We have just bought a house with cathedral ceilings and a hot tar roof that needs replacement. What would be the most effective insulation, how should it be installed, and what color roof would promote greater energy savings? Mrs. Havva S. Indriss North Haledon, New Jersey
Perhaps the easiest way to insulate the cathedral ceilings is to lay insulation board over the stripped-down roof deck, add a layer of plywood, and follow with the new roofing. You have to replace the hot-tar roof anyway. If you wish, you can add two-inch-thick insulation material to the roof, thus achieving up to an R-10 value.
Of course, you could blow cellulose or foam insulation between the rafters, assuming that the beams are not exposed. But be advised that both cellulose and ureaformaldehyde insulation have come under severe attack because of the large number of shoddy installers now on the road.
Massachusetts, in fact, has become the first state to ban the use of ureaformaldehyde insulation in homes and a court suit may result.
Should you opt for this course, make absolutely sure of the company with which you deal, check its references thoroughly, and talk with former customers and see what they have to say. Don't be rash in signing a contract for anything.
Technically, it will probably be easier and less expensive to work from the outside.