Residential quarter · Villafranca de los Barros

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.

• 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.

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.

• 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.

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.

• 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.

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.

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.

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.