OBRALIA 3DRequest assessment

Single-family house · Victòria dels Àngels

Two-storey single-family home with a pool in Salou (Tarragona), with clean volumes and 3D-printed concrete walls with a horizontal line texture. Project in design phase.

Single-family house · Victòria dels Àngels — Housing, Salou, Tarragona

Indicative visualisation; not a site photo.

Stage

  1. Design
  2. Permit
  3. Foundation
  4. Structure and walls
  5. Finishing
  6. Delivered

Description and key characteristics

Two-storey single-family home with a pool in Salou (Tarragona), with clean volumes and 3D-printed concrete walls with a horizontal line texture. Project in design phase.

Walls are designed with 3D-printed concrete: continuous layers with an inner cavity for services and reinforcement, fast execution and little waste.

Current stage: Design. Every project is validated before pricing and schedules are fixed in writing.

Common questions about this type of project

Answers selected according to the technology used in this project.

What is 3D-printed concrete?

A system that builds walls by depositing layers of concrete mortar from a digital model. It reduces formwork and allows free geometry.

It is an additive construction method: a robotic printer, guided by a digital model, extrudes a high-performance cement mortar layer by layer (in our case the Holcim TectorPrint family) and builds the wall shell without formwork.

The finished house is not printed; the hollow wall shell is. Reinforcement is then placed, the core is poured, services and insulation are integrated and the finish is applied. That is why we speak of a three-layer system: printed shell, reinforced concrete core and finish.

From digital model to finished home1
Digital model and design
2
Printing the shell
3
Rebar and concrete core
4
Services and insulation
5
Finishes and handover
  • Main advantage: free geometry (curves, undulating walls) without the cost of bespoke formwork.
  • Less labour and less formwork waste during the wall phase.
  • Everything remains subject to the CTE: the method changes how the wall is built, not the requirements it must meet.
Gantry printer depositing the wall layer by layer
Gantry printer depositing the wall layer by layer
Real printed wall, with the joint between sections visible
Real printed wall, with the joint between sections visible
Are printed walls structural?

By default the printed shell works as permanent formwork and the load is carried by a reinforced-concrete core designed to CTE DB-SE by a competent professional. No allowable-load figure is valid without its specific calculation.

By default the load is not entrusted to the printed shell. It acts as permanent formwork; vertical loads and horizontal actions are carried by a reinforced concrete core designed to CTE DB-SE (with DB-SE-AE for actions and NCSE-02 for seismic) by a competent engineer.

The choice is deliberate: printed material is anisotropic and its strength across layer interfaces is the hardest unknown to guarantee. With a conventional core, structural behaviour rests on a technology with decades of track record.

Wall section: three-layer systemEXTERIORINTERIOR①②③②④① Exterior finish② Printed shell (permanent formwork)③ Reinforced concrete core: carries the load④ Service ducts and interior insulation
  • Shell: forms the wall, acts as permanent formwork and receives the finish.
  • Core: rebar and concrete poured into the cavities; it is the load-bearing element.
  • No allowable load is valid without the specific calculation of each project.
Printed corner: each bead is one layer
Printed corner: each bead is one layer
Layered texture of the printed mortar
Layered texture of the printed mortar
What about the bond between layers?

It is the most delicate point: printed material is anisotropic and interface strength depends on the time between layers. We control and record that interval and take cores from a test panel before starting.

Each layer is deposited on the previous one and the bond depends on the time between them: if the lower layer has already lost moisture and tack, the bond weakens; if it is too fresh, it cannot carry the load and deforms. There is an optimal window that depends on the mortar, temperature, humidity and wind.

We control and log the interval between layers during printing and verify the result by taking cores from a test panel before starting. The scientific literature identifies interlayer bond and waiting time as key factors for the strength and durability of printed concrete.

Interlayer bond vs. waiting timeTime between layers →Bond ↑Controlled window← Too early: layer deformsToo late: weak bond →Qualitative sketch, no numerical values
  • Continuous logging of parameters (speed, flow rate, interval).
  • Surface measures, such as controlled moisture, if the interval grows.
  • The core reinforcement stitches the layers together.
  • Documented stop-and-restart plan if printing is interrupted.
Layered texture of the printed mortar (real detail)
Layered texture of the printed mortar (real detail)
Can you build with 3D printing in Spain?

Yes, with a project signed by a competent professional and proof of compliance with the CTE. Because no harmonised code exists for printed walls, each project goes through a specific validation.

Yes. Spain has neither a ban nor a special authorisation for the construction method: what is required is a project signed by a competent professional, a municipal building permit and compliance with the CTE (structure DB-SE, fire DB-SI, health DB-HS, safety of use DB-SUA, noise DB-HR and energy DB-HE).

Since no harmonised standard yet exists for printed-concrete walls, compliance is demonstrated through the alternative-solutions route the CTE allows, backed by tests of the material and of a test panel and by the calculation of the reinforced core, together with DB-SE-AE for actions and the NCSE-02 seismic standard.

  • Basic and execution design with a report justifying the solution.
  • Professional-body endorsement or supervision as required locally.
  • Tests under the UNE-EN 12390 series on samples from the batch and the panel.
  • A Technical Suitability Document (DIT) is an optional additional route we assess per project.
  • Each town hall may ask for extra documents: we check before applying for the permit.
What guarantees do you give?

Those required by Spain's Building Act (LOE) for any new home: 10 years structural, 3 years habitability and 1 year finishes. Any additional commercial guarantee is set by contract on each project.

They are those set by the Building Ordinance Act (LOE, Law 38/1999) for any new home, regardless of the construction method. The periods run from the handover (recepción) of the works.

Ten-year insurance covers structural damage to the home and is taken out by the developer (except for self-build for own use). The buyer has two years from when damage appears to claim. Any additional commercial warranty is defined by contract for each project.

LOE guarantees from handoverHandover1 year · finishes3 years · habitability10 years · structure0246810years
PeriodWhat it coversExamples
10 yearsMaterial damage to foundations, columns, beams, slabs and walls that compromises strength and stabilityStructural cracks, settlement
3 yearsDefects in elements or services affecting habitabilityDamp, service failures
1 yearExecution defects in finishesFlooring, paint, joinery
Is it cheaper than traditional construction?

With complex geometry the structure usually costs less than with formwork; with simple geometry it is comparable. The clearest advantage is time. Total cost depends on services and finishes, and we fix it in a closed quote after the study.

It depends on geometry. With complex shapes (curves, undulating walls) structure cost is usually lower because no bespoke formwork is needed; with simple, repetitive geometry it is comparable to a block or formed-concrete wall, and the advantage becomes time.

Services and finishes cost the same with any system, so the total saving is smaller than the saving on the structure. That is why we give a fixed, comparable budget.

CriterionPrinted wallsTraditional construction
Free geometryNo formwork surchargeBecomes very costly
Simple geometryComparableHighly optimised
Wall build timeShorterLonger
Labour on wallsLess, more specialisedMore
Track record and valuationShortLong
Services and finishesSameSame

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