  After primordial inflation, the universe may have experienced a prolonged
reheating epoch, potentially leading to a phase of matter domination supported
by the oscillating inflaton field. During such an epoch, perturbations in the
inflaton virialize upon reentering the cosmological horizon, forming inflaton
structures. If the primordial overdensities are sufficiently large, these
structures collapse to form primordial black holes (PBHs). To occur at a
significant rate, this process requires an enhanced primordial power spectrum
(PPS) at small scales. The enhancement of the PPS, as well as the formation and
tidal interaction of the primordial structures, will in turn source a
stochastic gravitational wave background(SGWB) that could be detected by
current and/or future gravitational wave detectors. In this paper, we study the
SGWB arising from these different sources during slow-reheating, focusing on a
PPS that satisfies the requirements necessary for the formation of PBHs with a
mass of $M_{\rm PBH}\simeq 10^{21}$ and that constitute the entirety of dark
matter in the universe.
