It is proved first in this paper that all weakly $\kappa\overline{\theta}$-refinable spaces which were defined recently in [4] are irreducible for any infinite cardinal $\kappa$, i.e. any open cover of such spaces has a minimal open refinement. The special case $\kappa =\aleph _0$ has been proved before by J.C.Smith. A generalization of weakly $\kappa\overline{\theta}$-refinable and weakly $\overline{\delta\theta}$-refinable spaces is defined as weakly $\overline{\delta _{\kappa}\theta}$- refinable and it is proved for $\kappa =\aleph _{\alpha}$ that any $\aleph _{\alpha +1}$-compact, weakly $\overline{\delta _{\kappa}\theta}$-refinable space has the Lindel\"of number $\le \aleph _{\alpha }$. Thus it is shown as a corollary that a regular, perfect, $\aleph _1$-compact $T_1$ space is hereditarily paracompact if it is weakly $\delta\theta$-refinable.