After the painting was completed we needed to start on the interior. The first job was to totally strip the interior removing all of the cabinets, partitions, wall panels, headliners, anything that could be removed except the factory wiring. When this process was completed there was only the aluminum frame and the body panels, we even removed the compartments for the Propane tank and generator as on the 23 these were wood and we felt that wood was not an appropriate material especially around the generator as a fire in the generator could quickly enter the coach through wood.
At this point it was easy to see just how bad the original insulation job had been done. The original insulation was spray foam and the builders were very careful to be sure that the foam did not expand above the ribs and make more work for them to cut back to that level. As a result the foam was marginal in thickness and never full height and in many places did not exist at all. To bring it up to what I considered adequate insulation I trimmed the existing the foam back either 1/2" below the surface of the ribs or 1" depending on how good the existing foam filled the area. This space was then filled in with layers of foil backed 1/2" urethane foam board to bring it up level with the ribs. Under the dash area I added a layer 1/2" closed cell foam in place of the felt type insulation that was there originally. Unfortunately there is no insulation in the floor of a 73. We considered putting down a layer of insulation on top of the floor and then a new floor over that ut this would reduce head room and being 6'5" the loss of head room was not desirable so it goes without any floor insulation.
In the area of the front and rear caps where there was no insulation I add two layers of the 1/2" Urethane foam board. By laying an angle iron on the ground with the sharp angle up it was possible to lay the foam board over the angle iron and gently apply pressure to crease it and by doing this multiple times it was possible to make the foam conform to curved surfaces.
The dash was removed and a closed cell foam was glued over all the surfaces replacing the felt like pad that was there.