Each construction site is different, no two are alike. So it doesn't make sense to have a standard model applicable to all of them. The cleaning service at a construction site can be translated into what elementary activities? For example, cleaning meeting spaces, cleaning bathrooms, ... Does it make sense to develop a standard library of elementary activities - which describes the service, the type of equipment that can be used, the type of materials and people, the type of specifications that must be established in each case. Then, for each specific construction site, the site is visited, the client's requirements are listed, and a proposal is prepared taking into account the dimension, the set of elementary activities, their frequency, and specifications.
Does this make sense to you?
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