An additional load must find a suitable path to the soil via the existing or new substructure.
Why does the foundation count?
A new one beam or column can concentrate existing loads in other places. An extension or roof structure can also add weight. The substructure is therefore part of the constructive assessment.
What information is useful?
Foundation plans, old calculations and available soil research help with the inventory. Known cracks, previous reinforcements and measurements may also be relevant.
Complete missing data specifically
Which recording or research is required depends on the project. First discuss the question with the structural engineer so that additional research fits in with the design decision.
Investigate the consequences of changing loads
An existing foundation has a history of load, maintenance and possible deformation. A new breakthrough can concentrate the load in a different location, while a build-up changes the overall weight and horizontal load. Therefore, collect the foundation file and available information about previous interventions. The aim is to determine what data are needed to assess the new situation, not to make a judgment based on age alone.
Distinguish observations from conclusions
Cracks, sticking doors and height differences are observations that can have various causes. Record location, progress and changes, but do not independently link one foundation cause to it. An expert can assess which additional research is appropriate for the question. Also discuss whether the investigation concerns the entire home or just a defined part. This prevents a limited conclusion from being used as an assessment of the entire building.
Your preparation in four steps
- Foundation and pile drawings
- Soil reports and soundings
- Previous interventions
- Data on new loads
Frequently asked questions on this topic
Is a CPT the same as foundation advice?
No. A CPT is a measurement of the properties of the subsurface. An advice connects soil data with the design question and building loads. Ask what studies are available and whether they are sufficiently appropriate for the location and the proposed structure.
Can an existing foundation be reused?
This requires an assessment of the existing foundation, its condition and the new load. Available drawings, pile data, soil surveys and previous reports can help. The mere fact that a building has been there for a long time does not provide an answer to a new structural change.
View the associated structural calculation, create your preparation list or take the guides and checklists along to the consultation.