To the real estate editor: In your Friday, Jan. 4, issue Charles E. Dole answered the question of Mrs. Havva Indriss of North Haledon, N.J., requesting information on what the most effective insulation for a cathedral roof should be and how it should be installed.
The November issue of Housing magazine pictured and described the house being built on Martha's Vineyard by Mark Shea. He used rigid phenolic foam insulating slabs, 3 3/4 inches thick, glued to the underside of the roof between the rafters. This is a new material; it is nonflammable and light and can be painted. It has an R factor of 5 per inch.
It is manufactured in Piscataway, N.J., by Lisi America Inc., 600 Prospect Avenue, which is not far from where Mrs. Indriss lives.
I would be glad to help Mrs. Indriss if she cared to call me at (201) 752- 1452. James Trotter Lisi America Inc. Piscataway, N.J.