It all depends on the wall construction. Timber frames can have conventionally framed 2x walls or SIP (structural insulated panel) walls. If the walls are made up of normal 2x4 or 2x6 studs, insulation can be installed or replaced in between the studs. If the walls are SIP's the insulation is already there.
To see a typical timber frame SIP wall configuration, see the link below.
Thoracic cavity
pelvic cavity
A cavity that houses body organs is called a body cavity. The main body cavities are the thoracic cavity, abdominal cavity, and pelvic cavity, which contain organs such as the heart, lungs, stomach, and intestines.
houses can be insulated in many different ways, roof insulation can be installed into attic space, you can get cavity wall insulation, double glasing on the windows, draft excluders on the bottom of doorways, all of these help to keep the heat within the house and to prevent it from being lost to the oustide environment. Walls can be insulated externally with the use of an External Wall Insulation system, full details found in "The Complete Guide to External Wall Insulation" currently available via Ebay
chest
The dorsal cavity houses the brain and spinal cord.
The dorsal body cavity contains the cranial cavity (which houses the brain) and the vertebral cavity (which houses the spinal cord). These cavities are protected by the bones of the skull and vertebral column.
The spleen is located in the abdominal cavity.
wigwams
wigwams
The cranial cavity and vertebral cavity reside within the dorsal body cavity, which is the larger cavity that houses the brain, spinal cord, and related structures.
It houses the ribs and chest muscles