A roof calculation can concern the load-bearing beams, but also a new opening, extra weight or another use. In the case of a roof structure, the load must also be able to be transferred through the existing home to the foundation.
Additional rooftop storey
An extra building layer places a burden on the existing walls, floors and foundation. In addition to the new construction, it is being investigated whether the existing carrying road is suitable and where reinforcement may be necessary.
Prepare: Share construction drawings of all floors and the foundation plan.
Roof ridge raising
A higher ridge changes the roof shape and possibly the load transfer. Trusses, purlins, supports and connections must match the new geometry.
Prepare: Provide the existing and desired roof cross-section.
Dormer
With a dormer window, roof parts are often interrupted. The surrounding roof must be able to carry the loads around the opening and support the new construction.
Prepare: Indicate width, position, construction weight and supplier details.
Turn a flat roof into a sloping roof
The new roof introduces different support points and wind loads. It is being investigated how the roof will be anchored and how the loads will end up on the existing building.
Prepare: Indicate roof slope, ridge height and desired interior space.
Adjust hood construction
Removing or moving roof components can change the operation of the entire roof. An adapted supporting structure must also maintain cohesion and stability.
Prepare: Mark which trusses, tie beams, purlins or supports are being changed.
Roof trusses and purlins
Trusses and purlins transfer roof surfaces to walls or columns. The check includes strength, deformation, lateral support and connections.
Prepare: Share spans, distances, roof structure and material data.
Rooflight and roof glazing
An opening can cut through existing beams or roof panels. A designed edge structure directs the loads along the opening to suitable support points.
Prepare: Indicate opening size, product weight and position in relation to the beams.
Roof terrace
A residential function on the roof entails different usage loads than a roof that is only accessed for maintenance. Balustrades, tiles and planters also count.
Prepare: Share the layout, floor structure and location of heavy objects.
Green roof and sedum roof
A green roof adds weight that partly depends on water storage and the chosen structure. The constructive assessment uses product data that fits the intended situation.
Prepare: Ask the supplier about the saturated weight and the complete layer structure.
Solar PV panels and rooftop installations
Panels, ballast and installations cause local and distributed loads. Wind action and attachment to the roof are also part of the coordination.
Prepare: Provide an installation plan, ballast plan and product weights.
Detailed explanation and request: Solar panels and roof installations
Data for the initial assessment
- Roof plan and cross-sections
- Existing beam sizes and spans
- Weight and position of new parts
- Information about the construction under the roof
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
Is a roof strong enough if it previously had solar panels on it?
That does not prove that a new layout or extra ballast is suitable. Have the new situation assessed with the current data.
What weight counts for a green roof?
Use the relevant data for the complete structure, including the condition with absorbed water. The dry product weight alone is insufficient as a starting point.
Why is the foundation also considered when building a roof?
The extra load does not remain on the roof. It is drained to the foundation and soil via underlying components.
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