Stage 4 – Technical Design, the final step before Construction

RIBA Stage 4

Today we are looking at Stage 4 – Technical Design, the final step before Construction. Hopefully, you are following the series? if not, you can catch up on the previous posts here.

Having completed Stage 3 – Spatial Coordination, the procurement route now follows 1 of 2 routes:

  • “Traditional Contract” – The design team will continue unchanged into Stage 4 Technical Design, retaining control of the project. The build will be significantly more detailed, giving less chance of change.
  • “Design and Build Contract” – The design will be completed by main contractor, typically via their sub-contractors. Giving greater options for contractor savings and possibly increased buildability.

Is there a preferred procurement route?

At ADR Consulting Engineers we would always advise clients to engage with us as early as possible. Having a continuous, collaborative and matured design process should always yield the best information. However, we are flexible and dynamic in our approach and will seamlessly integrate with the design team.

Design and Build offer’s many benefits, and a significant amount of our projects follow the D&B route. We work closely with the sub-contractors to develop the very best value for the client. Leveraging buying power and maximising the contractor’s competency, we can develop a proposal that hits the performance and budget targets.

The mighty 300…

As previously mentioned, one of the key terms we use during the design process is LOD (Level of Detail). This can be best described as what detail you will be showing and how intelligent the model will be at a certain stage. We consider LOD 300 suitable for RIBA stage 4.


“The MEP Services are graphically represented within the project as specific systems, objects, or assemblies. Representative in terms of quantity, size, shape, location, and orientation.”

BSRIA Stage 4 visuals
BSRIA Visual representation of Stage 4 (LOD 300)

Whilst visually we can see the systems, objects, or assemblies in terms of quantity, size, shape, location, and orientation, the package of information should also compliment the model/drawings/output. Schedules, reports, briefs and specifications that are issued at information exchanges should be the same Level of Detail.

Stage 4 is the final step before we head into the construction process. As such, it is considered the last chance we have as engineers to firm up our design, and ensure all regulations and standards are being followed. Calculations should be finalised using industry-approved methods/software and the Stage 4 information should reflect a robust and buildable package.

There is also the potential that some Value Engineering has been introduced at this stage. VE items have pro’s and con’s, it is a complex process when considering contractor issued substitutions.

  • Does it perform equal or better than proposed?
  • What warranty does it come with?
  • Does it spatially fit?
  • What are the loading values?
  • Does it conform to all strategies? (fire/access/thermal/energy etc)

What makes us different?

We have worked extensively with clients, developers, installers and main contractors to ensure that at every step of the way, we Engineer Value into the project. This approach means that we are targeting the most efficient option from the start. It is with early engagement that we are able to identify the client’s needs, performance, and targets which are then tracked through the design process.

The next step is Stage 5 – Construction, finally getting to site. In the next post, we will look at how what information should be available during the construction process and what we can do as MEP Engineers to support the project.

Do you have a project coming up?

Why not get in touch with our team today to discuss? We offer free and confidential advice and are happy to support projects of all sizes.

Published by Lex Rouzee

A versatile Building Services Engineer with extensive experience within the construction industry, involving principally electrical bias design, installation, commissioning and testing. Significant experience within the building services sector has been gained from progressing through site installation, supervisor and now design and consultancy.

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