Keywords

Deconstruction; materials reuse; waste recovery; waste minimization; recycling

15.1 Introduction: a domestic eco-refurbishment

In 1998 the author was commissioned to carry out a major domestic eco-refurbishment and upgrade of a 1950s house in Wellington, New Zealand. The clients wanted an architectural solution which was at once ecologically and environmentally sound, aesthetically pleasing, comfortable, healthy, and life-enhancing, but also built within the standard budgetary constraints of a normal home. The house also had to be adaptable to the changing needs of the owners and be a sound financial investment. A benefit of refurbishing this existing house was that it was built with good-quality, durable materials, mainly heartwood from first growth native New Zealand timber. Using this kind of timber is of course not a sustainable, or indeed possible option for new buildings (see Chapter 2), so this was an added reason to ensure its careful reuse. Despite being built well, the house was poorly planned, spatially mean, crudely built, and not compatible with the user’s existing or future lifestyle intentions. It did however occupy a wonderful site, an easterly facing steeply sloping section, sheltered from the predominant northerly and southerly winds, which had delightful and expansive views across Wellington harbor and had good exposure to the northerly sun. The redesign created an expansive, highly crafted, comfortable, and life-enhancing home. Scenario planning was used to ensure that the home could be readily adapted to changing client lifestyle demands. The design successfully incorporated passive solar design principles, the use of sustainable and healthy new materials, and a series of crafted elements to give continuing delight and pleasure to the owners.

One of the major design strategies involved was to reuse as many of the existing building components and materials as possible, consistent with satisfying the stringent design intentions and the New Zealand Building Code. This involved a significant amount of deconstruction of the existing building.

The New Zealand Building Code requires that all building materials used structurally, whether new or reused, must be certified to last for at least 50 years in the specific context of use by a structural engineer. New or reused cladding materials must have a certified lifespan of at least 15 years and all other materials 5 years. If a designer chooses to reuse components and materials they become the de facto certifier and if failures occur within the designated durability provisions, the “certifier” can be sued. In this case reused structural members were examined by and certified by the structural engineer and the architect examined and certified the other reused components.

15.2 The builder and the clients: commitment to resource savings

While both the architects and the clients were committed to creating an ecologically and environmentally friendly outcome it proved to be extremely difficult to obtain the services of a building contractor who shared these intentions and was still able to produce good-quality work at an affordable price. In the end, a builder was employed who had a good track record in conventional building work but little knowledge of sustainable construction.

A good deal of extra time and effort were spent on preparing documentation and in explaining the ecological design intentions to the main contractor and his workers as well as his subcontractors, but this approach met with only limited success. Fundamentally the principal contractor sought to avoid any extra work or costs that the ecological and environmental intentions of the project imposed and did not instruct his own workers or his subcontractors concerning associated contractual requirements. It was left to the architect and the clients to catch deviations from the specifications and drawings.

The clients remained on site for the whole of the duration of the contract and were extremely conscientious about informing the architect of possible deviations from the terms and conditions of the contract. The architect spent considerable extra time in following these reports through and insisting on compliance with the contract. In the end the contractor realized that it was going to cost him less time and expense to comply with the contract documents than to attempt to circumvent their requirements. Things started to improve from then onwards but with a constantly changing workforce, numerous subcontractors, and an essentially uncommitted main contractor, compliance remained an uphill battle throughout the duration of the contract.

15.3 Reusing windows and doors

The reuse of doors and windows was seen from the very beginning of the design as both an economic and a resource-efficient approach to the redesign of the house and a worthwhile objective in itself.

Windows and doors have a major impact on the visual coherence of any building. Great care was therefore taken to integrate existing and new windows and doors and to create a unified architectural expression for the building as a whole and for each of the spaces, while still seeking to create a modern architectural statement. Externally, painted timber componentry is the obvious unifying factor but fitting the new windows into the existing overall architectural form of the building and retaining a similar scale and proportion in the new work are in fact the primary contributing factors to the deliberate, visually cohesive integration of old and new. Modern timber sections were deliberately used in new work rather than seeking to replicate the original sections, as the new sections work better and were less expensive and resource-intensive than trying to match the existing sections in the new work.

Internally there were three conditions, one where the original component was retained in its original location, one where existing components were relocated and reused, and one where new components were used. New windows and their linings and architraves were clear finished internally; reused windows and their new linings were painted internally but their architraves were clear finished; and existing windows with their linings and architraves were simply repainted. Only new windows or reused windows or existing windows were used in any single space. They were never mixed. The notion here was to provide a resource conservation and historical code that was understood by the clients but was not readily apparent to the casual observer.

