Feasibility, Benefits and Challenges of Modular Homes in Ireland

Keywords: environmental impact, feasibility, housing, Ireland, modular.

Introduction

The residential construction sector in Ireland is an area that has experienced vast change in recent times, most notably in areas such as design, health and safety, banking regulations, planning processes and building regulations. Ireland in particular has also seen large swings in supply and demand, which has added to instability in the market.  In contrast, the actual construction sequence, has remained largely similar – most houses begin at the design stage, prepare the site, lay the foundations, build the structure, install the mechanical and electrical components and finish with the interior fit out.

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There have been some recent innovations such as fast tracking, whereby construction begins before the full design is completed. The foundations and structure are designed and construction begins with these while the rest of the design is finalised in tandem with the initial building phase (SOURCE). Also, poured concrete has become more popular in residential building, with benefits such as higher load bearing capacity walls, increased design versatility and reduced leakage (Spak et al. 2016). These approaches are still relatively new in the building trade and while they have been adopted in some cases, their use is far from widespread. They do have added benefits although they have not been sufficiently cost effective to replace traditional methods. As the market continues to evolve, modular construction may seem to address some of the issues currently facing developers. It allows for a shorter project timeframe, reduced cost and an increased flexibility in meeting the demands of an unstable market (Velamati, 2012)

Modular construction is a process which focuses on constructing as much as a structure off site as is economically viable. Individual components are constructed individually and the transported to site and assembled together into the finished structure. Many modular structures are built with the aim of leaving them permanently in the ‘one location for the duration of the useful life’ (Velamati, 2012: P9). The Modular Building Institute (2011) describe it as the use of prefabricated rooms rather than prefabricated mechanical systems, pods or walls. Modules are typically sixty to ninety percent constructed off site (depending on the project), and then assembled on site at the final stage.

Research aims and objectives

This research project will aim to assess the market for modular homes in Ireland. It hopes to discover if constructing this type of housing is both achievable and cost-effective while also assessing its advantages and disadvantages. With this in mind, these aims raise the following primary objectives:

To analyse modular construction and its feasibility for use in the Irish housing market.

To assess the key benefits of modular homes in Ireland.

To assess the key challenges to modular homes in Ireland.

To analyse the environmental benefits of modular construction.

To assess the profitability of constructing modular homes in Ireland.

The hypothesis which this research aims to investigate is ‘are modular housing developments both achievable and profitable in Ireland and if so, could they be used to ease the present shortage in the Irish housing market.’

background

With the upturn in the Irish economy over the past few years, the need for housing has witnessed a considerable surge in demand. In turn, property prices have increased by 42%. From their lowest point in 2012, house prices have risen by €93,000 from an average of €220,000 up to €313,000 in 2016 (Department of Housing, Planning and Local Government, 2016). In reaction to the inflated house prices of the Celtic Tiger and the subsequent property crash, the central bank introduced various measures to prevent a reoccurrence. Most notably, the amount an individual must save before they can obtain a mortgage has been increased, from 10% of the property value to 20% (for properties above €220,000) (Citizens Information, 2018). With all of this in mind, buying a house in Ireland has become more difficult. Furthermore, rental prices – particularly in Dublin – have increased significantly. The Residential Tenancies Board (2017) have reported a 41% increase in rent from 2012 to 2017.

With all of this in mind, rent prices have become a major societal issue. Rents nationally accounted for 22% of disposable income in the third quarter of 2017 (Department of Finance, 2018), with estate agents Sherry Fitzgerald reporting that figure has increased to 55% in Dublin in 2018. This has in turn affected employment within the country, with many companies reporting that foreign workers are reluctant to move here due to the lack of suitable accommodation. This research project aims to investigate if modular housing could be a suitable means of easing the current housing situation. The study will look at the feasibility of modular homes, with particular focus on construction, the benefits, challenges, the environmental impact and profitability. It will also look other various benefits and challenges of this type of construction.

the modular building process

Modular construction is the process whereby ‘three-dimensional or volumetric units’ (Lawson et al. 2014:P2) are manufactured off site, transported to site as the primary structural components of a building, and then assembled into place. This type of construction is generally used to create cellular shaped buildings, made up of similar sized room units which are then transported to site 70% to 90% complete (depending on the project). Modules can be fully compartmentalised or they can be partially or fully open-sided, whereby they are used as part of a larger structure. Also, modular units may be fabricated as certain elements of a building, such as

• Bathrooms

• Stair and lift units

• Mechanical units

• Prefabricated roofs (Lawson et al. 2014)

Modular building as a construction method aims to reduce the impacts of construction and can be used in many types of building, including housing, hotels, dormitories, and in commercial and retail. To allow great flexibility of design, wall panels can also be fabricated off site – these can then be used to add to the final structure on site (Quale el. 2012). One chief benefit of modular construction is timeline – the modules can be constructed while the site set up and the foundations are being prepared – this can typically cut construction times by 30% to 50% (Smith 2010).

benefits

Modular construction has many benefits as a construction method – this section will investigate the advantages that would be applicable to an Irish market.

Gibb and Isack (2003) carried out a survey of clients a found that the primary advantages were construction speed, increased quality, reduced cost, a reduction in waste and added reliability. Further to this, quantifying the benefits of modular construction can be best measured in terms of time, cost and specification. In modern construction projects however, there are many additional factors such as planning, building regulations, environmental and social impacts, which all have an impact on the project.

