Getting planning permission for our ‘XXL-sized’ home extension without having to field multiple objections from disgruntled neighbours was a major milestone. Living in a small village means local sensibilities can easily become ruffled, so it probably helped that the design was ‘in keeping’.

Looking at Projected Costs

Unlike a self build project where, by this point in the proceedings, huge sums would have been forked out to acquire a building plot, our financial outlay has so far been minimal, with the cost of applying for planning more than covered by the value the consent has added to the property. So this is a good time to take stock and revisit earlier assumptions about projected costs and viability.

The trouble is, coming up with an accurate total build cost figure at this stage is inevitably going to be a little hazy. So for the time being, the project is based on a rough rule of thumb guide of between £1,000 and £1,500/m2.

Finding Design Inspiration

Before the build cost sum can be calculated with any degree of precision, the design must first be refined. One of the most enjoyable phases of any build is the process of researching materials, mulling over all kinds of interesting products and perusing the latest trends in kitchen and bathroom fittings.

I was keen to learn more about some of the more recent arrivals on the domestic construction scene, such as through-coloured monocouche renders and liquid anhydrite floor screeds, and also to get up to speed on the various options for underfloor heating, woodburning stoves and timber cladding. Then there’s the task of assessing the offerings from myriad suppliers of bi-fold doors — we plan to incorporate two pairs in the extension.

Preparing Plans for Building Regulations Purposes

With the process of refining the design underway, the next major hurdle is preparing the building control application. This requires a fairly extensive set of detailed drawings, which can also be used for getting the job accurately priced.

Those of us of a certain age may recall a time, back in the day, when complying with the Building Regulations was a lot simpler. As long as the building work complied in terms of structure, drainage and fire safety you could be pretty sure that the building inspector wouldn’t cause you too much grief. Work would commence on site a couple of days after submitting a simple Building Notice application to the council.

Fast forward to today and the Building Regulations have morphed into a formidable creature with enormous scope and complexity, particularly when it comes to complying with energy efficiency targets. This means that for anything other than the smallest jobs it’s advisable to make a ‘full plans’ application.

Flicking through Homebuilding & Renovating back issues I came across an article by former Editor Jason Orme pointing out that it’s a common mistake for people to rush this stage and start the build too soon, skimping on detailed plans and storing up trouble for later. Going the extra mile to get a full set of drawings produced means that any non-compliance issues can be rectified in advance, rather than risking major hold-ups later.

Using a Software Package

Drawings for Building Regulations purposes need to contain a great deal of information to illustrate how each part of the build is going to comply with the rules (which are contained in the Approved Documents — see Although it’s often feasible for applicants to produce drawings for planning applications on a DIY basis, when it comes to those destined for building control it’s a far more demanding ball game, and hence not normally advisable.

That said, if you’re reasonably clued-in to the technical requirements and have a few days spare, it might be worth a shot — particularly if you’re likely to undertake similar projects in future.

Given our budget, I was keen to produce my own drawings, but traditional hand-drawn plans seem positively prehistoric today, so this would be a good opportunity to learn a valuable new skill with a suitable CAD package. But which one?

I needed a plain-vanilla program for drawing straightforward scale plans and elevations, ideally incorporating the facility to add text and import images. But as a CAD ‘learner driver’ I was also going to need some decent online tutorials and technical support.

I decided to call up an old friend at Leeds Council Building Control, who cautioned against cheap software: “You can struggle to make it work, and the pretty pictures on the box will look nothing like what you want,” he said.

AutoCAD seems to be the choice of many professional designers, although it’s not cheap, costing well over £1,000. But even top-end packages aren’t without their detractors posting critical reviews, and it’s a lot of money to risk when, for not much more, we could pay an architect to do the job for us, saving a lot of hassle. So what to do?


Front, side and rear views of the new elevations on Ian’s extension

  • Babajide Ibiayo

    Thanks Ian, for this post, goes to show that you really don’t need expensive software to produce full design plans that comply with building regulations and approval

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