Structural calculationPrice on requestWhat is assessed?
A dormer window changes the supporting structure of the existing roof. This concerns the interrupted roof parts, their support and the way in which the dormer window dissipates its own weight and wind load.
A prefab supplier can calculate parts. Determine in advance who will check the connection to the existing roof, so that no parts are missing between the two assignments.
What data is needed?
The following information can be used to prepare the assessment. The structural engineer determines whether additional research is necessary.
- Roof cross-section and existing beam dimensions
- Dimensions and position of the dormer window
- Supplier details
- Photos of the inside of the roof
What do you receive?
Record the exact delivery in the quotation. Depending on your project and assignment, this involves:
- Assessment of the roof modification
- Calculation of shelter structures
- Required connection details
Discuss who will take care of the architectural development, supplier details and any temporary support. In this way, the components involved are coordinated.
Materials and drawings
The choice of materials and connections follow from the design. Read more about Structural timber and the difference between a architectural drawing and a construction drawing.
How does the process proceed?
You describe your project and share the available data. The assignment, any additional information and planning are then coordinated. Check it out complete step-by-step plan for all phases.
What does your assignment cover?
For a dormer, alterations to the existing roof determine the assessment needed. Show which rafters or purlins are interrupted and provide supplier information. Agree who designs support around the opening and the dormer connections.
Can I already order material?
Order structural parts based on the coordinated and current design data. A preliminary estimate is not a complete basis for this.
Is a site visit necessary?
That depends on the project and the available information. Sometimes drawings and photos are sufficient for the inventory; sometimes an admission or additional examination is necessary.
What happens if my plan changes?
Report changes before they are implemented. The structural engineer assesses whether calculations and drawings need to be adjusted.
From data to a detailed plan
Checklist for your application
| Given | What you prepare |
|---|---|
| Roof cross-section and existing beam dimensions | Gather the most recent available data and identify what is missing. |
| Dimensions and position of the dormer window | Gather the most recent available data and identify what is missing. |
| Supplier details | Gather the most recent available data and identify what is missing. |
| Photos of the inside of the roof | Gather the most recent available data and identify what is missing. |
- Describe your complete construction plan.
More daylight and space, with attention to the beams and tracks that are interrupted by the new opening.
- Discuss missing data.
The structural engineer determines which recording or additional information is required for the agreed assessment.
- Record order and delivery.
Agree on the calculated parts, drawings, price and planning.
- Match the effect to the implementation.
Use the current documents and have relevant changes reviewed before they are implemented.
Frequently asked questions about dormer windows
Does the dormer supplier's calculation cover my entire roof?
That depends on the supplier's assignment. His calculation can only relate to the delivered product. Record who assesses the existing roof construction, interrupted parts and connections. This way you prevent the transition between product and building from falling outside both assignments.
Does the location of the dormer window make a difference?
Yes, the opening can interrupt or load other roof components depending on its position. Therefore, share a drawn position, dimensions and a cross-section of the existing roof. Have changes to the location or width communicated to the designer involved.
Related constructive topics
Your project location
Provide the building address and share available drawings and photographs. Discuss whether a site survey is needed and which travel or investigation costs form part of the commission.