Weld symbols
Drafting Tips

Weld Symbols – Understanding the basics

If you work within the construction industry – and steel construction in particular – you should be familiar with Weld symbols and their meanings. Weld symbols are used in structural drawings to show where the welds are to be placed and may also show the size, type of weld, number of welds, details about the weld and even details about the joint. In short they convey a LOT of information, and it is essential to convey this information accurately – which makes understanding Weld symbols vital.

First steps to getting your head around welds is to break down the Weld symbol itself:

Weld symbol_breakdown


1. FIELD WELD – When a ‘flag’ symbol is shown where the leader line joins the reference line, this is called a Field Weld and means the weld will be done in another location, ie. on site

2. WELD ALL AROUND – When a circle is placed where the leader line connects with the reference line, this indicates the weld is All Around. This means the weld extends all the way around the joint the arrow is pointing to. (The all around symbol should only be used when it is possible to weld all around a single surface)

3. ARROW – The Arrow points to where the weld information applies

4. SIZE OF WELD – The size of the weld is always shown to the left of the symbol

5. WELD SYMBOL – This shows the type of Weld required – In this instance a Fillet weld

6. LENGTH OF WELD – The length of the Weld (When it is not a continuous weld) is shown to the right of the symbol.

7. TAIL NOTE – This displays information about the process, specification, or other notes that do not normally have a symbol that describes them.

A key point to keep in mind when working with Welds is the side the Weld symbol is on. Symbols on the bottom of the reference line mean weld the side of the joint the arrow is pointing to. Symbols on the top of the reference line mean apply the weld to the other side of the joint, or the opposite side to where the arrow is pointing. Symbols on both sides of the reference line mean weld both sides of the joint.

Weld symbol_SIDE

These are just the basics for understanding Weld symbols, but they are also the most important! Make sure you keep these points in mind when working with Weld symbols and you should be sweet.

If you have any questions or something to add, please leave a comment below!

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Article written by:

Structural Revit Technician and BIM/Drafting Manager from New Zealand. Founder of revitIQ.com