Architecture
Building Components
Expert Advice: How to Read Patterns and Symbols on a Floor Plan
An architect decodes the complex elements in a floor plan so you know exactly what you're getting
For many first-time builders or renovators, being presented with a set of architect’s drawings can be like staring at hieroglyphics. But fear not – in the second part of our guide to reading floor plans, the meanings behind the various symbols and patterns you’ll see in architectural drawings are explained, so you can really understand what you’re looking at (and paying for!).
Read part one of the guide here.
Read part one of the guide here.
What are the patterns within the drawing?
A hatch is a pattern that indicates elements such as a tiling layout, cladding or roofing type. When an element is sliced in two, the cross section will show the contents of that element, such as concrete within a slab or steel within a beam. While you can find standard guides for this online, it’s wise to ask your architect which hatch represents each material, as standards can deviate between different practices.
A hatch is a pattern that indicates elements such as a tiling layout, cladding or roofing type. When an element is sliced in two, the cross section will show the contents of that element, such as concrete within a slab or steel within a beam. While you can find standard guides for this online, it’s wise to ask your architect which hatch represents each material, as standards can deviate between different practices.
What are the grid lines with numbers and letters?
Grid lines (normally shown as a dash) are added to construction drawings for several reasons. Each line will provide a coordinate (such as ‘the wall located along grid line A’), which can act as a datum or reference point for a builder to measure off. They can also denote a structural layout (for example the centre line of structural columns), or can be used to make it easy to communicate the location of an item within a building.
Grid lines (normally shown as a dash) are added to construction drawings for several reasons. Each line will provide a coordinate (such as ‘the wall located along grid line A’), which can act as a datum or reference point for a builder to measure off. They can also denote a structural layout (for example the centre line of structural columns), or can be used to make it easy to communicate the location of an item within a building.
What do the numbers and text next to symbols and titles mean?
You will see that on every page, numbers and letters will appear next to titles; such as ‘02-A302 Section B’. This indicates that there is a reference to another drawing – for example, ‘drawing number 2, on page A302’.
You may then find that on the plan or section within the drawing set, a symbol such as a section marker may contain the same lettering of 02-A302. This indicates that where that section marker is located refers to the second drawing on page A302. This is a simple cross-referencing system that architects use, so they can easily communicate where each drawing is located within the design. This also helps your architect talk to your builder about details within the design.
While it may not seem necessary on smaller projects, referencing is extremely important for larger projects where there can be hundreds of drawings that all need to be cross referenced with each other.
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You will see that on every page, numbers and letters will appear next to titles; such as ‘02-A302 Section B’. This indicates that there is a reference to another drawing – for example, ‘drawing number 2, on page A302’.
You may then find that on the plan or section within the drawing set, a symbol such as a section marker may contain the same lettering of 02-A302. This indicates that where that section marker is located refers to the second drawing on page A302. This is a simple cross-referencing system that architects use, so they can easily communicate where each drawing is located within the design. This also helps your architect talk to your builder about details within the design.
While it may not seem necessary on smaller projects, referencing is extremely important for larger projects where there can be hundreds of drawings that all need to be cross referenced with each other.
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What are those squiggly lines?
Each time a change is made on your construction drawings, a revision bubble will be made around the change. This often appears as a cloud-like form and is labelled with a letter or number.
This letter or code correlates to a description of the change, which will be listed within the title block or drawing label. This will include the date the change was made and exactly what the change is.
Revision bubbles are not only used to make it easy to identify changes in the design, but to keep track of ones that incur cost or time penalties. Each time an item on a sheet is updated, the revision number of the page will be updated – for example ‘drawing A718, revision A’.
The architect will send a transmittal to all stakeholders, whether it’s the builder, client or building surveyor, along with the drawing, so they have a record of the changes and the dates they occurred all on one sheet.
Each time a change is made on your construction drawings, a revision bubble will be made around the change. This often appears as a cloud-like form and is labelled with a letter or number.
This letter or code correlates to a description of the change, which will be listed within the title block or drawing label. This will include the date the change was made and exactly what the change is.
Revision bubbles are not only used to make it easy to identify changes in the design, but to keep track of ones that incur cost or time penalties. Each time an item on a sheet is updated, the revision number of the page will be updated – for example ‘drawing A718, revision A’.
