Final answer:
Thermal insulation in a low-slope roof can be installed in three positions: on top of the roof deck but beneath the weatherproofing layer, known as a conventional insulation system; directly on top of the weatherproofing layer, called a protected membrane roof; or between two layers of the roof structure, often referred to as a composite insulation system.
Step-by-step explanation:
The three positions where thermal insulation can be installed in a low-slope roof are as follows:
- On top of the roof deck but beneath the weatherproofing layer; this setup is often referred to as the conventional insulation system or compact roof.
- Directly on top of the weatherproofing layer, which is then protected with an overlying layer of gravel or paving, this type of installation is known as a protected membrane roof (PMR) or inverted roof.
- Between two layers of the roof structure, this is sometimes called a sandwich or composite insulation system, where insulation is placed in between two layers of roof deck or between the deck and a built-up waterproof layer.
These installation methods aim to reduce heat loss or gain through the roof, improving the energy efficiency of the building.