The design brief: from what you need to square metres

Almost everyone who comes to design their house brings a list: three bedrooms, each with its own bathroom; an open kitchen; a study; a terrace for entertaining; parking for two cars. It is a good start. But a list does not say how big the house is, what has to sit next to what, what happens if the money runs short, or what can wait until later.

That is what the design brief says —in Colombia, the programa arquitectónico—: the document that translates how you want to live into spaces with a name, an area, relationships and a priority. It is short —a few pages— and it is the cheapest part of the whole project. It is also where a good share of the construction cost is decided.

Where the brief sits in the process

The Colombian reference for the profession, a 1989 fee regulation that is no longer binding but is still the vocabulary architects use, places it right before the drawing starts:

Two words in that sentence matter: the brief is studied and it is approved. It is not the list you bring, but what comes out of working through it with the architect, and you sign it off before a single floor plan is drawn. The same section requires the schematic design to be based on the client's needs, the codes in force and "the probable amount of the investment, estimated by mutual agreement". Needs, regulations and money: the three ingredients of a brief.

The questions the architect asks

A good brief comes from questions about daily life, not about rooms. These are the ones we ask, and it helps to arrive having thought them through:

1. 1Who lives in the house today, and who will in ten years? Children who grow up and leave, a parent who moves in, a grown child who comes back. The house outlasts today's situation.
2. 2What is an ordinary weekday like, and a Sunday? When each person gets up, where meals are really eaten, who cooks and for how many.
3. 3Does anyone work from home? A study for reading is not the same as an office where clients come in: the second wants to be near the front door and away from the bedrooms.
4. 4How many times a year do guests stay overnight? That answer decides whether the guest room is a bedroom or a study with a sofa bed.
5. 5What needs storing? Bicycles, tools, suitcases, bulk groceries, files. Whatever has no place ends up in a bedroom.
6. 6Are there pets, plants, vehicles? How many cars and how big, motorbikes, where the dog gets washed.
7. 7Who helps in the house, and do they stay overnight? It changes the service spaces and the routes through the house.
8. 8What do you dislike about the house you live in now? It is often the most useful answer of all.
9. 9How much do you want to invest, and over what period? Without this, the brief is a letter to Santa.
10. 10Do you plan to grow later? An upper floor, another bedroom, a pool. What is planned from the start costs far less than what is improvised.

What a brief contains

With the answers in hand, the brief is organised into five parts. None of them is optional:

• —The spaces, grouped by zone: living (living room, dining room, terrace), private (bedrooms, bathrooms, study) and service (kitchen, laundry, storage, parking, plant room).
• —The area of each space, in usable square metres —what lies between the walls—, with its reason: how many people, what furniture, what activity.
• —The relationships: what has to be next to what, what is better kept apart, and what has to be visible from where.
• —The priorities: what is essential, what is desirable and what can wait for a second phase.
• —The constraints: the budget, the timeline, what the zoning rules allow on the plot, and what the local climate asks for —in Cali and Jamundí, in south-western Colombia, above all shade and air that flows through—.

Relationships matter more than areas

Two houses with the same areas can work in opposite ways. What sets them apart is what touches what. That is why the brief includes a relationship table, which in a typical example looks like this:

This table is what the architect then turns into a bubble diagram —zones and routes, no walls yet—, and the first floor plan comes out of that. If the table is wrong, the plan comes out wrong even if every room is the right size.

A worked example

A family of four in Jamundí: two adults, two school-age children, one of the adults working from home. This is their brief in usable square metres. The figures are an example to show the method, not a recommendation or a regulation.

Here is the most common mistake of all: believing the house measures 109 m². It does not, because what has no room name is missing:

Between the list and the house there are 35 m² more, a third of what was asked for, without adding a single room. And that is without the terrace or the parking, which are also built and paid for, even if they do not always count the same way under the zoning rules. If the budget was worked out on 109, it is short before anything starts.

