Green roof perceptions: Newcastle, UK CBD owners/occupiers

Abstract

Purpose

The purpose of this paper is to explore perceptions of the advantages and disadvantages of green roofs for commercial real estate building owners/occupiers in a UK city and consider how these might affect the chances of their adoption.

Design/methodology/approach

Two sets of semi-structured interviews were conducted with purposively selected respondents, 10 with and 25 without green roofs, to compare and contrast differing perspectives. A grounded theory approach was taken to data analysis, allowing themes to emerge directly from the data.

Findings

Low awareness and understanding were observed amongst those without green roofs, which positively affected perceived costs whilst negatively affecting perceived benefits. Green roof owners gave weight to wider societal and ecosystem services benefits, whilst those without focussed much more upon building-level benefits and costs.

Research limitations/implications

Because of the restricted sample size, the findings in themselves are not generalizable; rather, themes are drawn from the research for reflection.

Practical implications

Findings point to steps that might be required of regional and national government to increase green roof uptake. This could involve initiating conversations to raise awareness, shift discourse and perceived norms and best practice; offering incentives, education and training; and presenting high-profile exemplar projects of green roofing to begin to mainstream the technology and get it onto the radar of building owners.

Originality/value

Bringing together social research around cohorts with and without green roofs, the paper throws into sharp relief discussions around costs and benefits and points towards potentially more productive directions for action to encourage consideration and take-up of green roofs by building owners.

Citation

Everett, G. and Lamond, J. (2019), "Green roof perceptions: Newcastle, UK CBD owners/occupiers", Journal of Corporate Real Estate, Vol. 21 No. 2, pp. 130-147. https://doi.org/10.1108/JCRE-11-2017-0044

Introduction

This paper explores barriers to the wider adoption of green roofs represented by the perceptions and attitudes of building owners/occupiers. It compares interview findings from cohorts with and without green roofs, to understand the potential for engendering more positive attitudes.

The paper argues that reduced awareness and understanding from businesses without green roofs means the technology is not on such businesses' radar. When asked to consider the possibility, concerns over costs and risks dominated thinking, whilst potential benefits were not easily perceived, believed or felt relevant. The paper argues that if authorities wish to improve uptake, then focus should be placed upon raising green roofs’ profile, helping them seem more possible and desirable and shifting norms and best practice. It concludes in asking whether this might be encouraged through more conversations around their wider values, explicitly addressing the spread of benefits and so fair allocation of costs and large-scale, high-profile municipal authority projects connected with professional and public education and training programmes. Professional guidance has been published by the RICS (Wilkinson et al., 2016), but awareness remains low.

A short literature review follows that briefly outlines the paper’s theoretical framing, then Methods and Findings, which continue the literature review in presenting and reflecting upon data, before discussing and concluding with significant observations and policy implications.

Literature review

In an ever-more urbanising world [UN (United Nations Department of Economic and Social Affairs, Population Division), 2014], the spread of impermeable surfaces increases apace as greater numbers live in urban environments (Jha et al., 2011). Increases in hard-standing through urbanisation and “urban creep” intensification (Wright et al., 2011) will impact flood-risk by reducing available permeable ground (Wheater and Evans, 2009) and a range of other ecosystem services (aesthetics, biodiversity, air and water quality, Gill et al., 2007; O’Donnell et al., 2017).

It is however possible to return parts of the built environment to a more natural state. When done sensitively, in the manner of Water Sensitive Urban Design (WSUD) (Wong and Eadie, 2000), this could also offer a range of ecosystem service benefits: improvements in aesthetics, biodiversity and air quality, etc. (Ward et al., 2012; O’Donnell et al., 2017), which may be of interest to policy-makers (Ashley and Nowell, 2010).

The retrofitting of green roofs offers a major advantage over other forms of urban green infrastructure in not requiring more land to operate (Digman et al., 2012). Unlike municipal infrastructure though, green roofs will require the approval of individual building owners and occupiers, as well as suitable properties for installation (Lamond et al., 2014b).

