Summary

– Active cracks

– Inert cracks

– Treatment of active and inert cracks

Cracks on facades are common pathologies. Before treating them, it must be determined whether the crack is active or inert. In the case of an active or inactive isolated crack, the crack can be treated as a joint and filled with flexible mastic. The treatment of cracks like the treatment of facade joints is a step in the preparatory work.

Active cracks

These are the cracks that continue to evolve. They are not stabilized. They are generally found at the building’s singular points, but they can be distributed over the entire facade. With relevant facade audits, active cracks greater than 0.2 mm, especially at masonry junctions, can be transformed into a flexible joint (expansion joint):

– Use an elastomeric mastic to fill the crack.

– This joint can be covered or not.

The main singular points of a building

Name	Location/definition
Acroterions	These elements are located above the roof/terrace. They form the edge of walls or railings.
Linking/pulling	Metal reinforcement intended to stiffen horizontally or vertically a wall, a slab in a wall made of bricks, concrete blocks, stones… They prevent the building from dissociating.
Masonry joints	The boundary separating two distinct masonry zones.
Chimney stumps	Or “roof outlet”: the chimney flue outlet at the roof level.
Balconies, railings	Platform at floor height and projecting from the facade, equipped with a guardrail to protect people.
Caps	It is the part protecting a bay, a small cover in overhang.
Streamers	It is a protruding strip on the facade usually at the floor level division of the floors.
Lightens	The lightens are the facade elements between the floor level and the sill of an opening (window, door, skylight, etc.).
Window (bay) sills	It is a masonry or prefabricated piece located in the lower part of the window.

Inert cracks

These are the stabilized cracks that no longer evolve.

Cracking and microcracks up to 0.2 mm can be left as they are. The associated coating is class I1.

Cracks up to 0.5 mm can be left as is; the associated coating is class I2.

Treatment of active and inert cracks

Treatment of active and inert cracks

Whatever the treatment, it must be:

– adapted to the type of material;

– adapted to the size and types of cracks;

– compatible with the coating.

Note: Follow the instructions for using the products and do not forget the usual safety precautions.

Table of treatment of active and inert cracks

	Active cracks	Inert cracks > 0.5 mm
Treatments	– Brush and scrape cracks to remove dirt and loose parts. – Open the crack with the triangle. – Brush the open crack. – Fill with putty. – Allow to dry and re-fill if shrinkage occurs. – It is possible to place a framework/calicot/gallon locally over the cracks, especially at single points. – This calico is embedded in the veneer. – Application of a suitable Class I4 coating.	– Brush the surface to remove dirt and powdery materials. – Open the “V” crack with a triangle. – The opening of the crack allows for good adhesion of the filler later on. – Brush the opening and the bottom of the crack. – You can apply a fixative in the crack before the repair filler. – Fill the crack with a soft exterior sealant. – If necessary, cover with a facade covering adapted to the characteristics of the cracks.

If you wish, you can get in touch with a specialist in facade restoration. They will be able to propose an estimate, be it for Facade Audits, Rope Access, Anchor Point Services, Rope Access Painting, and Cladding Auditing.