The architect will send a transmittal to all stakeholders, whether it’s the builder, client or building surveyor, along with the drawing, so they have a record of the changes and the dates they occurred all on one sheet.
Why are the lines different thicknesses?
The weight or thickness of a line is used to convey not only an element’s hierarchy within a drawing (how important it is), but to determine its distance from other elements in the space. For example, a light or grey line may indicate the item is in the distance, while a heavy black line is often used for items that are cut through in a section or plan.
The heavier the line, the more solid the cut object is, so a brick wall will be very heavy but a benchtop made out of a lightweight material will be drawn in a lighter-weight line.
Lines that are either hidden or overhead are shown dashed.
The weight or thickness of a line is used to convey not only an element’s hierarchy within a drawing (how important it is), but to determine its distance from other elements in the space. For example, a light or grey line may indicate the item is in the distance, while a heavy black line is often used for items that are cut through in a section or plan.
The heavier the line, the more solid the cut object is, so a brick wall will be very heavy but a benchtop made out of a lightweight material will be drawn in a lighter-weight line.
Lines that are either hidden or overhead are shown dashed.
Why do the drawings keep saying to refer to other drawings?
Architectural drawings will often reference other key documents, such as fittings and fixtures schedules, specifications, general finishes schedule, and consultant drawings such as civil, structural engineering and geotechnical. While some items will simply be referenced, others may be drawn into the architectural set to ensure they fit within the design.
Architects rely on several specialist consultants to procure a building. The consultant’s design is taken into consideration and developed within the architectural design, and eventually assessed and read by the builder and building surveyor. This is why your architectural drawings will refer to other documents, such as tags stating ‘refer to engineer’s report for slab design’. This tells the builder that while the slab may have been drawn exactly as the engineer designed it in the architectural set, the builder should refer to the engineer’s report for the details on how to construct it.
In turn, the engineer’s report will then reference the geotechnical engineer’s report for construction recommendations that take into account the soil conditions.
Read more advice from architects
Architectural drawings will often reference other key documents, such as fittings and fixtures schedules, specifications, general finishes schedule, and consultant drawings such as civil, structural engineering and geotechnical. While some items will simply be referenced, others may be drawn into the architectural set to ensure they fit within the design.
Architects rely on several specialist consultants to procure a building. The consultant’s design is taken into consideration and developed within the architectural design, and eventually assessed and read by the builder and building surveyor. This is why your architectural drawings will refer to other documents, such as tags stating ‘refer to engineer’s report for slab design’. This tells the builder that while the slab may have been drawn exactly as the engineer designed it in the architectural set, the builder should refer to the engineer’s report for the details on how to construct it.
In turn, the engineer’s report will then reference the geotechnical engineer’s report for construction recommendations that take into account the soil conditions.
Read more advice from architects
Other elements worth knowing about
Some other elements you might see on a floor plan include:
Some other elements you might see on a floor plan include:
- Elevation markers: Normally a circle with two numbers inside – one is the sheet number and the other is the drawing number on that sheet. There is also usually a triangle indicating the viewing direction.
- Section markers: Similar to elevation markers, you’ll see two numbers and a viewing direction, but this time a line is added too. This line indicates where the building has been cut through to expose a particular section – a bit like a knife cutting through a cake and exposing the layers inside.
- Finished floor level tags: A finished floor level (abbreviated to FFL) tag is normally located near the middle of a room on a floor plan, and shows the level of the finished surface relative to the Australian Height Datum (AHD: sea level) or another nominated level. Often the ground FFL will be nominated at 0.00 metres high, with all other levels relative to this.
- Material tags: These are used to cross reference back to a legend or separate document that lists all the materials to be used in a build. The tag will be an abbreviation code, for example ST-1 would refer to Stone Type 1.
- Relative-level markers: Similar to FFL tags, these markers show the height of an element relative to AHD, or a nominated level.
- Dimension markers: These are used to show the measurements of each element in an architectural drawing.
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The heaviness or weight of a line tells you whether a wall is existing or if it’s a proposed new wall. Existing walls that are to be retained will often appear as solid black or have a heavy grey pattern (otherwise knowns as a ‘hatch’ in drafting lingo), while the proposed alterations (new work) may be denoted as two single lines with no fill, or they will be detailed with the structure drawn in. Make sure you check the drawing legend to be sure.
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