A range of literature has been produced around the viability, effectiveness and performance of green roofs in reducing water runoff and offering further benefits (Hoang and Fenner,2014; Wilkinson et al., 2016, 2015 and Oberndorfer et al., 2007). However, other published work has indicated that public awareness and understanding of green roofs remains low from the USA (Jungels et al., 2013) and Canada (Loder, 2014), through Spain (Fernandez-Cañero et al., 2013), France (Nappi-Choulet and Labussière, 2015), Australia (Tassicker et al., 2016), Iran (Kalantari et al., 2016) and Singapore (Yuen and Nyuk Hien, 2005), to Malaysia (Zahir et al., 2014) and Hong Kong (Zhang et al., 2012).

What has been less considered is perspectives and understandings of building owners/occupiers regarding units they control (Lamond et al., 2014a; Hendricks and Calkins, 2006). This is an important matter, because it is the perceptions of those positioned to install that will allow, or block, wider adoption. Perspectives will frame practice, so it is important we understand the former, to reflect upon what might influence the latter.

Poor awareness, understanding and lack of experience appear to be major barriers to wider adoption globally (Wong et al., 2005; Wilkinson et al., 2016; Kalantari et al., 2016; Zahir et al., 2014):

While green roof technology offers clear environmental advantages […] many building-owner respondents either do not know about or value these advantages. (Hendricks and Calkins, 2006, p. 148)

Green roofs have been argued to offer a variety of immediate benefits to owners/occupiers, such as thermal buffering or insulation (reducing the need for heating in winter and cooling in summer), reduced maintenance costs and extended roof life (Wilkinson and Reed, 2009; Nelms et al., 2007). However, it is clear that owners/occupiers and investors will not be the sole beneficiaries of many wider benefits; flood risk reduction, carbon/nitrogen sequestration and aesthetic improvements are shared across neighbourhoods and wider society (Lamond et al., 2014a). Although it is possible businesses may pursue societal benefits for purely altruistic motives (Olubunmi et al., 2016), it is more likely that neighbourhood and societal benefits will influence decisions if owners/occupiers see potential for these to feed back into business goals.

Two suggested routes for realising green roof indirect benefits are increased property value from uprating of a business area through increased traffic and increased profitability through enhanced company image (Nappi-Choulet and Labussière, 2015); a positive company image generated by Corporate Social Responsibility (CSR) has been shown to increase customer loyalty or intention to use businesses (Liu et al., 2014; Loussaïef et al., 2014). The potential to attract, retain and satisfy (thereby hopefully encouraging greater productivity from) high-quality staff is another CSR motivator (Klimkiewicz and Oltra, 2017; Loder, 2014). Of course, CSR can be manifest through social, economic or environmental means, and even within environmental themes, there are multiple actions companies can take to improve sustainability. However, using the built form to display environmental awareness has been a theme within the green building debate (Nappi-Choulet and Labussière, 2015). Arguably, a well-publicised green roof is a highly visual badge of CSR environmental commitment that can be exploited to gain potential custom and boost turnover. Businesses situated in central districts are best placed to use their real estate to influence brand image; however, different business sizes and sectors may anticipate variation in the impact of environmental CSR on their customer base.

The theoretical origins of the paper were loosely developed around the family of Rational Choice Theory (RCT) approaches (Scott, 2000), which assume that perceptions of costs and benefits will steer, if not determine, behaviour. A simplistic, but “thick” (Hechter and Kanazawa, 1997, p. 191), understanding of RCT was the starting point, accepting that all actors would have their own values affecting decision-making, but that they would be seeking some form of “benefit” maximisation, the details explored through interactions. CSR was incorporated as one type of perceived benefit (for the anticipated financial returns from improved image).

This worked in tandem with an understanding of the Theory of Planned Behaviour (TPB), which argues that people’s attitudes, subjective norms and perceived behavioural control will shape their behaviour (Ajzen, 1991); not that respondents would need any understanding of how to install green roofs, but rather whether they had a grasp of what green roofs were, how they function and whether their building might be suitable. A number of useful papers using TPB in a building and environment context have emerged recently (Wu et al., 2017, Suki and Suki, 2015), which gave the authors confidence in adopting this approach.

