When appointing an architect to carry out design work on your home or project, pretty much the first thing (apart from briefing, talking and discussing the project) needed is an accurate set of plans and elevations.

These are in-depth measured drawings showing the building to scale, including wall thicknesses, sanitaryware positions, window heights as well as widths etc. These also include elevations and sometimes cross-sections of the building.

They differ to estate agent plans in many ways, but mostly in the level of detail and accuracy. A typical estate agent plan is not drawn with any where near as much care, sometimes bits of wall or doorways missing etc. TSA has tried a few times to work up design options based on agent’s plans but it usually causes more issues than the saving is worth. Agent plans are representative and perfect for what they are intended, but should not be relied upon for accurate information. For example in this agent plan below, the kitchen/utility/study projecting wing to the ground floor rear actually is not perpendicular to the main house, and you will see there is no connecting door between the hall and breakfast room, when in fact there is one. It is the detail that is lost, but sometimes that can have a big impact upon the design development.

Typical estate agent plans


For most dwellings about half a day is spent on-site measuring the building. This involves drawing out the rooms by hand, roughly in scale with each other (Which is a skill in itself!) and then going round methodically taking measurements, horizontal and vertical of each fixed feature. During this time the loadbearing nature and history of the walls, floors and alterations can be determined.

Sample architect survey notes

Back in the office, the plans are drawn up on the computer drawing software (CAD). Using the floor-ceiling heights, floor thickness measurements, the window sill and head heights taken, the elevation drawings of the building can then be worked out. These are then an accurate scalable set of information ready for use in designing the alterations/extension etc.

An outline site plan is downloaded from the Ordnance Survey which is necessary for a Location Plan (part of any planning application). This is not always very accurate as it is generated from aerial surveys. It does give a good impression of the site however, and on certain projects these are embellished with additional information gathered on-site and some check dimensions.

For complex, or ‘wobbly’ buildings or those with specific needs for accurate site information (For example, Conversion of a farmyard, sloping sites, new-build sites, or areas that need neighbouring buildings drawn out like in tight urban spaces) then a topographical survey is needed. Professional surveying companies are then involved. They can take on the building measurements as well, so while their surveying cost is usually more than the architect’s building survey, you get the building, the site and all the height levels. The architect’s cost is not payable then, so the actual uplift in cost is not usually that great.

Typical topographical surveys

However, while the information is accurate and clear, it is often not  very refined in terms of its presentation. When using such services therefore TSA allows for a portion of time to ‘beautify’ these drawings with graded line weights/thicknesses, some shading, additional detail and laying out on sheets in a logical manner. This time is not wasted however, as the ‘As-Existing’ drawings go on to form the backbone of all future drawing work, which in turn is therefore presented well. A well-presented and clear, legible set of drawings goes a long way to form a persuasive argument more likely to succeed through the planning process.