A complete review of the foundations is required, looking at their dimensions, depth and nature. Once this review has been completed, a new load distribution calculation can be made to determine whether any strengthening will be necessary. Dependent on the depth of the foundations, they may also need to be underpinned, insofar as this is feasible.
2.3.2.2. Checking the existing structures
> 2.3.1.3 p. 204
Once the project has been defined, a detailed load distribution calculation for the new situation needs to be made, on the basis of which all existing structures need to be checked. The roof requires particular attention, as the loads it will be subjected to on account of the refurbishment will obviously be much higher: insulation material, triple-glazed windows and possibly solar or PV panels. The precautions mentioned above for a new building naturally also apply to a refurbishment project. .
2.3.2.3. Eliminating thermal bridges by cutting through floors and interior walls In order to achieve insulation continuity, it may be worthwhile - when using inside insulation - to completely isolate the facade from the inside structures (floors and interior walls). This can however have numerous consequences. The stability of the facade itself must be ensured: it needs to be anchored through the new insulation layer into the load-bearing structures. What sort of anchoring is used is dependent on the type of structure: •
Where the anchoring is into concrete structures (columns, beams, floors in precast slabs or poured in situ, chemical anchor systems will be required. If the concrete is already very old or in a bad state, it is wise to carry out tensile tests to determine the pull-out resistance of any anchor. Dependent on the results, the number, diameter and installation of the anchors can be determined by a structural engineer.
•
Where the anchoring is into floors consisting of hollow core slabs (in French: hourdis), it is desirable to partially uncover the slabs around the anchoring points and cut notches in them, into which the anchor rods are
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