Importantly, the authors were not looking through one particular theoretical lens in conducting this research; rather, they were treating these as useful tools at the early stages of exploration, and as the results that will be discussed demonstrate, it emerged that such lenses would only be useful at a later stage once green roofs were on the radar for consideration by non-roof-owning respondents.

Methods

To address the paper’s principal question, the team undertook two stages of research, interviewing firstly those with and then those without green roofs. This involved a combination of purposeful and more convenience-oriented sampling (Marshall, 1996), targeting green roof-owning businesses and then willing CBD respondents.

Semi-structured interviews were used throughout, to encourage respondents to talk freely and allow new points-of-view to emerge (Wengraf, 2001). The interviews were digitally recorded, then transcribed and coded using qualitative data analysis software (NVivo) according to themes (Hilal and Alabri, 2013); coding and analysis was interpretive and entirely manual, rather than computer-aided, because of the small sample size and the feeling that this would allow deeper engagement with the data (Welsh, 2002). A grounded theory approach (Glaser and Strauss, 2009) was used in analysis to allow themes to emerge directly from the data. Because of the restricted sample size, the paper focuses upon observation of data themes rather than attempting to quantify or generalize findings.

Interview questions were developed from Lamond et al.’s (2014b) conceptual model of green roof benefits (Figure 1). The model presents findings from a systematic literature review, scaling out from the actual and perceived potential benefits for owners/occupiers, through neighbourhoods, to wider society and whole ecosystems.

Buildings with green roofs were sought in Stage 1 through a review of online information repositories (e.g. thegreenroofcentre.co.uk and ecogreenroofs.co.uk). Interviews were arranged and conducted with owners/occupiers of ten buildings (Facilities Managers of a mix of nine for-profit and not-for-profit organisations and one self-build owner-occupier) to explore awareness, understanding and perspectives. In Stage 2, a social research company was used to survey 25 owners/occupiers of buildings in the Newcastle CBD without green roofs to investigate the same areas.

The Newcastle CBD was selected for several reasons. Firstly, the city has a significant recent history of serious flooding, with the “Toon Monsoon” of 2012, where roughly 5 cm of rain fell in under two hours, flooding road links and causing severe traffic disruption (Pregnolato et al., 2017). Secondly, the authors have been involved with projects looking at Newcastle over the past four years, providing significant experience of the area, including a study that pointed to the viability of applying green roofs to a sufficient number of buildings in the CBD to help reduce flooding within the district (Lamond et al., 2014b). Finally, through collaborative work underpinning these projects, the Local Authority has expressed interest in green roofing, improving the sense of practical feasibility (O’Donnell et al., 2017).

The first stage of the research addressed 12 key questions and allowed understanding of the relative importance of benefits to emerge, and for new themes of interest to develop from those with direct roof experience. This then shaped the topics addressed in shorter interviews with CBD respondents, most of whom were less conversant with roof technology; again, 12 questions were asked, but elements were removed, whilst other relevant issues were added.

The great majority of CBD respondents were occupiers, with several managers from larger chains and a couple of owner-occupiers. This shaped the questions asked from Lamond et al.’s (2014a) conceptual model. Property value was in one sense less relevant, whereas the potential for increased traffic from district improvement was more germane (and would likely result in higher rental costs). Because of the layout and location of Newcastle, Urban Heat Island (UHI) effects were not relevant. Similarly, because respondents were owners/occupiers of existing buildings, neither was planning consent relevant, nor was reducing the need for drainage infrastructure, as drainage is not metered. Water quality benefits would further accrue at neighbourhood and society levels, with no requirements to monitor this for commercial use in the UK. Finally, carbon sequestration, erosion and stream degradation were neither directly asked about during the shorter CBD interviews nor did they come up in conversation, presumably not being of much concern to respondents.

Findings

This section presents findings in a manner consistent with Lamond et al.’s (2014a) conceptual model, working from the core outwards (owners/investors out to wider society/ecosystem), considering the above-mentioned exclusions.

Extending roof life

The literature has suggested that green roofs can extend the life of materials, protecting them from exposure to temperature changes and pollutants (Castleton et al., 2010; Nelms et al., 2007). This should result in reduced cost and disruption for owners/occupiers. Most GR respondents felt confident that such roofing would extend roof-life:

I think it preserves the length of life of the roof membrane […] it gives a more stable environment.

