  In this work we investigate the moduli stabilisation problem and the
requirements for de Sitter vacua within the framework of type IIB string
theory. Using perturbative effects arising from the various sources such as
$\alpha^\prime$ corrections, logarithmic as well as KK and winding-type
string-loop corrections along with the higher derivative $F^4$-contributions,
we present a moduli stabilisation scheme in which the overall volume is
realised at exponentially large values such that $\langle {\cal V} \rangle
\simeq e^{a/g_s^2}$ in the weak coupling regime, where $a$ is a parameter given
as $a = \frac{\zeta[3]}{2 \zeta[2]} \simeq 0.365381$. We also present a
concrete global construction using a $K3$-fibred CY threefold with $h^{1,1} =3$
which shares many of its properties with those of the standard toroidal case,
and subsequently generates the appropriate corrections needed to fix all the
three K\"ahler moduli at the perturbative level. We further discuss whether de
Sitter vacua can be ensured through appropriate contributions of uplifting
terms in the effective potential.
