S-IMPLER BIM Protocol: Guidelines for using Building Information Modelling in the Retrofit of Social Housing

In 2010, the UK government made a significant commitment to upgrade the energy efficiency of 7.0 million British homes by 2020 aimed at reducing carbon emissions by 29% to address fuel poverty. Statistics suggest that the number of households faced with fuel poverty in 2014 reached 2.38 million in England . The NIHCS survey, in 2011, indicates that over 40% of households were fuel poor in Northern Ireland. The targets are becoming increasingly challenging, at a national level, for reducing fuel poverty and the national carbon footprint. The carbon reduction target for the UK nationally is 80% by 2050, the UK Government has committed to support insulation for up to 1.5 million solid wall homes.

The Solid Wall Innovative Insulation and Monitoring Processes using Lean Energy Efficient Retrofit - S-IMPLER aims to develop a solution to the insulation of solid walls in the UK to achieve up to a 60% reduction in monitored energy costs, with less disruption, at least 10% faster, without reductions in quality and safety. The project is a joint activity, developed by a consortium including a housing association – NIHE (Northern Ireland Housing Executive), a contractor – Carillion, three companies, i.e., Tensor, VRM and Collaborative Improvement Ltd; two academic institutions, i.e. Leeds Beckett University and University of Huddersfield; and a construction research organisation – BRE (Building Research Establishment).

This report presents the BIM protocol, which demonstrates the workflow of BIM-enabled analyses for alternative retrofit scenarios to simulate energy efficiency, 4D BIM for planning and reduced users’ disruption, and cost analysis. In addition, the results of the analysis developed as part of the S-IMPLER NIHE social houses retrofit are presented, providing examples of how to implement the protocol in future retrofit projects.

A retrofit coordinator with BIM knowledge would be able to follow the detailed guidelines as well as the examples in this protocol to execute the whole process on behalf of the Client (housing association or social housing provider). Even though the S-IMPLER project has focused on ‘no-fine’ solid walled houses, the protocol is applicable to evaluate alternative retrofit solutions of any type of solid walled homes.

Figure 1 presents an overview of the protocol. The Client possesses information of its existing solid walled housing stock. It needs to identify existing performance issues, as well as establish the target performance outputs expected from the retrofit in terms of energy consumption, costs, time and users’ disruption. The BIM coordinator will use the data, as well as drawings, measurements of the existing houses or 3D scanning information to perform the BIM-enabled what-if analysis for retrofit scenarios, presented in Sections 3, 4, 5 and 6.

Following the BIM based simulations and analysis, the client will be able to select the most suitable retrofit solution(or scenario), based on data presented in a what-if scenario matrix (see session 6). The selected solution can then be utilised to support engagement with the supply chain and tendering for the retrofit construction works.

During the construction phase, the BIM coordinator can support the contractor to review the 4D simulation and implement an adapted version of the Last Planner System® of Production Planning and Control on site. After the retrofit process is finished and the house is in use, the performance of the retrofitted house can be evaluated using Tensor’s Home Energy Monitor Tool (see details at http://www.heatingsave.co.uk/). Finally, for the cases in which the Clients decide to collect monitoring data and have other similar housing which needs retrofitting, the data from the house energy monitoring could be used to calibrate further energy simulations for similar housing schemes.