Laminated panels are made in a process whereby a starting foam formulation is processed through a mixhead, passed through a branched distribution system and dispensed through multiple outlets of the distribution system to produce a foam layer on a bottom facing layer. The foam layer is monitored for the presence of surface bubbles. When surface bubbles are observed, the backpressure in the mixhead is increased to reduce or eliminate the surface bubbles. An apparatus for performing the process includes an adjustment means at or upstream of a first branch point in the distribution system to increase or decrease the backpressure in the mixhead.