Before embarking on any painting work, it is essential to fill in any potential cracks that may have appeared on your walls. How to proceed?
Have you seen a small crack appear on your wall? Don't neglect repairing these small imperfections which can quickly become big! The good news, you don't need to have a master's degree in DIY to overcome cracks. To find the most suitable remedy, it will be necessary to define the type of crack but also the type of wall on which to carry out the repair. Let's take stock of the best way to repair cracks in a wall.
WHAT TYPE OF CRACK ARE YOU DEALING WITH?
First of all, it is important to observe your crack to define its severity and the solution to put in place:- Microcracks: generally superficial, they measure less than 0.2 mm. They are most often linked to the quality of the mortar used for masonry joints or the consequence of a humidity problem. These microcracks are easy to repair with a filler.
- Medium cracks: larger than microcracks, they measure less than 2 mm. Before repairing these cracks, their stability must be observed using a crack tester. If the crack does not improve, you can repair it with filler. However, we recommend 'bridging' the crack with a calico to prevent it from reappearing. Conversely, if the crack develops, you must quickly find the cause and call a masonry company.
- Large crack-type cracks: they are more than 2 mm and sometimes up to 20 cm. They should not be taken lightly because they are most often due to faulty construction of the building or movements of the ground. These cracks can be dangerous, call a specialized company as soon as possible.
HOW DO YOU REPAIR A CRACK ON A PLASTER INTERIOR WALL?
The necessary equipment:
- A triangular scraper,
- Filler (tube, pot or powder),
- A painter's knife,
- A large knife to coat,
- A brush,
- A sponge,
- A roll of calico,
- A sheet of abrasive.
The steps:
- With the tip of the scraper, open the crack. Dig it slightly so that it opens in a V. Remove all the parts and particles ready to come loose.
- Clean the wall using a paintbrush (or a shop vacuum if you have one).
- With your sponge, you can then moisten the edges of the crack: the coating will stick better!
- With your painter's knife, apply the filler perpendicular to the direction of the crack. Make it penetrate well.
- Smooth the coating with a wide knife.
- If your crack is medium and to prevent it from opening again, you can reinforce your filling with calico (which is nothing other than a strip of reinforced fabric). To do this, cut a strip of calico the length of the crack and place it on the still-fresh plaster. Add a new layer of coating on top of the calico.
- Leave to dry for 24 hours then sand lightly to remove any irregularities on your wall.
- Apply a smoothing coating which you will sand once it has hardened.
- Paint.
HOW DO YOU FILL A CRACK IN A CONCRETE WALL?
The necessary equipment:- A perforator,
- A wire brush,
- An anti-rust product,
- Cement,
- Sand,
- Water
- A brush,
- A trowel,
- A polystyrene float.
- Use the hole punch to make a groove in the wall at the crack.
- If your wall is made of reinforced concrete, dig up to the frame and then with the wire brush, remove any potential rust present on the frame.
- Once the rust is removed, dust and apply a rust remover with a brush. Let dry.
- Prepare your repair mortar: to do this, mix cement, sand and water.
- Moisten the area to be filled (a good way to make it easier to hang the mortar) then fill in the groove made in the wall with a trowel and the mortar.
- Smooth the mortar with a polystyrene trowel to level the surface and let dry.