A storage stable isocyanate-reactive composition includes a reactive component including (a) 5 wt % to 30 wt % of at least one Novolac-type polyoxypropylene polyether polyol having a hydroxyl functionality from 2 to 5 and a hydroxyl number from 130 to 450 mg KOH/g, (b) 20 wt % to 60 wt % of at least one high functional polyether polyol having a hydroxyl functionality from 6 to 8 and a hydroxyl number from 300 to 700 mg KOH/g, (c) 2 wt % to 30 wt % of at least one low functional polyether polyol having a hydroxyl functionality from 2 to 5 and a hydroxyl number from 50 to 400 mg KOH/g, (d) 2 wt % to 30 wt % of at least one amine initiated polyol having a hydroxyl number from 250 to 600 mg KOH/g, and (e) 1 wt % to 25 wt % of one or more additives; and a hydrocarbon physical blowing agent component in an amount of at least 10 parts by weight for each 100 parts by weight of the reactive component.