Draw up a budget in which preparation, implementation and finishing are visible.
Estimate the complete project
An extension may require costs for design, constructieberekening, research, foundation, facade opening, shell, installations and finishing. Not every quotation contains the same components.
Identify uncertainties
Mark amounts that are still an estimate and indicate what still needs to be investigated. Use the budget tool to add up your own quotes and estimates. A calculation result does not replace the price agreement with the executor.
Distinguish calculation costs from the total renovation
The starting price of a structural calculation is not a construction price for the extension. Design, research, procedures, materials, installations and execution may be separate items. Therefore, first describe what help you are requesting from the structural engineer. Does it concern the new foundation and roof construction, or also the opening in the existing home? The quotation must make clear how the assignment is defined.
Which uncertainties influence your budget?
Missing foundation data or a changing design may require additional coordination. Make those uncertainties visible instead of writing them off as a fixed amount. Use provisional items recognisably and update the budget when quotes are available. In the budget planner you can combine your own amounts and a chosen reserve; the outcome is your scenario, not an automatic quote for the project.
Your preparation in four steps
- Preparation and research
- Foundation and shell
- Installations and finishing
- Still unknown items
Frequently asked questions on this topic
Are the rear facade opening and extension one calculation?
They can be part of one constructive assignment, but that must be agreed. The opening in the existing facade, the new roof and the foundation influence each other. Therefore, describe the complete plan and ask which existing and new parts are included in the quotation.
Can an extension be built without piles?
The choice of foundation is based on building loads, soil and allowable deformations. The situation of the neighbors or a general construction method is not sufficient justification for your own extension. Share available CPTs and foundation data and discuss what additional information is required for the choice.
View the associated structural calculation, create your preparation list or take the guides and checklists along to the consultation.