It lasts much longer because it doesn’t get overheated, or frosted.

A few felt unsure about the likelihood of extending their particular roof’s life, because of the building’s nature or the roofing materials used. Importantly however, they did not argue against the general principle of roof-life extension:

I’m not sure about extending the roof life, because it’s a timber building and because there’s various legal arrangements in terms of the site.

Many CBD respondents demonstrated lack of awareness and understanding of the potential for extended roof-life. The greater number expressed uncertainty (“I’m sitting on the fence on that one”, “that’s not a simple question”), a few said they would make no difference and a couple held that they could actually damage and so shorten roof life (“you need protection on the roofs and I wouldn’t say that would be protection”). Around one-fifth agreed that greening could extend roof-life (keeping it “safe from the elements”). It could reasonably be presumed that uncertainty might understandably tend building owners towards risk-aversion and so traditional roofing, where benefits are not foreseen, whilst greater risks are.

Thermal buffering

Greater awareness and appreciation of the thermal buffering qualities of green roofs (Fioretti et al., 2010) was seemingly exhibited by both groups. All respondents from the GR cohort expressed appreciation, whether or not it had been a direct consideration on installation:

It adds another layer of insulation to the envelope of the building.

We live in a cold climate, so thermal insulation is a motivation.

From the CBD cohort, the majority of respondents agreed in principle that green roofs should be beneficial in this regard:

I think it would help in lowering bills and energy efficiency.

I think these things provide terrific heat retention and it’s cooler in the summer as well.

However, a sizeable minority lacked certainty (“It does sound plausible”, “I don’t think so”), pointing again to lower awareness and possibly acquiescence, or social desirability, bias (Krumpal, 2011; Kuru and Pasek, 2016) whereby respondents either go along with an interviewer’s apparent preferences or provide answers they feel they “should”.

Reduced maintenance costs

Considering whether green roofs might lower maintenance costs (Gordon-Walker et al., 2007), GR interviewees gave a mix of responses. The large majority agreed that maintenance was low, strimming grass, removing young trees that had taken root and letting nature do the rest:

The main benefit is extended life of the roof and lack of maintenance – that’s zero maintenance.

The maintenance of it is purely cutting the grass and maintaining the drainage channels […] it’s quite happily doing its own thing.

A small minority, however, spoke of needing to intervene more, to preserve biodiversity and roof structure integrity:

If you leave it to its own devices […] it would probably turn into a monoculture of whatever was the most rank and invasive grass species.

[Our] suggestion would be that people consider, very carefully, the maintenance implications […] and then carry through with [the] maintenance regime religiously […]. That’s the area that’s much under-estimated.

The general CBD consensus was that green roofs would cost more to maintain, because of cutting back plants and clearing waste:

I suppose the maintenance costs would be up on the very little we pay to maintain our roof at present.

If it has more waste and gets blocked it probably gets more expensive.

A small number of respondents felt maintenance should be covered by the Local Authority, indicating a presumption that green roofs would be adopted under local government initiative rather than a building owner’s agency:

I would expect it to be covered by the whole NE1 thing [a Newcastle Business Improvement District initiative] we already pay for.

Surely it’s going to be managed by the City Council?

This points to the need to consider who would benefit from such roofs and who should pay, something that has been discussed by multiple authors (Lamond et al., 2014a; Tayouga and Gagné, 2016; Olubunmi et al., 2016). The respondent above mentions NE1, a Business Improvement District, which will be returned in the Discussion.

Stormwater attenuation

Moving on to matters concerning wider neighbourhoods, controlling stormwater flows should be a significant concern in locations such as Newcastle, which suffered badly the 2012 “Toon Monsoon”. As attested by the Commission for Architecture and the Built Environment (CABE) (2011) and a large number of other authors (Mentens et al., 2006 for a comprehensive literature review), green roofs hold the potential to quite significantly affect both stormwater run-off and the quality of water returning to watercourses following storm events; it has been argued up to a 54 per cent reduction in run-off for individual buildings with an “intensive”, or deep, green roof (Mentens et al., 2006).