The brief against the budget

With the built area estimated, the first honest sum can be done: square metres times a cost per square metre for the kind of building you want. We do not give that figure here because it changes with the city, the construction system, the finishes and the date; the public references, with their cut-off dates, are in how much it costs to build per m² in Colombia. And what is not construction has to be added on top: design, permit, technical studies. They are in the twelve items people forget when budgeting.

If the numbers do not add up —and the first time they almost never do—, there are three levers, and only three:

• —Less area. Each space is checked against how it will really be used. Square metres asked for out of habit almost always turn up.
• —In phases. What was marked "can wait" is planned for and built later. It only works if the first phase already leaves the growth ready.
• —A different specification. Finishes, construction system, doors and windows. It is the easiest lever to pull and the one you notice most when living in the house.

What does not work is the fourth option everyone tries: keep the brief, keep the finishes and hope the build comes in cheaper. Why it does not is explained in why construction goes over budget.

Growing later without undoing what was built

Many people build in phases, and that is fine. But growth is designed into the brief, not when the money arrives. Three questions to settle from the start:

• —Which way does it grow? Sideways, if the plot and the zoning rules allow it, or upwards.
• —Can it take it? If it is going to grow upwards, the structure and foundations are designed for that upper floor from the first phase. What happens when they were not is in adding a second storey.
• —How do you get there? The future stair, the future corridor and the future services are left with their space reserved. Otherwise growing means demolishing.

Whether the house should have one storey or two is a decision that largely comes from here: the area against the size of the plot and what the zoning rules allow. It is not decided by taste before the brief exists.

The mistakes we see most often

• —Adding up rooms and forgetting circulation and walls. It is the mistake in the example: a third of a house that is not on the list.
• —Forgetting the service spaces. Laundry, storage, bins, the water tank and pump, the meters, the pool plant room if there is a pool, room for the car to manoeuvre. They are not attractive, but they take up square metres, and if they are not in the brief they end up where they get in the way.
• —Oversizing. The formal living room nobody uses, the guest room for two nights a year, a bathroom per bedroom when two bedrooms could share. Every square metre is built, furnished, cleaned and maintained for ever.
• —Copying someone else's brief. The brother-in-law's house or the one in the magazine were made for another family, another plot and another climate.
• —A brief without a budget. A house gets designed that cannot be built, and the schematic design gets paid for twice.
• —Changing it halfway through the schematic design. See the next point.

Why it pays to close it before drawing

Changing the brief once there are drawings is expensive, and the fee regulation says so plainly. A change that "substantially modifies the schedule of areas and needs" is treated as new work, and the schematic design is charged again (Decreto 2090 de 1989, section 1.2.3.2). The same regulation makes the other side clear: if the schematic design did not meet what the owner asked for, that is not a change of brief.

In other words, a signed brief protects both sides: you, because it fixes what the design has to achieve; the architect, because it separates their mistake from a change of mind. And when there is no certainty about the plot or the brief, the same regulation provides an earlier step, the concept sketch (esquema básico), to clear them up before the schematic design begins.

What we cannot tell you here

• —Minimum areas per space. For a house that is not social housing, we did not find a national regulation setting how big a bedroom or a kitchen must be that we could read and cite. Where local requirements exist, each municipality's rules set them, and they are checked with the plot in hand. The areas in this article are an example.
• —How much circulation should take up. There is no official figure. The 20% and 10% in the example are our own rule of thumb for a first estimate.
• —What your house will cost. It depends on your brief, your plot and the date. That is why we link to dated references instead of inventing a figure.

What to bring to the first meeting

• —Your list, as it is. Messy is fine.
• —What you like and dislike about where you live now, with photos if you can.
• —An honest idea of the total budget and the timeline.
• —The plot details: address, title certificate and, if you have it, the zoning statement. If it is in Cali or Jamundí, what each one requires is in Cali's POT and your permit and in building in Jamundí.
• —What you expect to do in five or ten years.

The brief is the part of the design where you decide most and where changing your mind still costs nothing. If you are starting out and want to put yours in order before anything is drawn, begin with a free fifteen-minute first call.