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 infrastructure design.


Trevor is a Senior Engineer and joined Tweddell and 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 experienced in AutoCad, MicroDrainage and HEC-RAS software.


Mark is an experienced Technician and joined Tweddell & Slater in April 2014. He has extensive experience in precast concrete, in situ concrete and GRC. Projects include multi storey car parks, offices and apartment blocks.


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


Jane joined Tweddell and Slater in 2016. Jane is our Office Administrator.


Andy joined Tweddell and 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.


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

Tweddell & Slater Ltd

Consulting Civil and Structural Engineers
01768 865400
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