All GR respondents were aware of and appreciated the roofs’ ability to attenuate stormwater flows. Half were not in areas at flood risk, so they had not been installed for this purpose, although with others this was mentioned as a concern and so benefit:

In torrential rain, you get a massive amount of water coming off [the roof] and it would overflow the gutters. It doesn’t anymore, because it just gets soaked in.

The green roofs were selected to help with attenuation in heavy rain – they soak up huge amounts of water and then release it slowly.

With the CBD group, less than half felt confident that green roofs could reduce flood risk, but the confidence of those who concurred was clear and strong:

I think it would help 100 per cent.

Having plants and green spaces […] would help, it sounds like a good idea.

Another quarter did not feel green roofs would make any significant difference:

It wouldn’t make no difference.

No, many things will affect flooding, that is not one of them.

Roughly the same proportion expressed a familiar uncertainty with regard to green roofs’ effects on run-off, again indicating awareness and understanding issues amongst those who had not previously considered installations:

I don’t know. I’m not really well informed about how it works.

I don’t understand anything about them, if I’m totally honest about it.

This lack of understanding could stand as a major barrier to building-owners considering green roofs in areas at flood risk.

Aesthetics

Respondents with roofs that could be seen by local residents or employees were happy to be able to offer aesthetic improvements:

Residents on the other side of the railway […] they weren’t looking at tin sheds, they were looking at something a little bit more attractive.

The pitched roof […] you look across the green area with trees and you see a continuation of the green area, so aesthetically, that was good.

The majority of CBD respondents sensed that they may improve the aesthetics of the city:

It would create a better-looking city centre.

It will make the city a lot more appealing.

Some questioned who would see them, however, and several felt that any change would be for the negative, for the public if not themselves, altering the appearance of buildings and moving away from tradition:

As long it doesn’t change the look and the tradition of the City.

It would probably be a problem in a lot of people’s minds.

This resistance to aesthetic change is understandable, as the character of Newcastle is important; parts of the centre are a conservation area, because of buildings’ heritage value. However, those most suitable for green roofing are generally more modern (Lamond et al., 2014b). The comments reflect that aesthetic tastes will differ and that local involvement will be needed to ensure installations create aesthetic improvements for most people.

Biodiversity

The great majority of green roof owners appreciated their potential for improving biodiversity. This was a significant motivating factor in only one case, but was clearly a concern at an organizational level to mitigate the potential damage of imposing more hard-standing and grey infrastructure upon the natural environment:

There are lots of different insects […] up there as well, so it’s quite diverse and vibrant up there after two years.

If you have a sedum roof, you’ve got all the birdlife, you’ve got the insect life on there, you see butterflies around there, you get everything.

Within the CBD, a quarter either said the roofs would not help with this in a city-centre location or expressed ignorance of the matter:

The only wildlife you’d get around here would be feral rats in the drains […] I wouldn’t say it would have any impact in the city centre.

No, I don’t think it would have any impact.

Around another quarter accepted that they could increase biodiversity, but felt this would not be a benefit, picturing biodiversity as more insects that they or other visitors would not appreciate:

I like the countryside, but there are loads of people in the city that don’t like the countryside.

Too many insects […] I don’t mind some but I don’t like them […] people don’t want insects or flies when they are trying to eat.

Such attitudes indicate that these groups did not associate biodiversity with the urban environment, possibly more with peri-urban and rural spaces. A small majority, however, did express appreciation for the benefits green roofs might provide:

For me that would not be a disadvantage, I am all for increasing the bug population.

It keeps bees, which is good for the environment.

Further multiple benefits

Whilst acoustic damping (noise attenuation) is considered a benefit of green roofs (Arthur and Wright, 2005; Ding et al., 2013), it did not appear a significant concern to respondents. Only two GR owners mentioned it as a consideration; no CBD respondents spoke of the issue.

Similarly, air quality was not much considered by the GR cohort, although when asked, respondents agreed. Almost all CBD respondents agreed that green roofs might improve air quality, although responses again indicated possible acquiescence or social desirability bias:

I imagine it would have a positive effect.

I think it will, be more green.