All the existing windows except one small unit and all the existing external doors except one were reused in the upgraded building. All interior doorsets except three were also used. All internal window and door sills, linings, and architraves had to be replaced in the reused windows and exterior door and door screens because the original sills and linings were inevitably damaged during extraction of the windows and doors from their original locations.

Some limited adaptation of three of the existing windows occurred by way of removal of one of the sashes in these multisash windows, but in all other instances the whole window was reused. All reused windows and exterior doors had their hinge actions eased and were weather-stripped to control draughts and heat loss. New hardware was fitted to provide additional security and design consistency and because, after nearly 50 years of constant use, much of the existing hardware was in poor condition.

Interior doors were paneled to unify them visually with new doorsets and consequently the rebates in existing frames had to be deepened. Work on all relocated windows and doors was undertaken in the contactor’s own joinery shop while work on windows and doors retained in their original positions was carried out on-site by joinery shop staff. New architraves and hardware were provided for the reused interior doorsets. Three interior doorsets were riddled with borer and could not be reused. Financially the reuse of the existing windows and exterior door components generated significant cost savings, but the reuse of interior doors was less financially beneficial and resulted in only marginal savings. Both resulted in considerable resource savings.

15.4 Reusing the roof

The clients were very concerned at the lack of head room in the existing house and the architects were required to address this deficiency in the redesign. The existing roof was a minimally angled monopitch, with a multilayered bituminous felt finish laid on timber boarding and beams, with an uninsulated flat ceiling below. The felt was at the end of its useful life; it leaked and was very unsightly. External appearance was important as the building is approached from above and the roof is in effect the fifth elevation of the house.

The architects wished to retain the existing sound roof structure and decided to add a new weather skin above the existing roof supported by this existing roof structure. Initially the architects designed a solution which involved cutting the existing roof boarding and weather skin along the line of an existing, longitudinal structural wall and lifting the roof above this to create a double-pitched roof with a skylight ridge. This involved pivoting the roof structure on the external walls and building up the central structural wall. A specially designed, structural, gusset plate connector was to be utilized to close the gap created at the ridge.

Client, architects, structural engineer, and quality surveyor were all happy with this solution but none of the tendering building contractors would quote for carrying out this part of the work. All the contractors were concerned about the roof being lifted off the wall and damaged by the wind during the pivoting operation. Wellington can be quite windy but in fact this site is very sheltered.

Reluctantly the architects redesigned the roof. In the final design the existing roof was left in place and a new monopitch corrugated metal weather skin fixed on top of this on battens, with a ventilation gap between the two roof finishes as in the previous design. The flat ceiling was removed and a sloping ceiling was incorporated which followed the underside of the existing beams to improve head height in the main living spaces. The intention was to reuse the ceiling battens to construct the new ceiling. However, some of the existing beams and battens had warped and for the eastern two-thirds of the ceiling it was necessary to remove the existing ceiling battens and replace them with low-profile metal levelling laths. This lost a very precious 25 mm of the floor to ceiling height but resulted in a very good-quality ceiling plane in the large living area spaces. Existing ceiling battens were reused in the westerly third of the ceiling and within the utility and kitchen areas. Wool insulation made from recycled carpet offcuts was incorporated throughout between the existing beams.

Initially the changed design was regarded as something of a compromise but it worked out very well. The final design was less costly than the original and the increased height generated within the living spaces by taking the existing ceiling void into the rooms proved to be perfectly satisfactory to the clients. Indeed, the new living areas now have a very generous, spacious feel. The main living spaces open to the sun rather more in the final design than in the original redesign. This has the effect of making views more expansive, but increasing solar penetration in summer causes some overheating on summer mornings. This is easily dealt with by opening doors and windows at either side of the house for a few minutes.

There were a number of additional bonuses associated with reusing the existing roof. Metal roofs are notoriously noisy. The noise of raindrops hitting the roof and creaking associated with thermal and wind stressing is often transmitted to interiors, and can be quite irritating. In this building the noise transmission is well muffled so interiors are significantly quieter in all conditions. Overheating of the interior through the roof in summer is mitigated by the double roof and the ventilated roof cavity. The internal insulation value of the roof is also increased.

The weather protection created by retaining the existing roof enabled work to proceed on-site even on very rainy days and protected the existing hardwood floor and the lower storey of the house.

