Opening or demolishing a load-bearing wall: a project to plan step by step!
There are many and varied reasons for demolishing or opening a load-bearing wall. You may want the work either to create space in a specific room of the house by enlarging it, or to make changes by adding a partition or an opening. The idea is to make the room fully functional and adapt it to the needs of the people living in the house.
Opening a load-bearing wall is a rather delicate project that calls for a professional's expertise. Their skills are needed to make sure the work goes ahead in excellent conditions and that safety and site clean-up are properly taken care of. A project to demolish a load-bearing wall therefore comes with a set of essential rules and principles to guarantee a successful job. Indeed, with poorly planned demolition or a wrong choice of the support meant to carry the part above the demolished section, an accident can happen quickly.
What is a load-bearing wall for?
Before any project to knock down a load-bearing wall, a few reminders are needed about the role and purpose of this element in the home. In any building, the load-bearing wall, as its name suggests, is there to carry the structure of the house, from the ground up to the roof framing. It plays a real role in supporting the overall architecture of the house. The load-bearing wall reinforces the stability and durability of the whole structure. It is a true foundation for the home. That is why materials such as concrete, brick, concrete blocks, stone and even timber are used to build load-bearing walls in the house. To ensure their strength and let them bear the various loads of the home, the walls must on average be 15 cm thick and blend harmoniously into the architecture of the house. They can be built outside as well as inside the house.
What are the characteristics of a load-bearing wall?
Not all the walls in a home are load-bearing. Otherwise, how can you tell them apart from the other walls in the house? To identify load-bearing walls, careful observation and a few simple checks will let you verify it.
- Does the wall make a sound or noise? By tapping a few times on a load-bearing wall, you will hear a deep or dull sound. In some cases, the sound may be hollow if the wall was covered with plaster when the building was constructed.
- Does the wall support a specific part of the house (roof framing, floor…) or is it simply an outer façade wall of the building?
- How thick can a wall be? As mentioned above, a load-bearing wall is on average 15 cm thick. If, after checking, the wall has these characteristics, there is no doubt that it is a load-bearing wall.
- What is the plan of your house? On this key construction document, it is easy to tell a load-bearing wall from a dividing wall or a façade wall. On the construction plan, the load-bearing wall is shown with a thick line to distinguish it from ordinary partitions.
Opening or demolishing a load-bearing wall: what permissions do you need before starting work?
Demolishing or opening a load-bearing wall requires certain authorisations. This is a legal obligation, because this work affects the structure of the home. The authorisations you need vary depending on whether it is an apartment or a detached house.
Opening a load-bearing wall in an apartment
In a co-owned building, to open or break through a load-bearing wall, the project must be approved by the co-owners' general meeting. To make sure of this, the structural engineer's report and execution plan (BET), the ten-year insurance certificate, the quote from the company carrying out the work, and the drawings from the technician in charge of the work must all be sent to the co-owners' general meeting beforehand.
For the work to be discussed, you have two options: either put your project on the agenda of the ordinary annual meeting, or ask for a meeting to be called so the matter can be discussed quickly and the project approved if appropriate. In most cases, the second option is charged for by the property managers.
Opening a load-bearing wall in a single-family home
In this particular case, the work to open the load-bearing wall must be declared to the planning department of the municipality where you live, together with calculations carried out by qualified professionals, which must be accepted. It should be noted that this declaration is not mandatory if the work is not intended to alter the facade of the house. Indeed, creating or closing an opening, or fitting a bay window, changes the exterior of the home because of its aesthetic impact, which is why this type of work must be declared.
When demolishing a party wall
Between two dwellings, whether an apartment or a house, it is necessary to have a joint condition survey drawn up by a bailiff (huissier). Their assessment is essential to evaluate any existing damage before work starts, so as to avoid disputes with neighbors over repairing damage that occurred well before the demolition of a shared load-bearing wall.
Hiring professionals for your project is essential!
Opening or demolishing a wall is heavy work, sometimes demanding, and requires proven technical skills. It is essential to check that the company has the experience and expertise needed to carry out the work properly. Always ask whether the company holds valid ten-year insurance or warranty. Opening or demolishing a load-bearing wall follows very specific steps, which fall to the BET, the architect and the occupant or owner of the house alike.
The role of the occupant or owner of the house
As the person for whom the work is done, they must call on a qualified architect and a BET.
The architect's tasks
The architect checks and assesses the plan to open a load-bearing wall and its consequences for the overall structure of the house. They make sure that the total or partial demolition of the wall comes with a replacement support structure.
Calling on a BET.
Their expertise is needed to choose the technique for opening or partially or fully demolishing the load-bearing wall. Taking the structural calculations into account, the BET will determine with great precision the type of elements that will support the opened wall.
The role of the company carrying out the work itself.
Once the BET has recommended the technique to use, it is up to our company to take care of the work on site.
The step-by-step process for opening a load-bearing wall.
The contractor chosen by the owner or occupant of the house to carry out the work is responsible for the smooth running of the site. Two essential principles must underpin its work: safety and site cleanliness.
In addition, the company first places props to temporarily support a lintel or the wall. This keeps the floor stable throughout the work. The company must also make sure the floor covering is properly protected with wedges during the job.
Next, it installs a steel lintel, an IPN, to support the upper parts of the house above the opened wall. The steel structure must be firmly anchored in the walls to ensure the stability of the whole. This steel strengthening is reinforced by sealing the beam with chemical anchoring or mortar.
Finally, the load-bearing wall can be cut through. This must be done methodically, generally starting from the top and working down, and progressively, making sure the lintel remains stable.
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