All articles · 5 min read

When does a floor plan need a professional — and when can you do it yourself?

The rule of thumb: if the drawing is used to decide something, you can make it yourself. If it is used to approve something or commit someone to a price, a professional needs to be behind it.

The test: decide or commit?

There is no list of "jobs that need an architect". But there is one question that almost always gives the right answer: What happens if the measurements on the drawing turn out to be 5 cm wrong?

If the answer is "then I move the sofa" or "then I buy one more box of tiles", you can make the floor plan yourself. If the answer is "then the contractor holds me to a price that does not add up" or "then the building application gets rejected", a professional needs to draw it. It is not the quality of the drawing that decides this — it is who carries the consequence of a mistake.

You can safely draw this yourself

• Layout and furniture placement. Does the dining table leave 80 cm behind the chairs? Can the bed be turned around? A measured plan of the room is enough.
• Ordering materials. Flooring, tiles, paint, skirting and ceiling panels are ordered by area and running metres, which you can measure yourself — just remember waste, typically 5-10% for flooring and 10-15% for diagonal tile patterns.
• Kitchen and bathroom planning. The layout choice — island or peninsula, sink under the window — gets made on your own plan. The actual order should be based on double-checked measurements.
• Initial contractor quotes. A contractor who gets a measured plan with areas and openings can price a realistic scope instead of guessing, and the spread between quotes narrows.
• Documenting the home as it is. Before a renovation, for an insurance case, or when the house needs to be described to an adviser.
• Sunlight and daylight conditions. How the sun hits the home through the day depends on orientation and geometry — you have both once the plan is drawn and the house is placed correctly relative to north.

In HouseSense you make exactly that kind of plan: scan the rooms with the iPhone's LiDAR, or draw them with your finger and enter the measured numbers. You get areas per room, a takeoff of wall and floor surfaces for contractor quotes, a 3D model and a daylight study. It is your own measurements that carry the plan — so it stands or falls on how carefully you measured.

A professional needs to draw this

1. Building applications. Extensions, dormers, conservatories, change of use, demolition. This kind of work needs approval from the authorities before it starts, and they will usually want a drawing set of technical quality — plan, section, elevations and site plan with scale and title block. An architect or a building surveyor delivers that.
2. Anything that touches the structure. If a wall is to be removed or broken through, a building surveyor or an engineer needs to look at the structure. No drawing, no scan and no app can determine whether a wall is load-bearing — not even an old archive drawing, because the house may have been altered since. If a load-bearing wall is removed without calculation, the consequence is not a crooked wall but settlement damage throughout the house.
3. Binding contractor quotes and contract documents. If contractors are to commit to a fixed price, they will want a drawing with a responsible sender behind it to hold onto — otherwise they add a reservation, and the reservation costs money.
4. Area corrections and area disputes. If there is disagreement about how many square metres were sold, a licensed surveyor needs to measure. Your own numbers can point to the problem, but they cannot settle it.
5. Boundaries, building lines and distance to neighbouring plots. Only a licensed surveyor can rule bindingly on where the boundary runs.
6. Fire, sound and moisture conditions for a change of use. If a basement or an attic is to become living space, requirements apply to escape routes, ceiling height and damp-proofing that an adviser needs to document.

The grey zone — and the cheapest way to handle it

Many projects sit right in the middle: you want to open the kitchen towards the living room, fit a larger window, or bring a covered terrace inside. Here the cheapest route is rarely either/or, but a three-way split:

1. You do the takeoff and the "as it is" plan yourself. This is the part that costs the most time and needs the least expertise, and it is the part you can do without paying anyone for it.
2. The adviser draws the change on top of your plan. Many design offices give a lower price if they get a measured starting point instead of having to drive out and measure. Ask directly what you save by supplying the measurements yourself — and expect them to spot-check a few.
3. The engineer calculates only the load-bearing part. A structural calculation for one beam over one opening is a far smaller job than a full project, and the price follows it down.

What you save is the drawer's measuring time — typically a couple of hours including travel and drawing up. What you cannot save away is the liability: whoever signs the drawing needs to have had the chance to check it.

Three mistakes that make a DIY plan useless

• The measurements were taken at one spot in the room. Walls are rarely plumb and rooms are rarely square. Measure each wall in two places, and check the diagonals — if they are equal, the room is square.
• The wall thicknesses were guessed. Measure them in a doorway or at a window reveal. With 8-10 internal walls each a couple of centimetres off, the house's overall length shifts by 20 cm.
• There is no note on how it was measured. Write on the plan what the numbers are, how they were taken and when: "internal measurements, taken with a laser measure" plus the date. Without that line, the recipient cannot know whether your numbers can be compared with the official areas, which are measured externally.

Ask the authorities, not the internet

The line between "you can do this yourself" and "a professional needs to" depends on what you want to do and on where you live. This article describes the principles, not the rules, and the rules differ from country to country and from municipality to municipality. Assume that anything changing the outside of the house, its area or its use needs approval from the authorities before work starts — and ask them what they want to see before you order a drawing. That question is the shortest route through the whole project.