough understanding of relevant regulations, standards and guidance (e.g. UK Building Regulations, CIBSE, BS/EN/ISO).
• Demonstrable experience in low-carbon, energy-efficient and sustainable design, including familiarity with relevant assessment methods where applicable.
• Competence with relevant design, analysis and BIM tools and an understanding of their role in integrated design.
• Strong analytical and problem-solving skills, able to balance technical rigour with practical, buildable solutions.
• Excellent written and verbal communication skills, including the ability to explain complex issues to non-technical stakeholders.

Behaviours

• Proactive, accountable and organised, able to manage multiple assignments and competing priorities.
• Collaborative, supportive and inclusive, with a commitment to developing others.
• Client-focused with sound commercial awareness and a focus on value.
• Aligned with Sweco's values and committed to delivering a sustainable, people-centred built environment.

Employee Benefits

• Flexible and hybrid working (Flexworks Policy)
• Competitive pension contribution
• Life Assurance
• Private Medical Insurance
• Company car or car allowance
• Discretionary Annual Bonus Scheme
• Payment of two relevant professional subscriptions
• 25 days holiday plus bank holidays (with the option to purchase up to 5 additional days per year)
• Cycle2Work Scheme
• Employee Assistance Programme (wellbeing, mental health, financial and work advice)
• Employee discounts via Sweco Benefit Select (Faircare)
• Salary Sacrifice Electric Vehicle Scheme
• We plant a tree for all new starters!

About Us

Transforming society together, we're planning and designing sustainable communities and cities of the future.

Solving the great societal challenges of our time is more relevant, demanding and inspiring than ever before. At Sweco, we bring together experts with different perspectives and skills to develop solutions that address the challenges of urbanisation, harness the positive power of digitalisation and make societies more sustainable.

We offer our clients a combination of global expertise and local presence, adapted to their business and reality. Our ambition is to be our clients' most relevant partner, working together to help them solve their challenges, today and into the future.

Sweco is committed to enabling all its colleagues to achieve a great balance between work and their other priorities, such as caring responsibilities, leisure activities, further learning or other interests. We offer flexible start and finish times, part time and hybrid working options so that you can flex your hours around your day to day needs.

Equality, Diversity & Inclusion

It's important to us that that all our colleagues thrive at work - we strive to have a friendly and inclusive culture which respects the contribution individuals can bring to Sweco. We aim to promote equality, inclusivity and diversity for everyone.

Here at Sweco we positively encourage applications from suitably qualified and eligible candidates regardless of sex, race, disability, age, sexual orientation, gender reassignment, religion or belief, marital status, pregnancy or maternity/paternity.

We have signed the Armed Forces Covenant to ensure those who serve or have served, and their families, are treated fairly. To find out more The Armed Forces Covenant - Our Commitments | Sweco UK .

We are an accredited Real Living Wage Employer which reflects our commitment to fair pay and support for all colleagues.

We are also proud to be a Disability Confident Committed employer, and will interview applicants covered by the Equality Act 2010 that opt into the guaranteed interview scheme on the application form and meet the minimum criteria for the role.

If I have a disability, can I get help (e.g. "reasonable adjustments") with the application process?

If you're an applicant with a disability that requires a reasonable accommodation to complete any part of the application process or are limited in the ability or unable to use the online application system and need an alternative method for applying, please contact GB_Function-HR-Resourcing@sweco.co.uk for assistance.

In order to address your request the following information is needed:

• Name

• The best method for contacting you (Phone or email)

• The position title

• Requisition/vacancy number

Upon receipt of this information, we'll respond to you promptly to obtain more information about your request.

Please note: we reserve the right to close vacancies before the advertised closing date.

Sweco UK&I have an internal resourcing team who are responsible for all recruiting activity. We have a Preferred Supplier List of trusted agencies who we work with on those "hard to fill" roles.

We have defined processes for recruitment applications and it is company policy not to accept speculative CVs. Any speculative CVs received into the business (whether to a manager or member of the resourcing team) will become the property of Sweco and the agency will not be eligible for an introductory fee.

Our Preferred Supplier List was reviewed in November 2025 and we are not looking to add any additional agencies. We'll be reviewing the PSL again at the end of 2026 and non-compliance with the above statements could be detrimental to you having the opportunity to be included.

Our Talent Community for experienced professionals is a great way to keep up to date with our latest news, insights, future vacancies, as well as gaining access to exclusive events hosted by our experts.

To learn more Join Our Talent Community - Sweco United Kingdom