The Town Hall Building Committee will meet Tuesday to open bids on a proposed $5.6 million renovation project for the building that will be on the May 9 Town Meeting warrant. Contractors were given an extra week to complete their bids on the project, after the original proposal was trimmed to cut costs. The committee met last week to find “nice to have” but expendable features that could be dropped, hoping to increase the chances for the overall plan’s approval. According to Town Manager Blythe Robinson, the process has included some unpleasant surprises. The brick facade has separated from the building and needs to be reattached, she said. A copper roof for one section of the building, wooden flooring for the ground floor, and storage cabinets and countertops have been scrapped from the proposal; details about the project have been posted on the town’s website, www.upton.ma.us . Robinson said Town Hall’s historic status made the option of selling it and building a new facility a much more expensive alternative. The Community Preservation Committee will discuss the project during a 7:30 p.m. meeting on May 1. As much as $5.1 million of the estimated cost may be eligible for community preservation funds. If voters approve the renovations, the municipal offices in Town Hall would move to Holy Angels Church for about a year while the work is completed.