Structures

Floor strengthening — securing and load transfer

Q: Is the strengthening visible?

It depends on the technique: a composite slab cannot be seen from below, a section added underneath can stay exposed or be boxed in.

Q: Can I stay in my home during the works?

Often, yes, outside the room concerned and the one below, which is propped during the works.

Q: Is approval needed in a co-owned building?

Yes, when the floor is a common part, which is generally the case: the works go to the general meeting, with the structural calculation.

Strengthening timber, concrete and steel-joist floors: change of use, sagging floors, renovation.

A floor needs strengthening when it must carry more than it was designed for, or no longer carries what it should: deflection, vibration, decayed or corroded beams. The solution depends on its structure, timber, concrete or steel joists, and on the structural engineer’s design.

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Adapting a floor to new loads and uses

What is floor strengthening?

A residential floor is designed for an imposed load of 1.5 kN/m² (Eurocode 1); offices require 2.5, shops 5. Converting a home into offices, fitting out an attic or installing a library, a cast-iron bath or an indoor pool therefore means checking, and often strengthening, the existing floor.

Techniques follow the structure: doubling or sistering the joists of a timber floor, a composite concrete slab cast over the floor, steel beams or sections added underneath, repair of corroded joists in a jack-arch floor, common in older buildings in Nice. Strengthening is always preceded by investigation and a structural calculation.

When to strengthen a floor

Every case starts with investigation and a structural calculation.

Sagging or bouncy floor

Visible deflection, a springy feel, cracking floor tiles.

Change of use

A home converted into offices or a shop, an attic fitted out.

Heavy point load

Library, bath, tank, technical equipment.

Decayed timber

Joists weakened by insects or damp.

Corroded steel joists

Jack-arch floor whose steel joists have rusted.

Stairwell or opening

A stairwell cuts joists or reinforcement that must be picked up.

Our expertise

Know-how in special works

We strengthen timber, concrete and steel-joist floors, carrying out the solutions designed by the structural engineer.

Our key skills

Strengthening of timber and concrete floors
Load transfer
Installation of beams and steel sections
Strengthening of existing structures
Work on occupied sites

How a Sirianni Travaux project unfolds

Investigation and survey

Type, spans and condition of the floor, current and future loads.

Structural calculation

The engineer sizes the strengthening and the sequence of works.

Propping and works

Propping where needed, then installation of the strengthening.

Handover

Inspection of the strengthening before the props are removed.

Frequently asked questions

When should a floor be strengthened?

When it sags, vibrates or cracks, and before any change of use or significant new load. A structural calculation decides.

Which floors can be strengthened?

Timber floors, concrete floors, solid slabs or beam-and-block, and older floors with steel joists and brick jack arches.

Is the strengthening visible?

It depends on the technique: a composite slab cannot be seen from below, a section added underneath can stay exposed or be boxed in.

Can I stay in my home during the works?

Often, yes, outside the room concerned and the one below, which is propped during the works.

Is approval needed in a co-owned building?

Yes, when the floor is a common part, which is generally the case: the works go to the general meeting, with the structural calculation.

A consolidation or foundation project?

Get a tailored assessment for your special works. Tell us about your structural issue or your project — we will get back to you after analysing the structure and its surroundings.

Phone06 59 90 51 91 Emailcontact@sirianni-travaux.fr

Address113 Allée des Cigales, 06700 Saint-Laurent-du-Var