Read Article A concept rendering by Bild Architecture for a nine-unit apartment house at 186-198 Blake St. in Lewiston by Raise-Op. Under a new proposal, Raise-Op is looking to build a similar building on a vacant parcel at Walnut and Howe streets. LEWISTON — The nonprofit housing cooperative Raise-Op is hoping to expand its footprint in the downtown by doubling the size of its previously proposed housing development in the Tree Streets neighborhood. The City Council this week approved an updated option agreement with Raise-Op that will allow the organization to purchase additional vacant parcels downtown. Raise-Op is looking to build two, nine-unit buildings, which would boost the housing cooperative’s inventory from 15 units to 33.