7. Issues Specific To Maintenance And Rehabilitation
The environmental effects due to the huge amount of work carried out in maintenance and rehabilitation are far greater than the building of new housing. Although most of the principles and guidelines for the sustainable design of new build developments apply equally to rehabilitation schemes, there are subtle differences. Equally, the process of maintenance can have particular consequences for the environment if a strategy for sustainability is not pursued.
This Chapter provides additional guidance on areas specific to maintenance and rehabilitation schemes in the form of “at-a-glance” tables supplemented with commentary on key issues.
7.1 Maintenance Issues
Reviewing maintenance policy and procedures in the light of environmental consequences is an important step in providing a sustainable approach to managing housing stock. Housing providers should ensure that maintenance contracts come under the same scruntiny as new build contracts in terms of sustainable design and specification.
Figure 7.1 An old timber door can be maintained and will be in place for many years.
Figure 7.2 A new pvc door will be difficult to mend when it wears out at key points.
7.1.1 The myth of “maintenance free” components
Did you Know?
The maintenance and rehabilitation of dwellings forms 99% of physical housing activity in Scotland.
“Maintenance-free” products often involve replacing the whole component if it breaks rather than mending it. A sound maintenance programme that allows for ongoing repair and care for elements of the dwelling can save significantly on embodied energy over “maintenance-free” products which may have a relatively short life. One direct comparison here is UPVC with timber windows and doors (Figures 7.1 - 7.2). Good maintenance of high performance timber windows and doors can ensure that they last over sixty years. UPVC systems can begin to degrade, deform or breakdown after 10 - 30 years’ exposure to sunlight and can be difficult to repair.
7.1.2 Component lifecycles
Maintenance/renewal life cycles adopted for dwellings and their components tend to reflect mortgage terms (30 years is the most commonly quoted figure) rather than the actual lifespan of maintained construction. Components often outlast their predicted lifespans and are needlessly replaced on manufacturers’ recommendations or on the basis of established maintenance schedules rather than through rigorous inspection of individual items. Significant embodied energy can be saved through accurate and evidence-based maintenance schedules which are demand led rather than predicted and provided for.
| Site | Resources | Energy | Health |
|---|---|---|---|
|
communal planting
design land to be “owned” by individual occupiers effective maintenance cycle |
re-usable components
adopt maintenance policies that promote re-use of existing components use selective replacement |
glazing keep it clean, otherwise you are wasting solar energy avoid using inert gas filled double glazing as it will leak after a few years |
non-toxic paints, solvents, stains and sealants
specify low-odour or solvent free products use natural alternatives where affordable |
|
planting on buildings
climbers may need pruning 2/3 years water source to be within easy reach |
check component life cycles build up your own life cycle replacement programme based on experience of locality rather than theoretically | embodied energy ensure all replacement and maintenance products and components are as low embodied energy as possible |
timber treatment
avoid chemical treatment where possible provide adequate ventilation and eliminate moisture source |
| organic maintenance avoid herbicides, pesticides, artificial fertilisers to avoid health problems1. | local sourcing build up local maintenance contractors and suppliers | environmental products build up database of environmental products for maintenance |
re-wiring replace cabling with non-pvc alternative (non-halogenated cabling) provide demand switches in bedrooms |
| maintenance free planting use hardy indigenous planting and allow for wild planting areas to reduce maintenance2 | waste minimisation ensure all maintenance contractors provide waste minimisation plans | draught seals are usually the first item to go on doors and windows - check periodically for airtightness and replace if necessary | user control provide maintenance manuals to occupiers and ensure that they are fully aware of the planned maintenance programme |
| evergreen planting needs less maintenance than deciduous with less leaf fall to clear up | re-used materials store build up maintenance store of re-used materials from old contracts | gas boilers use simple technology that is replaceable and can be effectively serviced | ductwork and grills any ductwork and grills must be regularly cleaned to reduce dust and potential infections |
| climate change plan life cycle maintenance for increasing storm damage | water conservation ensure all new bathroom and kitchen fittings are water-conserving | renewable energy systems may have additional servicing requirements | user choice allow occupier a degree of choice on replacement units where possible |
| natural sewage systems need periodic maintenance to empty compost and other non-organic solids |
7.2 Rehabilitation Issues
In terms of sustainable design, most of the principles covered in Chapters 3 to 6 apply to the rehabilitation of housing stock. The decision on whether to demolish or rehabilitate old housing stock is based on a number of interrelated factors including desired housing mix, density, suitability of plan form, and state of repair (See Chapter 2). It is important to add the dimension of sustainable resource use into this equation also. Demolition always incurs the need for more resources than rehabilitation and this factor should be balanced against the others to arrive at a true evaluation.
Figure 7.3 Glasgow tenement awaiting refurbishment © John Gilbert “Tenement Handbook”
Once the decision has been taken to retain a building, the aim should be to fully exploit the environmental potential of the building using environmentally benign specification and minimising waste. There may be more restrictions with rehabilitation than with new build in terms of exploiting all sustainable design principles, but significant differences can be made with simple measures like retro-fitting insulation.3
Table 7.2 outlines particular considerations for rehabilitation.
| Site | Resources | Energy | Health |
|---|---|---|---|
|
site evaluation carry out careful site survey of existing micro-climate and note surrounding modifiers |
site and building audit carry out careful survey and record all materials and components that can be reused or recycled from existing site and building |
glazing avoid using inert gas filled double glazing as it will leak after a few years |
non-toxic paints, solvents, stains and sealants specify low-odour or solvent free products use natural alternatives where affordable |
|
passive solar check effectiveness of retrofitting passive solar sunspaces - avoid unless they can be easily built into existing structure (e.g balcony infill) alter window openings to suit 70/30% glazing ratio south/north where possible |
store and use reclaimed materials store existing reclaimed materials on site for reuse wherever possible advertise material that cannot be reused or send to central store |
embodied energy ensure all replacement products and components are as low embodied energy as possible |
timber treatment avoid chemical treatment where possible provide adequate ventilation and eliminate moisture source |
|
external porches add where applicable to prevent draughts and increase protection of main building fabric |
local sourcing source locally to match original where desired |
insulation
maximise and use “breathing” insulation where possible
avoid use of foams where possible adopt internal insulation where practical in preference to external insulation |
re-wiring replace cabling with non-pvc alternative (non-halogenated cabling) provide demand switches in bedrooms |
|
climate change check that existing details and drainage are strong enough to withstand increasing storm damage and rain. |
waste minimisation ensure all rehabilitation contractors provide waste minimisation plans |
renewable energy systems check orientation to see if active solar can be used |
user control involve occupants in design and specification for rehabilitation |
|
site history preserve significant components or parts of site which give continuity of meaning |
water conservation ensure all new bathroom and kitchen fittings are water-conserving install meters where appropriate |
CHP and communal heating consider this if existing layout of stock is compact can free up space in dwellings as boiler is omitted |
user choice allow occupier high degree of choice on specification and layout where possible |
|
communal planting protect existing trees design land to be “owned” by individual occupiers -split up site |
environmental products build up database of environmental products for rehabilitation |
||
|
planting on buildings apply trellises to support climbing plants where suitable |