This supposition was somewhat strengthened by other CBD respondents indicating awareness and understanding issues:

If there is no pollution, air is not polluted by the rain.

It would make it worse – things would sink through the roof.

Unprompted, hardly any mention was made by either group of amenity. Several CBD respondents indicated they felt increasing the availability of CBD greenspace could improve the urban environment, but not did not connect this with green roof prevalence:

I think it would have a positive effect. Everyone wants to live somewhere green.

Everyone likes green areas in cities, it’s just more positive, helps the city in general.

This preference for the amenity value of street-level green infrastructure indicates a potential cross-over benefit of green roofs, were they visible to city occupants.

Image and social responsibility

Green roof respondents were generally very aware of the PR benefits potentially stemming from such roofing. This was not, however, admitted as a significant motivating factor by any, although to what extent responses were influenced by context is difficult to say:

Reputation-wise, I suppose it enhances the reputation of the organisation because it’s a clear demonstration of being environmentally sensitive.

Somebody sitting there who’s a green person, they’re more likely to come here than next door. We’re not sharply commercial […] there are a number of people it appeals to.

The implication is that installing green roofs was more a personal choice to be consistent with “who we are” than any public-facing concern. Whilst impressive at the individual case level, it does not offer insight into how the wider adoption of such roofs might be encouraged.

Most CBD respondents were not convinced that a green roof would have significant effect upon their business’ performance:

It wouldn’t make any difference.

I don’t think it would affect my business directly.

This is interesting, as one presumed motivator for businesses installing green roofs would be the “greenwash” benefits of doing something so public-facing (Olubunmi et al., 2016). However, a good number of respondents were working on the basis that roofs would be neither accessible nor visible to the public, negating most positive PR-feedback.

A smaller number sensed the positive potential from installing green roofs, whether for staff or potential customers, presuming the roof’s visibility and/or accessibility:

I think my staff and the people who come [would find it] much more pleasant.

I suppose it would be a novelty and people will go and have a look.

One respondent sensed a potential competitive advantage, were they the only business with one, but that if such roofs were city-wide, then this would be cancelled out:

If it was the only building or only two buildings, it would probably be good for public relations […] but if you have a city of that, it’s probably not going to affect the PR as much.

The respondent was thinking of individual competitive advantage over wider potential area benefits from increased footfall and commerce. If such views were held more widely, then a general consensus would need to be developed amongst building owners/occupiers around a “common good”, such that they might all agree to contribute and alter their roofing. Pursuing a green roof programme at a municipal level backed by Local Authority funding, awareness-raising and educational efforts might, under such circumstances, be a productive way forwards.

Who should pay?

As mentioned, there was generally a strong reluctance to the idea that businesses should directly pay for green roofs. For some, this was because enough taxes were felt to already be paid, such that financing should rightly come from local/national government resources:

It should come out of the council budget; we pay the council tax […] we pay late-night levies […] there should be enough money in the pot for that to pay for it.

We pay road taxes which should be used, not an additional tax, like an air tax and a looking at leaves tax.

Several respondents accepted that they might make contributions proportionate to business size, larger firms contributing more, to the point where smaller enterprises offered time and ideas rather than money:

I’m just a small business so I haven’t really got all that much extra to spare – that’s where big business could help.

Bigger businesses should give more and poorer businesses should give time.

Definitely not financial [contributions], I’d be prepared to input ideas.

However, shop-manager respondents of larger businesses were not convinced that their head offices would pay for green roof work, indicating that the displacement of financial responsibility could continue:

I don’t know if my business would pay for the green.

Certainly head office would be unwilling to contribute anything.

These strong objections to taking on costs highlight that CBD respondents did not see green roofs as their concern to take action over or that they might benefit from (through increased turnover and/or reduced absenteeism and increased productivity amongst staff, for example), but rather a matter for authorities to deal with; a number of respondents were happy to have green roofs, so long as they were not installed and maintained at their expense (including paid staff time):

As long as they’re going to take responsibility for maintaining it as well, and won’t leave […] the business-owners to pay.

Businesses have got to be streamlined; if they employ somebody who’s got time available to go and tend these gardens, they’re obviously not running the business very well.

