Why not let contractors write the scope?
Because each one will write a different scope, and the lowest number will belong to the smallest scope. When the engineer writes the documents, the association compares price rather than guesswork.

Three bids on three different scopes are not a bid comparison. Construction documents make the numbers mean the same thing.
Over the course of a contract, maintenance projects large and small will be required to keep a building properly maintained. When that happens we provide document development and a pre-bid meeting at no charge to the association, on the condition that we are engaged to perform the Contract Administration for the project.
Document development includes a detailed scope of work, technical specifications, and construction drawings that convey the work and the details accurately to the contractors bidding it.
We tabulate the bids and give the association a breakdown of project costs from each contractor, compared line for line because every contractor priced the same document.
We will also scan the original existing building plans and return them to you with an electronic copy, so the association holds a digital record set.
Through the project we act as the liaison between the association and the contractor. The level of our involvement is set by what the association needs.
Because each one will write a different scope, and the lowest number will belong to the smallest scope. When the engineer writes the documents, the association compares price rather than guesswork.
Document development and the pre-bid meeting are provided at no charge to the association where we are engaged to perform the Contract Administration for that project.
Send the building, the site, and the timeline. A licensed engineer will tell you what we would actually do.