Offsite prefabrication and manufacture


Prefabricated models offer numerous benefits. Grant Hood, of The Cad Room explains the role they can play in construction…

The Cad Room have been involved with prefabricated modules and plant equipment for the last five years.  This is fast becoming the standard installation method on all construction sites where the design of the building allows for modules to be installed. The benefits include:

–      Reduced installation time on site;

–      Improved health and safety by reducing work at height;

–      Reduced waste material.

An engineered decision from reviewing the design and architectural structure will determine whether prefabricated modules for corridors, risers and plantrooms will work on the project.  Once that the decision is made you have already saved time and money.  Coordination still plays the major part in any off-site project, the same process and coordination philosophies still need to be adhered to to allow successful modularisation.

Plantrooms are the heart of a functioning building; it is where all the major plant is housed and where the most time is spent to maintain and repair the equipment and plant to keep the building in use.  We have produced many coordinated plantrooms and as such, this has led to prefabricated skids being manufactured offsite from our detailed dimensioned drawings.  Making use of the correct size and supplier of equipment is essential to achieve an accurately installed plantroom.

Risers are generally the easiest part of the building to coordinate and although not all risers can be prefabricated due to structural or architectural design, there are projects which require risers to be fully modularised.  Risers need to be accessed more than most as it is the main isolation point for each specific floor that needs distribution of services.  Fabricated risers make it easy to maintain and isolate if there is ever a problem.

Corridors are the primary routes for distributing services to all parts of the building as they are the first area to be considered for modules. Maintenance and access is very important when configuring a module as corridors are the most congested and require the most coordination.  The traditional install, albeit effective, has the risk of being changed on site, but with prefabricated modules, this removes the risk of change as the services are already fixed in place on a framed structure.  As the items are manufactured off-site, the level of detail increases to make sure all materials are drawn to real life sizes.

Modules come in three lengths, sized to which work with the ceiling arrangement.  These lengths range from 6m to 2.4m made up of 1.2m sections.  Generally, the module frames are made from slotted unistrut which comes in different sizes 41×41, 21×21 or 62×41, depending on the weight of the services to be installed on the frame will determine the size of unistrut to be used.  The installation of modules act like a puzzle — once you have a setting out point from the structure and making sure that the modules are labelled correctly — they should all seamlessly fit into place which reduces man-hours and also improves health and safety by minimising the amount of time one would have to work at height.

As we are now in the world of BIM, this process plays an important part into the efficiency of prefabrication and modules.  We have completed numerous prefabricated projects for all sectors.  Our experience in modules is advanced more than most, and we have completed over 1000 detailed manufactured drawings for offsite production to strict deadlines to meet site programme and deliverables.  We have created project specific templates to help with spool drawings which are required for fabricators to make the exact piece need for it to fit accurately — precision is key when creating spool drawings.

The Cad Room Ltd are specialists in coordinating and modularising services for prefabrication offsite.

If you have a project in mind, and would like to discuss the possibility of modules, we are more than happy to help.


Grant Hood  

The Cad Room


Please note: this is a commercial profile

Image details: 

Project: Carr Gate – Firing Range Building, West Yorkshire police station; Client: Interserve


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