Method for fitting an edging strip, without using screws, as a wall edging element for flooring or for a ceiling covering, comprising the steps of: • providing at least one edging strip retainer - having a base leg designed and intended to rest on the substrate and to engage under the flooring or ceiling cladding when the edging strip is fitted, - having a wall leg which is integrally connected to the base leg, and - having an engagement portion which is designed and intended to engage with the edging strip so as to retain it when said strip is fitted, • engaging the edging strip with the engagement portion of the edging strip retainer, characterised in that the base leg and at least a portion of the edging strip retainer adjoining the base leg have a width (b) which is smaller than a predetermined spacing between the flooring or ceiling cladding and the wall, and in that, between the step of providing the at least one edging strip retainer and the step of engaging the edging strip with the engagement portion of the edging strip retainer, the method further comprises the steps of: • inserting the at least one edging strip retainer into the expansion joint, which has the same width as the predetermined spacing, between the flooring or ceiling cladding and the wall, and specifically in such an orientation that the base leg is arranged so as to extend substantially in parallel with the substrate, the longitudinal extent of the base leg extending substantially in parallel with the outer edge of an adjacent portion of the flooring or ceiling cladding, until the base leg of the at least one edging strip retainer is resting on the substrate, and • rotating the edging strip retainer about a substantially vertical axis until the base leg engages under the flooring or ceiling cladding and extends so as to be substantially orthogonal to the wall. • providing at least one edging strip retainer - having a base leg designed and intended to rest on the substrate and to engage under the flooring or ceiling cladding when the edging strip is fitted, - having a wall leg which is integrally connected to the base leg, and - having an engagement portion which is designed and intended to engage with the edging strip so as to retain it when said strip is fitted, - having a base leg designed and intended to rest on the substrate and to engage under the flooring or ceiling cladding when the edging strip is fitted, - having a wall leg which is integrally connected to the base leg, and - having an engagement portion which is designed and intended to engage with the edging strip so as to retain it when said strip is fitted, • engaging the edging strip with the engagement portion of the edging strip retainer, characterised in that the base leg and at least a portion of the edging strip retainer adjoining the base leg have a width (b) which is smaller than a predetermined spacing between the flooring or ceiling cladding and the wall, and in that, between the step of providing the at least one edging strip retainer and the step of engaging the edging strip with the engagement portion of the edging strip retainer, the method further comprises the steps of: • inserting the at least one edging strip retainer into the expansion joint, which has the same width as the predetermined spacing, between the flooring or ceiling cladding and the wall, and specifically in such an orientation that the base leg is arranged so as to extend substantially in parallel with the substrate, the longitudinal extent of the base leg extending substantially in parallel with the outer edge of an adjacent portion of the flooring or ceiling cladding, until the base leg of the at least one edging strip retainer is resting on the substrate, and • rotating the edging strip retainer about a substantially vertical axis until the base leg engages under the flooring or ceiling cladding and extends so as to be substantially orthogonal to the wall. • inserting the at least one edging strip retainer into the expansion joint, which has the same width as the predetermined spacing, between the flooring or ceiling cladding and the wall, and specifically in such an orientation that the base leg is arranged so as to extend substantially in parallel with the substrate, the longitudinal extent of the base leg extending substantially in parallel with the outer edge of an adjacent portion of the flooring or ceiling cladding, until the base leg of the at least one edging strip retainer is resting on the substrate, and • rotating the edging strip retainer about a substantially vertical axis until the base leg engages under the flooring or ceiling cladding and extends so as to be substantially orthogonal to the wall.