The process of opening a building’s shell starts with “scrim tape“, which keeps out water and wind on the outside edge of the framing (the flat surfaces that support the roof panels). It also protects the framing from being scratched as it is placed. This process can be complex, but it consists of just two steps: 1) seal the framing and 2) tape the joints.
The first step is to seal the framing with a tough tape. The second step is to cover the joints with plastic sheets, which are more resistant to water penetration than the usual masking tape (5–7-year rating). The plastic sheet should overlap one “tile” worth of space, which extends about thirty centimeters (one foot).
The roofing panels are fastened to the framing with a bead of “plaster” (waterproof material) on the edge of each panel. The plaster is further secured with a few layers of tape. It’s important to remove as much water as possible before installing the plaster and paper (polyvinyl acetate), because plastic sheets cannot be used indoors. They should not be used in areas where there will be heavy precipitation or where snow can enter through cracks, because they have very poor insulating capabilities.
Immediately after the plaster dries, the joints (unfinished edges) are covered with paper. The purpose of this step is to prevent water from entering. This step is especially important in areas that have a high level of humidity or precipitation, because if the joints are left uncovered, rain and snow will make it inside the building and damage the construction materials.
The panels should overlap by 30cm (one foot), which effectively prevents leakage. This overlap also prevents rain from entering through the gaps (when there is precipitation). During the final stages of construction, it is necessary to hammer the joints to remove air and make it airtight. Plastic sheets are only one-way tape; they allow water vapor to pass through them. Therefore, they require another type of sealant along the joints.
It is important that a building’s framework be covered by plastic as soon as possible, because materials used in construction tend to absorb water. Therefore, after a building is finished, the framework should be covered with plastic sheets. This process can be completed in a few days by laying down plastic sheets on the framework and covering the joints with tape.
The aim of this project was to build a house from a simple truck shell that was uninsulated. The material used to insulate the walls and roofing tiles were insulation batts composed of fiberglass and paper.
The house is 20 feet (6m) by 12 feet (3m). This is a standard size for this type of structure. 20 feet (6m) is the width of the truck shell. 12 feet (3m) is the depth of the truck shell. The walls are 2 feet (0.5m) thick and contain two layers of insulation batts and one layer of plastic sheets. The roof was insulated with 3 inches (8cm) of insulation batts and 6 inches (15cm) of plastic sheets. The insulation sheets were attached with the adhesive used in the batts. The plastic sheets were applied after the batts were fully cured. A metal tape was also applied to cover any gaps in the walls and roof, mainly from rainwater. The walls have cladding on all sides to prevent rain from getting into the house.
The frame of a truck shell is made with steel studs and metal joists, which contain eight inches (20cm) of foam insulation between them.