Summary: more money became available after the original plans were drawn up.
The library in question is officially the Hanover Town Library but everyone calls it the Etna Library. (Etna being the part of Hanover in which the library is located.)
According to the annual library reports summarized at the Etna Library web site, there was a change of plan.
In the 1904 report:
"The plan for the library building has been accepted by the trustees and materials are being purchased with the intention of having the building completed and ready by September 1, 1904." - Horace F. Hoyt, Library Treasurer
but then the 1905 report describes a potential change of plan:
"To the inhabitants of the Town of Hanover, in the County of Grafton, in said State, qualified to vote in Town affairs: To see if the town will vote to raise a sum not exceeding six hundred dollars (in addition to the present building fund) for the purpose of enabling the trustees of the Hanover Public Library to erect a brick library building."
The results are given in the 1906 report:
Library highlights: "After the vote of the town to build with brick there was $2,100 available, with interest accrued. In such a case an architect's fee and a contractor's profit would have taken too large a share of the amount; hence the trustees themselves made the plans and bought the materials and superintended the work. The best materials were procured, the workmanship is first-class throughout, and it is believed that there will be little or no need of repairs for years to come. The underpinning, although it has a three-inch cut chamfer, was secured at the price of plain stone, as it was originally cut for a building elsewhere. The brick was from an extra good lot at the Lebanon yard, and was laid by very competent masons. Cement was used to strengthen the mortar. The roof is covered with slate and copper, materials the most durable to be had for the purpose. The plaster, made from lime putty which had seasoned several weeks, was hardened by admixture with cement. The interior is 25 ft. by 33 ft., in one room, finished in hazelwood throughout and varnished. This includes the window casings, the vestibule and door, the shelving which extends entirely around the room, and a paneled ceiling overhead." ...
(The 1906 report gives more details.)
These paragraphs are excerpted from the Hanover annual reports (copies are viewable at https://scholars.unh.edu/hanover_nh_reports/). These reports record the outcome of the votes taken at the previous year's meeting, so the approval of the extra expense for brick construction occurred at the 14 March 1905 Hanover Town Meeting, as recorded on page 42 of the 1906 report.
Added 12 July 2024. The undated Early Handwritten Note About the Library's Architecture on the historic documents page of the library's web site (navigate: About >> History >> Historic Documents) seems to have been written after the decision to build was made and before the building materials were chosen. It has paragraphs labeled "In case of brick building" and "For the wooden building...". It refers to three sheets of drawings, and contains phrases like "as per drawing". This seems consistent with the building material choice being been based on "can we afford it" financial considerations.
