I Recently purchased a new home from another builder... go figure. Any way, Pex tubing was used for hydronic baseboard heating runs. Fiberglass insulation with kraft paper was placed beneith the the pex tubing between floor joists (basement ceiling), not split around (the tubing). I was looking for plumbing mistakes (extreamly noisy plumbing), and noticed that the heat from the tubing caused the tar (which bonds fiberglass to the paper), to migrated to the surface of the kraft paper. I'm worried that the tar will eventually eat through the pex and cause it to fail. I've surched for answers on this and have come up empty handed. Common sense, tells me this could be a problem. Any comments would be helpful.