Conversion of a 40ft Shipping Container into an Emergency Home Unit
Categories: Building Methods
Ceardean Architects where delighted to lead the Ripple Team to achieve the conversion of a 40ft Shipping Container into a Emergency Home Unit for SVDP in 3 days at the Irish Museum of Modern Art in November 2014.
The Ripple project is a container fully fitted out as a home with two bedrooms, bathroom, plumbing, kitchen and electrical appliances. The objective of the project was to provide an emergency housing unit for Saint Vincent de Paul, and the aim was to do this using an alternative building system. Every aspect of the project was designed to require minimal specialist input and to facilitate a selfbuilder that does not have a very high level of skill. The project took one week to build and brought together over 60 contractors who donated their time, expertise and labour. The container and all materials used within were donated by suppliers and those involved. The Ripple project was exhibited in IMMA for a month and has now been donated to St Vincent de Paul and moved to Longford for use as a refuge for families.
Key considerations Shipping containers range from 20-, 30-, 40- to 45-foot in length. 20- and 40-foot containers are easier and cheaper to source than 30- and 45-foot containers. The following considerations need to be taken into account: -Proper planning permission must be obtained if you plan to use the container as a separate dwelling unit in your particular region or country. -The container will typically require a waste water treatment system, percolation area and soakway, or a connection to foul and surface drainage area. -The container must be either internally or externally insulated. -The container will need an appropriate foundation designed by a structural engineer. -Consideration must be given to how the container will be connected to utilities (water, electricity and gas) prior to the commencement of the project.
Design The design brief for the project was the conversion of a used shipping container into fully functional compact residential unit that would house a small family on a temporary basis. The internal spatial arrangement of the container was designed to provide accommodation for a family of 3-4 people, with a bedroom space, cooking and sanitary facilities, and a living space. The design criteria included the additional burden of needing to meet all of the relevant regulations for a semi-public building, as the space would be used by different people and not used continuously by one family and therefore could not be considered a private building. The circulation space of the design had to be in compliance with current access and fire safety regulations. The design also required the consideration that the container would be lifted when complete and moved to its final destination. This therefore placed restrictions on the fenestration openings that could be made in the container and added the requirement for structural strengthening of the container.
PREPARATION & STEELWORKS
Checking the container It is crucial to verify that the container is clean from contaminants and has not been used to transport chemicals. The plywood floor must be checked for wetrot and the steel base plate of the container checked for rust as it can often rust heavily. Ensure that the container is watertight.
Siting and foundations It is crucial that the container is lifted well off the ground. A compacted hardcore base or a concrete pad designed especially to suit the container may be used as its foundation. When designing the foundation, care needs to be taken to minimize thermal bridging. This can be achieved by placing a rubber thermal isolation plate on top of the foundation.
Main openings Cutting a container’s wall alters its structural integrity, so an alternative structure would need to be provided, especially if the container will be moved. Hence it was decided to cut only one opening in the Ripple container. The opening was reinforced using a vierendeel truss and a steel plate was inserted around all four edges of the opening. This plate was necessary to hold the frame of the combined sliding door and window element in place.
Wall Build Up
Vapour control membrane A vapour control membrane was taped to the exterior of the container, in order to achieve an air-tightness value closer to passive standard. Ensure that the membrane wrap is continuous, especially around the doors and corners.
Fixing the timber frame The base detail of the timber frame is a crucial part of the project. A steel plate was welded onto the metal base of the container. This plate supports a timber soleplate and portal frames made from timber studs, which were fixed at regular intervals. These portal frames form the main structure, which is independent from the walls of the container. This removed the need for fixings to be made through the container’s steel walls and the vapour control membrane, as any holes would have decreased the container’s air-tightness. Steel angles were welded to the container wall at regular intervals to brace the timber frame, in order to avoid lateral shearing.
Insulation it is important that the fabric of the wall is designed to avoid condensation and wetrot. A warm wall construction was chosen because the alternative of using internal insulation increases the risk of condensation and rot, as well as reducing the interior size of the container. Kingspan high-density insulation was used in the Ripple project, and Kingspan was contacted to design wall insulation for the container that would avoid condensation. 1/3 insulation was used for the interior layer and 2/3 insulation for the second layer. The first layer of insulation was fixed between the timber battens, with the second layer fixed on top, and screws driven through to fix the insulation panels in place. The screws used were Irish Wire’s SPAX screws, specified especially for the wall, where screws at regular intervals were fixed at an angle in order to prevent shearing.
Weathering membrane A weathering membrane was taped securely to the Kingspan insulation panels. Infiltrations for the ventilation ducts were cut in the membrane and insulation layers and sealed afterwards.
Fitting the frame of the sliding door Structurally, a post could have been put in the middle of the opening cut in the container, which would have been a better option, but because of the tight construction programme, a design decision was taken to have one main window element consisting of window panels and sliding door as this would decrease the risk of the pre-ordered door panel not fitting. In this design, the steel angle that would stabilise the doorframe needed to be placed on the exterior, not the interior of the construction as is typical. Different systems typically have different baseplates and it was important to the Ripple team that the final interior finish of the container would be on a similar level to the frame of the sliding door, in order to have level access to the container. Below the doorframe was finished with fibreglass as a weather proofing.