These reactions point to participants not perceiving green roofs as bringing them significant benefits to balance against costs; instead, a sense from most that costs were upfront, yet benefits only potential. Several acknowledged potentially positive impacts upon the environment and so a moral imperative, but failed to connect these back to tangible individual benefits:

If you’re thinking morally towards the environment, it’s got advantages, but as a business-owner I won’t see any advantage other than, would my bills go down?

Such responses may have been coloured by the fact that these were small business-owners, wrapped up in the day-to-day concerns and pressures of making ends meet in an austerity-driven market. In this context, green roofs could appear a luxury concern:

A lot of people say green ideas are fine, but they cost, they cost, and people are in struggling times, in hard times – I don’t agree that it’s cost-effective

Discussion

This section will now review findings from the research, considering the relevance of the paper’s initial theoretical framing, the felt relevance of Cost-Benefit Analysis (CBA) and the possibility of considering a different approach with Business Improvement Districts (BIDs) as a way to encourage more buy-in to the idea of increasing the number of green roofs in the CBD.

Theoretical framing

Returning the Lamond et al.’s (2014b) conceptual model (Figure 1), this retains its relevance and would not in itself appear to need changing, although it would seem that the balance of benefit priorities could be altered for this small GR cohort. This would not in itself shift their placement on the map, although some might appear to be in danger of disappearing; the further multiple benefits, for example. Further, the low awareness of the CBD cohort has demonstrated that the model’s considerations are not yet relevant to those for whom green roofs are simply not on their radar.

If authorities wish to increase green-roof uptake, then as Wilkinson et al. (2016) note, this could be done voluntarily or mandatorily; a mandatory approach is presumed impractical for the UK given the socio-political setting, so it is presumed this will need to be voluntary. The question is how to encourage a culture and understanding whereby voluntary adoption might begin to happen.

It is evident that green roofs were not on the radar of building owners/occupiers in the CBD sample studied. This made the loose theoretical framings of RCT and TPB mentioned at the beginning less relevant; without prompting, respondents would not consider the actual costs and benefits of something they were not aware of or had no interest in.

When green roofs were suggested, perceived building-level costs and risks were more apparent to CBD respondents than actual potential benefits; wider benefits were less recognised and felt less relevant (not accruing to owner/occupiers). Unprompted, green roofs were not a consideration from an RCT perspective, and when suggested perceptions were skewed by misunderstandings, costs outweighed benefits, conversation closed. From a TPB perspective, respondents’ attitudes and subjective norms would be prejudiced against such roofing and their perceived behavioural control low because of lack of understanding.

Cost-benefit analysis

Lamond et al. (2014a) note a robust CBA around green roofs is still some way off. Contrasting papers have asserted that green roofs would pay back over the short term (Bianchini and Hewage, 2012), and that costs would never be outweighed by benefits, subsidies being required to motivate installations (Claus and Rousseau, 2012). Arguing for a quick pay-back might, therefore, be contentious.

The “business case” for direct benefits (extended roof-life, improve thermal buffering, reduced maintenance costs) and improved corporate image were acknowledged by the GR sample, but not admitted as driving influences behind installations:

We had to do a certain amount of it as a leap of faith […] we feel that it’s the right thing to do, we’ve got the opportunity to do it, let’s do it.

We did the green roof because […] we were wanting to be as environmentally good as we could.

It being “the right thing to do” and wanting to be “environmentally good” indicates that benefits beyond the building were more important than building-level considerations.

That the CBA is still debatable, and those with green roofs were not primarily motivated by such, points to such discussions not being where the conversation needs to be, for now. The issue is more one of encouraging shifts in wider societal discourse, perceptions of green roofs and environmental responsibilities, to affect attitudes (promoting “environmental citizenship”, cf. Dobson, 2007) more than arguments around monetary gain. At a later stage, thinking through the distribution of costs and benefits and realigning payment responsibilities to match would of course be imperative, but the first step must simply be getting green roofing on the table.

Several Newcastle CBD respondents were aware of this, observing that the profile of green roofs needed raising to generate interest and awareness and arguing that the Local Authority should set an example by establishing green roofs on its buildings:

I don’t think there’s a high-enough profile; it needs to go up to Council [Local Authority], to be advertised on TV, it’d raise awareness.