The main benefits of modular construction can be seen below:

Timeframe

One of the main benefits of modular construction is its timeframe. As site preparation and unit fabrication take place concurrently, the length of time from breaking ground to occupancy can be reduced. As material is on site for a shorter duration, risk of delays due to extreme weather, theft or vandalism are also reduced (Na 2007). In a study completed by Zenga and Javor (2008), they discovered that the average time required to construct a modular house was only four months, while construction of a typical home using conventional methods took 14 months. This can have a significant effect on cost too as much less labour is required on site. This leads to a reduction in site management cost and a quicker return on investment (Lawson et al. 2014).

Cost

Production in an off-site premises can lead to a reduced project cost in a number of different ways. Mass production of modules simultaneously can reduce cost as materials can be ordered in bulk, stored on site and protected from weather damage, while plant and labour costs on site are diminished. This can economies of scale in production, particularly if the project proposal is a standardised design. Furthermore, cost savings can also be made due to a reduction in site overheads, increased efficiency in installation and standard design. (Kamali and Hewage, 2014).

Site Safety

According to Lawson et al. (2012), in modular construction, reportable accidents on site have been found to be 80% lower compared to conventional construction. As site work is often carried out in close proximity with machinery, different work processes and different people, modular construction has a better safety record as approximately 85% of the work is carried out off-site. Working at height, harsh weather and dangerous work activities are other operations that can be minimised through use of modular construction.

Product Quality and Productivity

Due to controlled manufacturing facilities, task repetition and automation, product quality increases. Off-site production offers protection from the harsh site weather and where the work is typically less complicated, workers often become specialised at a quicker rate, leading to a higher level of workmanship. Output is also higher in modular projects as production is more structured, it has a more stable workforce and parallel operations can take place at the same time (Kamali and Hewage, 2014).

Other benefits include:

• As modular construction uses double skin panels, they often have superior acoustics, insulation and fire safety as each unit is constructed individually.

• Panels are lightweight, less material is used, less material is wasted and more material can be recycled when compared with standard construction.

• A reduction in noise, dust and traffic pollution throughout the project, which is of particular importance in built up/public areas.

• The units can be dismantled after use and they can be reused. (Lawson et al. 2014).

Challenges

Project Planning

Prior to any modular project, significant planning must take place. There are many challenges associated the prefabrication and assembly of the units, while design is significantly different from typical construction methods. Further considerations are required when incorporating various components within a unit, and when modules are transported to site, fitted in place and incorporated into the final structure (O’Connor et al. 2016).

Transportation Restraints

Transport restraints can impose significant logistical and financial issues for a modular project. Prior to a project beginning, many different logistical factors must be considered – limitation of transport links such as road width or bridge height, different transport regulations, traffic requirements or densely populated areas. Also, the method and route of transportation can dictate the weight, size and dimensions of a unit. Red tape surrounding transport of oversized units or customs delays at international borders can cause further delays (Velamati, 2012).

Initial High Costs and Site Constraints

While there can be cost savings with the mass production of modular units, the initial set up cost and the running of a manufacturing plant can be high. As modular construction is still in its relative infancy, there is a lack of widespread knowledge and experience by designers and engineers further inhibits its development (Haas 2002).

Environmental effects

On average, the built environment accounts for over 40% of total energy consumption in a developed country, and in order to reduce CO2 emissions, the EU has introduced its Energy Performance of Buildings Directive to reduce these figures. The directive has targeted the housing sector as one of the primary areas where these reductions can be achieved. A number of assessment methods are used to evaluate housing performances such as LEED, LBC and BREEAM. These assessment methods examine performance levels or expected performance levels of a building and allow comparisons with other buildings (Fowler and Rauch, 2006). With an increased emphasis on emissions and the life cycle impacts of buildings, sustainable construction has seen much more focus in recent times (Kandil et al., 2010).

Within modular construction, research by Kamali and Hewage (2016) have found a number of studies that compared the life cycle environmental impact of modular and conventional building. Many studies however, tended to focus on one or two criteria, rather than assessing the total footprint of a building. For example, Kim (2008) carried out a comparison of total energy use, greenhouse gas emissions and waste generation between traditional and modular building. Al-Hussein et al. (2009) compared CO2 emissions of traditional and modular building during the construction phase. Quale et al. (2012) quantified the total energy consumption from inception stage to the finish of both a traditional and a modular build, and compared the resulting environmental impact.

The results of the above studies had a number of common themes – a decrease in waste was found in modular construction, due to more precise planning and purchasing, more accurate cutting of materials and better recycling facilities (MBI, 2012). Also, modular buildings can be disassembled once their life cycle is complete and can be refurbished or relocated for use elsewhere (Kawecki 2010). While a traditional building can create noise and dust pollution, modular home reduce these by minimising time spent on site (Lawson et al. 2012). Greenhouse gases were also found to be reduced significantly through modular building through diminished energy consumption, fewer deliveries and fewer trips by suppliers and subcontractors. On-site reduction of greenhouse gas emissions is another benefit of modular systems. Reduced construction time leads to less energy consumption by plant and fewer trips by suppliers and subcontractors to construction sites (Cameron and Di Carlo, 2014).

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