Planning a new-build from scratch is not about “starting to put up walls”, but about making the right decisions before every decision starts costing money. If you align the plot, the design, the budget, the permits and the technical team from the beginning, the build runs smoothly; if not, changes, overruns and stretched timelines appear. This guide gives you a practical roadmap to do it properly, especially if you’re looking for a bespoke home in areas like the Costa Brava or Barcelona.
Before we talk about plans: what does “new-build” mean in practice?
In the real-estate market, new-build refers both to newly constructed homes (or brand-new, never lived in) and to “off-plan” developments. But when we talk about building from scratch, we’re talking about self-promotion: you lead the project, choose the design and manage the process with an architect, a technical architect/quantity surveyor and a construction company.
At Viñas Constructora we see it every day: the success of a bespoke home depends not only on the design, but on planning that turns that design into a buildable project, with defined specifications, clearly measured items and a realistic schedule. That’s the difference between “a beautiful idea” and a home delivered the way you expected.
Key differences between new-build and a second-hand home
This comparison is useful because it forces you to focus on what matters: risk, taxes, efficiency and warranties. With a new-build you usually gain on layout, insulation, systems and energy performance; with a second-hand home, you often gain a consolidated location and a faster move-in.
In terms of taxes, the general rule in Spain is clear: the purchase of a new home is subject to VAT (and, in many cases, stamp duty), while a second-hand home is taxed through the property transfer tax.
For warranties, the Spanish Building Act (LOE) establishes liability periods for material damage of 1, 3 and 10 years depending on the type of defect (finishes, habitability and structure).
The budget: how much does it cost to build per m² (and why the figure “depends”)
The million-euro question is the construction cost per m². The correct answer is a range, because a compact, single-level house does not cost the same as a home with a basement, large overhangs, natural stone, home automation, or a sloping plot. Even so, it’s possible to narrow it down properly.
As a market reference in Spain, it’s common to see ranges of €1,300 to €2,500 per m² (indicative total cost) depending on specifications and location.
PEM, contractor budget and total budget: don’t mix concepts
One of the most expensive mistakes is comparing figures that don’t mean the same thing. PEM (Presupuesto de Ejecución Material) covers direct construction costs (materials and labour), but it does not include professional fees, permits, taxes or margins.
That’s why professional bodies often publish PEM modules per m² (useful for approvals and estimates), which are not the same as a turnkey price. For example, in a 2025 reference table a value of €962.15 per m² is shown for a detached single-family home (in terms of execution material costs).
| Concept | What it includes | What it’s useful for | Practical tip |
|---|---|---|---|
| PEM | Direct construction costs (materials + labour) | Technical baseline, approvals, measurement comparisons | It’s not the “final price” |
| Contractor price | PEM + indirect costs + company margin | Comparing contractor offers | Require the same scope and specifications |
| Total (turnkey) | Contractor price + fees + permits + municipal charges + taxes + utility connections + extras | The real budget you must be able to afford | Keep a contingency reserve |
Indicative breakdown of the total budget (to plan without surprises)
Without falling into rigid formulas, a single-family home budget is usually distributed like this: construction as the largest item, professional fees (architect/technical architect), charges and permits, and a contingency buffer for unforeseen events.
- Construction: usually represents most of the budget (structure, envelope, systems, finishes).
- Professionals: design, site supervision, execution management, health and safety coordination, geotechnical study, topography, etc.
- Administration: permit, ICIO, municipal charges, connections and registrations (case-dependent).
- Contingency: a margin for price variations and decisions that change during the build.
At Viñas Constructora we tend to insist on the same thing: the budget that works is not the most optimistic one, but the one that leaves little room for improvisation. When the scope is well defined (specification, measurements and finishes), it’s much easier to close the price and meet deadlines.
New-build phases from scratch: what happens at each stage and what you need to decide
The safest way to move forward is by phases, closing decisions in blocks. That way you avoid changing things “once they’re already done”, which is when it becomes most expensive.
1) Defining needs and feasibility
This is where 80% of the outcome is decided. Define the brief (square metres, rooms, uses), lifestyle (remote work, guests, storage), and priorities (light, views, privacy, energy performance). At the same time, validate planning feasibility: what can really be built on that plot.
- Checklist: municipal planning rules, setbacks, site coverage, height, easements, access, orientation, slope and utilities.
- Critical decision: buying a plot without checking planning conditions is often the root of many problems.
With our clients in Costa Brava, for example, orientation and terrain influence everything from the structure to summer comfort, so it’s worth identifying this before drawing the first plan.
2) Preliminary design and concept: a design that already thinks about building
The preliminary design grounds the idea: layout, volume try, relationship with the surroundings and initial material choices. But what matters is that the design is buildable (without capricious solutions that drive up structural complexity or waterproofing requirements).
At Viñas Constructora we work closely with architecture and engineering so that aesthetics and technique align from the beginning: when details are resolved early, execution is cleaner and the final result shows.
3) Basic project and permit
The basic project is usually the basis for applying for a building permit. This is the time to review calmly: areas, regulations, alignments, and criteria for systems and efficiency. If you “push ahead” here without closing decisions, you’ll pay for revisions later.
4) Detailed design project and the real budget
In the detailed design project, construction solutions and systems are defined, measurements are produced and pricing can be accurate. This document is what allows you to compare contractors fairly: same scope, same items, same specifications.
5) Contracting: choosing a contractor and closing the scope
Choosing based on the “lowest price” is a trap if the scope isn’t locked. A healthy contract defines: specifications, brands or equivalents, deadlines, certification method, penalties and how changes are managed.
- Recommendation: always request a chapter-by-chapter budget, with clear measurements and explicit exclusions.
- Warning sign: too many lump-sum items without detail.
In exclusive home projects, the key is management: coordinating trades, planning purchases and ensuring each crew arrives when it’s their turn. That’s where a contractor with a clear methodology makes the difference.
Common new-build mistakes that drive up the cost (and how to avoid them)
Most overruns don’t come from “a huge unexpected issue”, but from small decisions accumulating without control. These are the mistakes that repeat most often.
Buying the plot without studying the regulations and the land
A plot may look perfect and still have limitations that change your home completely: true buildable area, access, easements, or a slope that requires retaining walls and drainage. Solution: a planning and technical study before completing the purchase.
A quick roadmap: planning checklist (to know if you’re on track)
If you want a quick way to self-assess, review this list. If you miss two or three points, you’re probably moving too fast.
- Plot validated: regulations, topography, geotechnics and access reviewed.
- Brief closed: needs, priorities and a realistic maximum budget.
- Measured project: defined specifications and comparable items.
- Clear contract: scope, deadlines, certifications, changes and penalties.
- Decision plan: what is decided and when (before it’s too late).
- Site control: technical follow-up, quality control and documentation.
When all of this is organised, building a house stops feeling like an “adventure” and becomes a managed process. And if you’re also looking for a unique home, with design and detail, planning is where peace of mind is won: at Viñas Constructora we’ve been clear about that since 2002, because quality doesn’t appear at the end; it is designed (and managed) from the beginning.