15.5 Recovering existing fittings and fixtures

The specification required all existing fittings and fixtures which were not required for the renovated house to be carefully removed and handed over to the client. The client in turn made strenuous efforts to reuse or sell the recovered fixtures and fittings. One of the kitchen worktops was adapted and now serves as a desktop in one of the studies. The other kitchen cupboards and worktops were adapted by the client’s son and now serve as workshop benches, cupboards, and shelving in the garage. An existing bookcase was moved and adapted for use in a study area. A number of other fittings were disassembled and the timber stored for future use.

Recycled native hardwood was used to make a purpose-designed vanity unit for the main bathroom. This was costed and proved to be no more expensive than an off-the-shelf unit using new materials. The purpose-built recycled hardwood vanity unit is a very pleasing and successful feature of the bathroom area.

15.6 Materials: minimizing waste

The general policy was to retain as much of the existing materials on-site and minimize waste sent to landfill. Considerable efforts were made to devise ways to incorporate as much of the existing materials as possible into the renovated building.

15.7 Conclusions: intentions, attitudes, and realities

The attitudes of both clients and contractors are key factors in achieving successful outcomes in the area of deconstruction and resource reuse and recovery. In this instance the architects and clients were in total accord on this issue and sought to practice resource recovery in all aspects of this project. These intentions were backed up by carefully written specifications and contract documentation and by close observation of the works by client and architect.

Despite this, not everything went smoothly. Some of these difficulties can be attributed to the unsympathetic attitude of the contractors to resource conservation issues and sustainability in general. This attitude can be observed in the very low recovery rate achieved for the cedar siding. Being more careful would have probably resulted in a significantly higher recovery rate but the contractor believed that it would have cost him more time while using new materials would “only” cost the client and the planet.

Interestingly, it proved quite difficult for the contractor to source materials of adequate quality to match the existing weatherboards. This caused delays in achieving weathertight enclosure which had quite significant “knock-on” effects. In the end these delays probably cost the contractor more than the extra over cost paid by the client for the new materials, so everyone was the loser in this instance.

The attitude of the contractor made achieving resource recovery measures and getting sustainable new materials delivered something of a challenge, but his work was of a reasonably high standard and generally once he had committed to a course of action the result was good. This was the case in relation to the roof, the reuse of windows and doors, and the removal of fixtures and fittings. Only in the areas of disposal of excavation materials and recovery of weatherboard sidings was his performance disappointing.

The diligent observation of the works by the clients and the architect, together with the insistence on compliance with the contract specification by the architects throughout the project encouraged the builders to stick more closely to the contract requirements for resource conservation than they might otherwise have done.

The obvious lesson here is to only employ contractors who are sympathetic to the objectives and intentions of the clients and architects in relation to deconstruction and reuse of components and materials. This is quite easy to say but not quite so easy to do.

Wellington would benefit from a “Green Builder” program like that established in Austin, Texas in 1992. In this program, builders are encouraged to learn about and adopt sustainable construction practices by participating in an active education and support program provided free of charge by the City of Austin. Registered Green Builders are able to rate the houses they build under an environmental rating system controlled by the City and thereby obtain a marketing edge over their rivals. Providing both the educational support and business incentives to encourage the involvement of builders is a vital aspect of achieving sustainable architecture in practice.

On the positive side there was very little waste. Expensive, resource-intensive elements like windows, doors, and kitchen cabinets were virtually all reused or were handed over to the client for future use. The roof was also reused. Sanitaryware and hardware was, after 50 years of constant use, quite worn out and beyond salvage. Only small amounts of concrete, timber, and assorted rubbish and modest amounts of excavated material were landfilled. Despite the small quantities involved, it would have been preferable to dispose of the asbestos-based tiles and treated timbers in a safer manner. Instead they were disposed of with other material in the hazardous materials section of the local landfill. There was at the time no alternative disposal method available in Wellington. Table 15.1 summarizes the recycling, reuse, and disposal methodologies employed for each material.

In the end this renovation was an exercise in the art of the possible. Nothing was done in this project that could not be done easily in any other project. The deconstruction and resource conservation measures taken resulted in both financial and resource savings. It could be argued that both the clients and architects had to put in considerable extra time and effort to achieve the results obtained but both were committed to this course of action from the beginning and both knew that the deconstruction, reconstruction process embarked on would require them both to put in this extra effort and commitment to obtain the desired results. However, in an age of competitive fee bargaining not many architects feel able to devote the considerable extra time to save their clients money or the world resources, and even fewer clients are prepared to pay extra fees to make such resource savings. This is a considerable disincentive for architects to undertake resource conservation measures in the normal course of events.