One-Stop-Shop / Step-by-Step approach
The Step-by-Step renovation model is a widely diffused model of building refurbishment that consists in the repairs or replacement of different building components, such as the windows, plasterwork, roof covering, boiler etc. according to their life duration. One of the benefits of such an approach is that it gets the most out of each building component so that the initial investment is taken advantage of to its fullest.
The need of repairs or replacement of various components arises at different points in time. Inevitably, in the case of a complete retrofit building components that are still intact are renewed unnecessarily before time. In the step-by-step approach this can be avoided.
When applying a step-by-step approach, at least a rough overall plan should be made for all measures including those which lie in the distant future, before starting the work. In this way it can be ensured that an optimal end result is achieved in terms of cost-effectiveness, energy efficiency and quality.
The building owner, being it a private or public owner, in collaboration with the designer (planner) defines a planning for the renovation measures to be carried out and a timeline of implementation. The different contractors are involved by the owner in the renovation project in successive phases, according to the initial plan. The design risk is shared between the owner and the designer, while different contractors assume the construction risks associated to their tasks.
The following points should be included in such forward-looking overall planning:
- Chronological order of the measures: besides the expected time-point for the renewal of the individual components this also depends on the functional context. For instance, for window replacement with airtight windows, the installation of a mechanical ventilation system will also be necessary at the same time. Similarly, a heat pump with low temperature heating can only be installed if the heating load has already been largely reduced by means of insulation measures.
- Energy-relevant quality of individual building components: if the future quality of thermal protection of all building components is determined in advance, then the energy standard of the building that is achievable in the future can be ascertained by means of an energy balancing software program. The future energy costs and savings can also be determined with this. The transparent final goal provides motivation for implementing the necessary building component quality at each step.
- Building envelope – position of the airtight layer and insulation layer: if the approximate location of the airtight layer and insulation layer in the building component structure is specified, then it will be possible to find out whether the two layers can be continued without any gaps at the component connections as far as possible – even in the case of adjacent components which are not being modernised at the same time. This is the only way to achieve a building that is airtight and thermal bridge minimised as a whole.
- For subsequent measures, clarify in advance the points that must be given attention now: a good standard of thermal protection can only be achieved easily and cost-effectively if the interrelationships between measures that are not being implemented at the same time are kept in mind in advance. A typical example is that of a new balcony which is already joined to the (as yet) uninsulated wall of the house with a thermal separation. What at first does not seem to make sense in terms of construction prevents a massive thermal bridge at a later point in time when the wall insulation is carried out, and therefore makes it possible to realise the full potential for saving energy.
- Economic efficiency analysis (optional): if the energy savings achievable over the useful life of the measure are compared with the investment costs which are necessary for improving efficiency going beyond the level for maintenance alone, then it will be easy to recognise whether a measure is successful in economic terms as well. As a rule, this may support the building owner‘s decision to implement ambitious efficiency measures. In addition, the building owner can already plan for the necessary investment funds in the long term.
- The step-by-step renovation model was deeply studied and standardised within the EU project EnerPHit that developed the EnerPhit Standard based on the Passive House methodolgy and concept.
In conclusion, step-by-step modernization permits to building owners with limited financial resources to spread the investment costs for modernisation measures over a longer period of time. Moreover, the model permits to avoid unnecessary renewal or repair of components that are still good in terms of appearance and function. The extra costs for improving the level of thermal protection will often be moderate if energy saving measures are carried out at the same time as repair work that is necessary in any case. This speaks in favour of energy-related modernisation of each building component only when it needs to be repaired anyway.
"What” (value proposition)
The business model provides the following advantages for the customer:
- The individual building components have a different useful life duration. In general, not all building components will need to be repaired or renewed when building refurbishment is intended. With a step-by-step modernisation, one can normally avoid unnecessary renewal or repair of components that are still good in terms of appearance and function
- With limited financial resources, it allows to spread the investment costs for modernisation measures over a longer period of time
- Certainty that the agreed energy standard will actually be achieved
- Increase in property value through independent quality assessment
- The costs are spread over a longer period of time and are therefore easier to bear for the building owner.
- A step-by-step modernisation may be developed even without taking out a loan, i.e. only equity may be used. For many building owners, this is the most important reason for carrying out modernisation measures in succession.
- Full use can still be made of the remaining service life or residual value of components if necessary. In this way one can avoid unnecessary additional investment costs.
"Who” (target customer)
Public building owner or private building owners that intends to renovate their property over a long period of time, targeting high level of energy efficiencies and a certification of the results that will be achieved.
"How” (value chain, activities, resources)
The building owner, being it a private or public owner, in collaboration with the designer (planner) defines a planning for the renovation measures to be carried-out and a timeline of implementation.
The designer (planner) is the key player in this business model, because he/she is in charge of the whole renovation plan including different steps to be carried-out and the time schedule. The owner maintain an important role being responsible, in collaboration with an optional project manager, of the entire project. The different contractors are involved by the owner (eventually by the project manager, if any) in the renovation project in successive phases, according to the initial plan. The design risk is shared between the owner and the designer, while different contractors assume the construction risks associated to each of their tasks.
"Why” (revenue model and cost structure)
Cost structure for the main contractor:
The main cost for the designer are those associated with the training for the use of the tool, accreditation other than standard design activity costs (salaries, administration and support costs, marketing costs, etc.)
Revenue streams for the main contractor:
The designer (planner) is remunerated for the service provided. Additional revenues are related to the certification procedure (optional).