Guide
Shop drawings vs fabrication drawings
By 3D Design Studios ·
Shop drawings and fabrication drawings are both produced after the design is done, by or for the contractor who will make and install something. They are often used as if they mean the same thing. They overlap, but they answer different questions, and knowing which you need saves time at approval and in the factory.
Design drawings come first
The architect's and engineer's drawings say what is wanted: the appearance, the performance and the general arrangement. They do not usually say how each panel, bracket or cabinet will be made, because that depends on the system and the supplier the contractor chooses.
What shop drawings are
Shop drawings are the contractor's drawings showing how a designed element will be made and installed using a particular system. They are submitted to the designer for review, so the designer can check that the contractor's proposal matches the design intent before anything is ordered.
A typical cladding shop drawing package shows the panel layout on every elevation, the sub-frame and bracket setting-out, and details at windows, corners, floor lines and the roof. A joinery package shows elevations, sections and construction details of each unit.
What fabrication drawings are
Fabrication drawings are the drawings the factory or workshop works from. They give exact sizes, cuts, holes, edge treatments and part numbers for each component, often with a cutting list or schedule. They are less about approval and more about production: a fabricator should be able to make the part without asking a question.
The difference in one table
- Purpose: shop drawings show how it will be built and installed; fabrication drawings show how each part is made
- Audience: shop drawings go to the designer and engineer; fabrication drawings go to the factory or workshop
- Content: layouts, setting-out and junction details versus part sizes, cuts, holes and cutting lists
- Status: shop drawings are reviewed and approved; fabrication drawings follow from approved shop drawings
Who approves shop drawings in the UK
Under most UK building contracts, the contractor's design or specialist subcontractor submits shop drawings to the architect or engineer, who comments and marks them with a status such as A (proceed), B (proceed with comments) or C (revise and resubmit). Review by the designer does not usually move design responsibility onto them; check your contract for how contractor's design portions and approvals are handled.
What a good set includes
- A drawing register with numbers, titles and revisions
- Revision clouds and a revision history on every sheet
- Grid lines and levels that match the design drawings
- Clear notes of anything assumed or still to be confirmed
- Schedules that tie each component back to the layout
Where cladding needs extra care
On UK residential buildings, cladding is tightly regulated, especially on relevant buildings over 18 metres, where only materials meeting the combustibility requirements may be used. Shop drawings must reflect the designed system and the fire strategy exactly, including cavity barrier positions. The material choice and fire strategy belong to the designer and principal designer; the shop drawings must not drift from them.