Construction Drawings for Beginners: Read and Understand

Drawing is an engineer's language - I want you to remember it this way!

It's a way of communication on site - between design and construction. Also when we explain something, we should use a drawing for it / sketch. Often 2 people talking about an element, or detail understand it a bit differently, while sketch / drawing makes it clear avoiding the confusion and misunderstandings.

2D drawing is still most common in construction process and it's very important that you can read and understand these drawings!

3D models are very useful, especially in more complex projects, but it's a still long way for construction to go fully digital and 3D.

Paper sizes:

A0 (841 × 1189 mm) - Typically you won't find these on site

A1 (594 × 841 mm) - Very common size for construction, often printed on site too.

A2 (420 × 594 mm) - Not very common size

A3 (297 × 420 mm) - This is the size of paper mostly use to print on site - Like explained in the lesson A1 will contain 4 A3 so if printed on A3 your scale will be 4 times bigger (A1 in 1:25 scale printed on A3 - would be in theory 1:100 - BUT I TREAT THESE DRAWINGS AS NTS - once not printed on original paper size - don't use scale

A4 (210 × 297 mm) - Mostly for specifications and schedules

Drawing should always contain the title block with Notes, Revisions and Legend. There should also be a thick border line around so once printed you are sure you're not missing any information.

Scale - Ratio between the drawing and the real object.

1:100 - 100 times smaller on the drawing

1:50 - 50 times smaller on the drawing and so on...

1:25

1:20

1:10

Sketches and some drawings / part of drawings might be NTS - not to scale

NTS - not to scale

Also, apart from NTS there might be a note about not using the drawing for scaling - in this case we shouldn't really use the CAD version drawing for our setting out works.

Status of Construction Drawings:

Preliminary drawings - for approvals and preliminary cost estimates - not for construction!

Tender drawings - issued for the tendering process - not for construction!

Issued for Construction drawings - that's the status we are looking for - we should only use information from drawings for Construction!

On site you might also find / produce Redline drawings - these are to capture any changes and deviation from the design.

Drawing number and naming convention:

PRN-ORG-00-L1-M3-S-0001

project name - originator - volume of work - level - type of information - discipline - drawing number

Most important for us in construction:

type of information:

DR - 2D Drawing

BS - Bending Schedule

PR - Programme

M2 - 2D Model file

M3 - 3D Model file

MS - Method Statement

Levels:

ZZ - multiple levels

XX - no levels applicable

B1 - Basement Level (B2 will be a deeper level)

GF - Ground Floor

Discipline / Role:

S - Structural Engineer (most important for construction phase)

A - Architect

C - Civil Engineer

M - Mechanical Engineer

L - Landscape Architect

Notes and Legend are very important piece of information and it's very important we read and understand these. It's a 'key' to the drawing giving you important information on how to read the drawing and what measures to apply on site during construction phase. Also used to keep the drawing 'cleaner' not to write all information - just using the symbols / abbreviations with the legend used to explain eg. C1 - column 1 dim. 400x400, FC - fire collar etc. Always go through notes and legend.

Lines have their own significance! There is a lot of information in the line itself.

3 main line weights:

'Dimensions' dimension line division ;) - thin line 0.18mm - grid lines, dims, hidden, hatches, centrelines

'Outline' object line division ;) - Visible Line - Object Line 0.35mm

'Section' cutting plane line  0.5-0.7mm

Lines in order importance:

Cutting plane line - section

Visible line - object

dimension line - dims, hidden, centreline, gridline

Above are main rules of using the line and there will be often information on the legend if any other type is used.

Designer can use scales, sections, details, line types, even colours on the drawing to make the information clear and redeable for us - the information should be passed in the most easy way, without repeating the dims and information.

Despite the design uses all the above to pass the information as clear as possible, there will be always communication with the design team - there will be RFIs send (request for information) FCR (field change request)

*Really recommend to draw simple elements to understand what information is needed to construct the elements. I left a links to software offering free trials - BricsCAD I'll leave for the next (intermediate) course as it will be good for you to have it then ;)

The easiest way to get the latest revision is working with CDE (common data environment) platfom provided by the client. There are many liek asite, aconex, viewpoint, 4 project and many more. The latest revision is uploaded by the client's document controller and available for everyone on the platform.

Client might have a drawing register with all disciplines - all drawings relevant to the project. This should be also available, nicely structured on one the CDE platforms (if used on the project).

Each drawing originator (discipline / trade) will have a drawing issue sheet regularly updated.

General Arrangements / Layout Drawings will be the most important for us. These are plan drawings showing us the element from top view - section through the building. We will be using these drawings for our setting out on site as there will be dimensions from the grid lines to all the elements. We also collect all other information necessary to fully understand how to build the element as on GA's there will be reference to other drawings, sections and details.

We always need full set of drawings regarding the element under construction!

* one from the losson is required to print in color, but typically we'll be using monochrome -that's an example showing a designer might actually require you to print in coulor to pass the information in the best way

Sections and Details will always accompany our GA / Layout Drawing to fully understand how to construct the element. Number of sections and details depends on complexity of the element, but should be enough to clearly show everything (like the balcony section in the lesson)

Structural Elevations Drawing will be mainly used by us during the cores construction. Depending on the method of construction there might be slipforms, jumpforms, traditional in situ, or precast cores.

We will be taking information about the levels and openings layout from these drawings, but always having the general arrangement for the particular floor with us!

Architect Elevations Drawing will typically show 4 elevations of the building focusing on the visual part - elevation type & colour rather than on structural part.

Architect - Grid Lines setting out. Grid lines - the most important lines for us!

Land Surveyor -  Topo survey with Job Control points - typically we'll get it from the client when the construction starts. On bigger projects there will be a survey team providing control for the job, or the outside survey contractor will be brought to site on regular basis to provide the information for setting out works.

Reinforcement (Rebar) Drawings & Schedules - by structural engineer - show how the rebar has to be fixed & installed depending on the structural element and how it has to be cut and bend (BBS - Bar Bending Schedule)

Drainage Drawings (Layouts, Details, Schedules) - these are often issued by a structural engineer, especially for internal drainage works, but often for external drainage within the plot boundary.

MEP - Mechanical, Electrical & Plumbing services

Temporary Works Drawings - These will show Falsework and Formwork and all temporary condition supports and propping systems used depending on the structure. They might be coming from the GW & RC Frame contractor for the simple elements and for more complex support systems they will coming from specialist TW contractor.

Specialist Contractor Drawings - Waterproofing, Lightning protection, Lifts, Balconies etc.

Landscape Architect Drawings - Showing the final levels, finishes type & street furniture.

Works Specifications and ITPs - Important documents to know, read through and understand giving us all information about the elements - procedures, materials, tolerances to achieve the required quality of final product.