A method for the manufacture of polyisocyanurate foams which comprises blending a "B" side with an "A" side comprising an isocyanate. The "B" side comprises a diol, an amine/quaternary ammonium borate ester blend, a surfactant, a blowing agent, and a catalyst which is present in amounts up to about 20% of the total weight of the "B" side. The "B" side remains a homogeneous liquid for at least three days without the need for agitation and the foam formed by this method has a friability not exceeding 30%.