If the Council did a building with a green roof, that would sort of generate people’s interest.

Business improvement districts

This returns us to the respondent in Image and Social Responsibility who focussed upon individual competitive advantage over any wider gains from area uplift and the business-woman in Reduced Maintenance Costs who responded that she would expect green roofs to be paid for by the Business Improvement District (BID) NE1:

If it was the only building or only two buildings, it would probably be good for public relations […] but if you have a city of that, it’s probably not going to affect the PR as much.

As a business-woman I would expect it to be covered by the whole NE1 thing we already pay for.

Businesses within a BID will usually pay a percentage of their rateable value above business rates towards projects intended to benefit local commerce. Wolf (2006) has written about the Washington, DC’s BID work removing graffiti, street-landscaping and physical amenities, whilst Sheffield’s BID invested in flood-risk reduction (Environment Agency, 2014) and NE1 pays for street-cleaning and capital investment (NE1 2017). BIDs, therefore, already conduct works to provide commercial improving uplift, with commercial owners/occupiers paying towards these. As just one example of a possible direction of change, then it might be possible for Local Authorities and BIDs to work together to raise awareness and demonstrate the feasibility of green roofs, if convinced of their potential for economic and societal returns. Large-scale, high-profile projects with industry promotion could then help raise building owners’/occupiers’ awareness (Tassicker et al., 2016; Nappi-Choulet and Labussière, 2015), whilst projects linked with education, awareness-raising and “environmental literacy” conversations (Hoffman and Henn, 2008) as well as potential health impacts (Wilkinson and Orr, 2017) could begin to shift perceptions around their value.

It is important to note that although the paper’s findings would appear to be transferrable to other UK cities and beyond, further research may demonstrate other findings because of socio-cultural differences. Because of the relatively small sample sizes used, these observations should be understood as time- and location-specific indicative findings rather than overarching generalisations or anything more definitive. Further research in the field would, therefore, be encouraged.

Conclusion

This paper has explored and compared the opinions of owners/occupiers both with and without green roofs, in attempting to understand more about the blockages and potentials for increasing uptake. The study confirmed for a specific UK context (the Newcastle CBD) the lack of awareness and understanding of green roofs mentioned with reference to literature from around the world in the Introduction.

The opinions of green roof owners, whilst somewhat mixed, were found to overall be very positive about the wider value of such roofing and no respondent said they would not choose the same approach again. Interviewees tended to recognize many of the multiple potential benefits, both at building-level and beyond, and seemingly considered extra building-level costs as of little concern. None would appear to have prioritised cost-benefit analyses or externally facing brand image when considering such roofs; rather, this was a matter of consistency with organisational identity. For those without green roofs, it was apparent that lower awareness and understanding were leading respondents to focus upon building-level risks and costs of roofing, under-estimating, not considering or not valuing the multiple potential benefits at building-level and beyond. This understandably tended to skew preferences towards a more conservative position.

If authorities were to wish to increase green roof uptake, then several stages of activity might, therefore, be required: firstly, much wider conversations around environmental citizenship and the societal value of green roofs over and above their direct building-level costs and benefits; secondly, significant preliminary work around awareness and understanding concerning building-level costs, risks and benefits; thirdly, a series of policy decisions around the distribution of benefits and so fair allocation of costs and subsidies and, finally, a number of high-profile exemplar projects to demonstrate their practicability and effectiveness. All of these would be designed to begin shifting ideas around the possibility, plausibility and desirability of pursuing green infrastructure atop of the existing built environment.

The number of potential benefits of green roofing at wider neighbourhood and societal levels are multiple, and some area benefits (such as providing wildlife corridors and so hopefully improving biodiversity) will only emerge through their multiplicity and proximity. Green roofs are seemingly not currently on the radar of business owners/occupiers, so responsibility lands strongly on the shoulders of local and national government, possibly in partnership with bodies such as Business Improvement Districts, to push the conversation forwards.

Figures

Figure 1.

Conceptual model of green roof benefits (Lamond et al., 2014b, p. 6)