Heaney’s poem opens with a first-person speaker describing the work of “[m]asons” (Line 1): workers who use stone for construction. The speaker relates how when masons start a new project, they are very “careful” (Line 2) while conducting the scaffolding—the temporary structure used in the construction of buildings. This task creates the extended metaphor of Heaney’s poem. The masons are meticulous “to test out the scaffolding” (Line 2) to insure it’s security prior to making use of it. Scaffolding also refers to support educators provide their students for moving from one level of knowledge to another.

The speaker details how masons inspect their scaffolding. Even though the subject is not explicitly stated in the second stanza, readers can infer that the masons are still the implied subject. The masons ensure that the “planks” (Line 3) of the scaffolding don’t “slip at busy points” (Line 3), meaning they check to make sure that the most traveled portions of the scaffolding are secure and stable so workers won’t fall while using the scaffolding. In addition to checking the planks, the masons double check that all “ladders” (Line 4) are “secure” (Line 4) and that all “joints” (Line 4), or locations where building elements meet, are “tighten[ed]” (Line 4).