About Tweddell & Slater

Tweddell & Slater was created as a partnership in Penrith in 1989, evolving from a branch office of Michael Barclay Partnership, a London based civil and structural engineering practice. The two founding partners, Nicholas Tweddell and Edward Slater, continued working together as a partnership until May 2000, offering a comprehensive design service for all types of building structure.

Since May 2000 the practice has operated as Tweddell & Slater Ltd, a limited company with two directors: Stuart Mair and Reuben Gibson, both chartered engineers. Reuben Gibson joined the practice in 1998, bringing with him a wealth of experience in the design of building structures, particularly timber framed buildings. Stuart Mair joined the practice in 2005, bringing with him particular expertise in steel framed buildings, geotechnics and hydrology.

We are able to offer our clients expertise in a wide range of Civil and Structural Engineering services. Although the bulk of our work is in Cumbria and surrounding counties, we do carry out work throughout the UK.


Reuben joined Tweddell & Slater in 1998 and became a Chartered Engineer and full member of the Institution of Structural Engineers the following year. He became a Director at Tweddell & Slater Ltd in 2009 and specialises in building structures, particularly timber frame design.


Stuart joined Tweddell & Slater in 2005. As a Director, he is responsible for a variety of Structural and Civil projects.


Andy joined Tweddell & Slater in 2017. He is a Chartered Civil Engineer with over 15 years’ experience working on a variety of infrastructure, regeneration, geotechnical and structures projects. He became a Director at Tweddell & Slater Ltd in 2019 and is in charge of the Civil Engineering team.


Trevor is a Senior Engineer and joined Tweddell & Slater in 2014. He has experience across educational, industrial, retail and residential projects – including barns for conversion.


Andrew joined in 2007 as a Technician and specialises in infrastructure, drainage and highways. He is now a Senior Technician on the Civil Engineering team and is experienced in AutoCad, MicroDrainage, HEC-RAS software, and various 2D and 3D design packages.


Cathy studied Architectural and Structural Engineering at the University of Strathclyde and graduated in July 2014. She joined Tweddell & Slater that August and is currently working towards her chartership with the Institution of Structural Engineers.


Jane joined Tweddell & Slater in 2016. Jane is our Office Manager.


Rosie joined Tweddell & Slater in May 2018 as a Technician with a background using AutoCAD. She is a Technician Member of the Institution of Civil Engineers and her experience enables her to work with both the Civil and Structural team.


David is a Chartered Civil and Structural Engineer with over 20 years’ experience, specialising in Structural Engineering. His diverse career covers many sectors including residential, commercial and industrial. Projects include assessment of existing structures, renewable energy and nuclear decommissioning.

Tweddell & Slater Ltd

Consulting Civil and Structural Engineers
01768 865400
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