An extension adds new loads and often connects to an existing facade. The roof, supporting structure and foundation together form the design. The connection with the main building deserves attention, even when the outbuilding is small.
New extension
An extension can combine a new roof construction, facade opening and own foundation. The calculation brings these parts and their connections together.
Prepare: Share the desired depth, width, roof structure and opening to the home.
Extension of an existing room
When expanding an existing space, the new and remaining supporting parts must be considered together. The connection to the old facade and foundation can be particularly decisive.
Prepare: Provide the current and new floor plan and the position of load-bearing walls.
Bay extension
A bay window protrudes from the facade and requires appropriate support. The structure can be supported via its own foundation, a cantilever or another designed load-bearing path.
Prepare: Indicate protrusion, height, facade openings and the intended material.
Garage
The roof and facades have to bear their load despite an often wide garage door. A possible storage attic or future use influences the principles.
Prepare: Indicate door width, roof type and whether the room will have an upper floor.
Shed, storage room and garden house
For an outbuilding, wind, roof load, anchoring and foundation are relevant components. A light building does not automatically have sufficient resistance to wind blowing.
Prepare: Share building system, location, height and method of attachment to the substrate.
Detailed explanation and request: Shed, storage room and garden house
Canopy and veranda
Open sides influence the wind action. The construction requires a check of beams, uprights, connections and anchoring, including any connection to the house.
Prepare: Indicate the free sides, roof covering and attachment points.
Carport
A carport combines an open design with relatively few support points. The stability and anchoring must match that design.
Prepare: Provide the column layout, roof dimensions and foundation layout.
Detached informal care home
An independent home requires a coherent design for the roof, floors, walls and foundation. Supplier details and location must also match in the case of a prefab delivery.
Prepare: Share the chosen construction system, supplier documents and soil data.
Detailed explanation and application: Detached informal care home
Extra floor on an extension
The existing extension may have been designed only for the current use. Additional walls, a floor and a roof require an assessment up to and including the foundation.
Prepare: Collect the original calculations and data on previous changes.
Detailed explanation and request: Extra floor on an extension
Data for the initial assessment
- Situation drawing and dimensions
- Desired roof and wall structure
- Connection to the existing building
- Soil and foundation information
From request to defined assignment
- Capture situation. Describe the location, existing condition and intended change.
- Review data. Discuss which documents are useful and what additional research is needed.
- Agree on scope. Record which checks, drawings and implementation phases are being developed.
- Fine-tune design. Please include changes in dimensions, material or use in the documents.
What determines the price?
The scope of the calculations, available data, required details and coordination determine the assignment. There is no single prize for this category that covers all situations. View the known starting prices and quote requests.
Frequently asked questions
Does a small outbuilding also need constructive attention?
Yes. Dimensions are only one factor; Wind, material, open sides, connections and subsurface also play a role.
Can an extension have the same foundation as the house?
This does not only follow from the type of home. Soil, load, existing foundation and possible settlement differences must be assessed.
What if the supplier already has a calculation?
Check which dimensions, location, loads and connections apply and which parts are not included in the scope of delivery.
Read more
Look up construction concepts · Compare materials · Prepare drawings