LPH 5 in new builds: Why detailed design decides on quality, costs and a calm building site
No matter how coherent a design is, only the detailed design shows whether a new build has truly been thought through in a robust way. In LPH 5, the fifth service phase of the German fee scale for architects (HOAI), an architectural idea becomes a building that can be built. This is precisely where it is determined how building components, junctions, materials and technical solutions fit together in concrete terms.
For clients, this phase is often less visible than the design or the building site. In fact, it is one of the most important steps in the project. Much of what later affects costs, construction time and quality is decided not on the building site itself, but beforehand, in planning. As an architecture practice in Wiesbaden, fbnSTUDIO accompanies new-build projects from the first idea through to completion and knows from experience: detailed design is the phase in which quality is concretely prepared.
What is detailed design (LPH 5) in a new build?
Design development sets the direction. In LPH 5, that becomes a buildable system. It is no longer just a matter of floor plans, elevations and spatial quality, but of concrete implementation. How are building components constructed? How do junctions work? How do the structure, building services and fit-out interlock? And where do details have to be resolved so that they work over the long term?
Detailed design comprises detail drawings at large scales, precise material specifications, construction details and the coordination of all specialist design disciplines involved in the project. The more cleanly these questions are answered in the detailed design, the less has to be improvised later. That is precisely where the great value of LPH 5 lies: it creates clarity before decisions have to be made on the building site under time pressure.
Why is a good design alone not enough?
In new builds in particular, it is often underestimated how strongly the quality of a project depends on its detailed planning. A building can be architecturally convincing and still show weaknesses in execution if details remain open.
Junctions between façade, roof, window and ground slab, transitions between shell construction and fit-out, or the integration of the technical trades often seem self-evident on the drawing. In reality, however, these are precisely the decisive points. If they are not planned properly, queries, deviations, change orders or unnecessary compromises arise on the building site. LPH 5 is therefore not just a more in-depth piece of diligent drafting, but the phase in which the design from LPH 3 and the approved planning from LPH 4 become a building that works over the long term.
Which details have to be decided in LPH 5?
Many problems in new builds arise at interfaces. Anyone who knows these typical points understands why detailed design demands so much care.
Windows and their junctions
A classic issue is windows and their junctions. Not only the window itself matters, but also its installation, sealing, airtightness, thermal protection and its integration into the façade and interior fit-out. If these points remain unclear, defects or later corrections quickly follow. A precise installation detail defines the sealing layers, the insulation of the reveal and the junction with the sun shading before the first contractor prices the work.
Roof, plinth and transitions
Roof junctions, plinth details, terrace thresholds and parapets are similarly relevant. What looks like a minor detail in the planning often decides later on durability, moisture protection and clean execution. The plinth is one of the most common sources of damage in new builds if the sealing, insulation and ground junction are not precisely coordinated with one another.
Building services and coordination
Building services must also be considered precisely in LPH 5. Service routes, shafts, plant areas and penetrations must not be developed in isolation from the architecture and the structure. The better these points are coordinated, the fewer conflicts arise later between the trades. A ventilation duct that collides with a downstand beam is quickly moved on the drawing. On the building site, the same collision means a work stoppage, redesign and additional costs.
Integrating fire protection in good time
Fire protection is another sensitive area. If it is not integrated into the detailed planning in good time, this often leads to elaborate adjustments, additional building components or unnecessary extra costs. Fire stopping, cladding and escape route details must be fixed in the detailed design so that they are properly taken into account in the tender and in execution.
How does detailed design make the building site calmer?
On the building site, it becomes apparent very quickly whether a project has been well prepared. When details are open, decisions are often made under pressure, by many parties at the same time and not always with the overall project in mind. This is exactly where misunderstandings, lost time and cost increases come from.
Good detailed design reduces this risk considerably. It creates a clear basis for tendering and execution. Works become more comparable, bids more reliable and processes easier to plan. Above all, however, it helps to resolve conflicts early, before they become expensive on the building site. For clients, this means more overview and fewer surprises. Not because a new build thereby becomes entirely risk-free, but because important decisions are already made where they can be dealt with calmly and systematically.
What does detailed design cost and what does it save?
Under the HOAI, detailed design is one of the most extensive service phases and accounts for a considerable share of the architect's fee. That is exactly why some clients ask whether they can dispense with it or reduce it, for example when a general contractor takes over the execution.
Experience shows that saving on detailed design is almost always a false economy. Without precise detailed planning, the contractors carrying out the work price on their own assumptions and risk allowances. Unclear scope boundaries lead to change orders, and quality decisions are then made not in the client's interest, but according to what is most economical for the contractor. The cost of a properly executed LPH 5 generally pays for itself through the change orders avoided and the greater comparability of bids. Added to this is the long-term value: a building whose details have been thought through incurs lower maintenance costs over the decades.
Why is experience in LPH 5 so decisive?
It is in detailed design in particular that the value of experience becomes apparent. Anyone who regularly plans new builds and sees them through to implementation recognises early which details may become critical later and where refinement is needed.
At fbnSTUDIO, we bring the necessary experience to this. We know that good detailed design does not consist of simply drawing plans in more detail. What matters is asking the right questions at the right time and resolving the interfaces properly at an early stage. That is why, from the outset, we start at the levers that matter most: the junctions, the material transitions, technical integration, fire protection and the coordination of the trades. In this way, many problems become visible before they cost time, money and nerves on the building site.
What do clients actually gain from good detailed design?
The benefit of this phase is greater than it appears at first glance. The advantages can be named specifically:
- Fewer change orders, because more points are clarified in advance and contractors price on an unambiguous basis
- More comparable bids, because the works are described more precisely and not every contractor has to make its own assumptions
- A better construction process, because the sequences and interfaces of the trades are clearly prepared
- Higher execution quality, because details are not left to chance or to improvisation on site
LPH 5 in a new build is therefore not an additional expense, but one of the most economically sensible investments in the project as a whole.
How are detailed design and material decisions connected?
In LPH 5, the material decisions that were still defined only as a direction in the design are also finalised. Floor coverings, façade materials, surface qualities and transitions between different materials must be described precisely so that the tender is unambiguous. A change of material in the floor covering needs a clean transition detail, an exposed concrete quality must be defined, and the joint patterns of tiles or façade panels must be planned before they are executed.
These specifications seem like small details, but they shape the finished building decisively. Anyone who leaves them to the building site gets random results. Anyone who makes them in the detailed design gets a building that matches the design down to the detail.
Detailed design for new builds in Wiesbaden
Anyone realising a new build in Wiesbaden and the Rhine-Main region benefits from detailed design that takes local conditions into account: the regional ground conditions for plinth and sealing details, the typical craft structures for a realistic division into trades and the requirements of Wiesbaden's building control authority for a smooth implementation of the approved planning.
fbnSTUDIO prepares the detailed design for new-build projects in Wiesbaden and the surrounding area with the aim that every detail is thought through before it is built. This care pays off in a calm construction process, reliable costs and a quality that lasts for decades.
LPH 5: Where quality is concretely prepared
In a new build, quality is decided not only in the design, but in the detailed design. LPH 5 is the phase in which a good idea becomes a building that is buildable, coordinated and works over the long term. Good detailed design saves money before it becomes expensive on the building site, and reduces change orders, uncertainty and unnecessary improvisation.
Arrange an initial consultation with fbnSTUDIO. We prepare the detailed design for your new build in Wiesbaden and the Rhine-Main region and ensure that your project is convincing in its details as well.
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