John Guest: Using CAD Drawings (Part Three)

John Guest: Using CAD Drawings (Part Three)

Toby Howard-Willis, Technical Manager at JG Speedfit, discusses the importance of high quality CAD drawings, particularly when it comes to underfloor heating, and some of the consequences of when these fail to meet the required standard.


Professional builders already understand the importance of CAD designs, but not everyone pays the kind of careful attention to these that is often required for a successful project. In addition, there are still many cases of building projects when the CAD drawings used are actual physical sketches rather than bona fide CAD drawings.

Most of the time these are done by architects, although this is not always the case as some are still draw by hand for convenience. The issue with analogue drawings is that they cannot be easily amended in line with changing project requirements.

While amendments are relatively easily via CAD program, physical drawings need to be re-drawn, requiring additional time and effort which could be invested in more efficient activities.

Ordering of materials

When quantities of materials are ordered on the basis of the plan, any design inaccuracies will have a knock-on effect for the procurement of materials. To give a practical example, overfit boards and spreader plates require a precise square meterage in order to calculate the coverage of these fixing methods.

Even if there is a discrepancy of 20mm, this might mean a new box of spreader plates, incurring additional cost and potentially causing delays to the project.

Margin for error

When drawings are produced by hand, they tend to be less accurate and so the margin for error is increased. When builders are working with inaccurate drawings, it inevitably follows that any inaccuracies will be replicated in the finished product.

In the event of mistakes, remedial action will be necessary, undermining the profitability of projects.

Reputation is everything

In a competitive market, a business trades on its reputation. Poor drawings carry with them an increased potential for errors, which could cause irreparable damage to the reputation of a building contractor.

Professionally-produced CAD drawings, on the other hand, create a positive impression, convey professionalism and inspire confidence in customers, enhancing the reputation of builders.

Scalable solutions

When sending drawings electronically, PDF versions are better than photocopied documents. Unless copies are done professionally they will most likely be shrink-to-fit, which affects the scale of the design and therefore the overall accuracy of the drawing and the installation process.

Quite simply, a good CAD drawing can mean the difference between installation success and failure. An accurate drawing produced by experts using CAD software can save time, as well as thousands of pounds in labour and materials.

It can also play an important role in creating a positive impression with customers, since high quality drawings are easier on the eye and are generally more accurate, reducing the margin for error.

JG Speedfit provides a no-obligation, and free CAD design and quotation service. For further information click here.

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