Art deco home, Hamilton - deconstruction

Deconstruction is the process of taking a building apart, storing and handling materials in a manner that achieves maximum salvage and recycling of materials and safe removal and disposal of hazardous materials. This results in the dual benefits of reducing landfill/cleanfill loadings as well as reducing the use of new materials.

In many ways, deconstruction is the opposite of demolition, as it is more considered and resource conserving. It is not yet common in New Zealand for domestic buildings, probably due to the slightly higher upfront costs compared to conventional demolition. However, the additional costs are to some degree balanced by the savings incurred from not having to purchase new materials. What the savings are is largely dependent on the quality and cost of the materials that can be salvaged. For those who are not interested in reusing the materials on site, there is the option of on-selling the items.

This case study examines a 95 m² single-storey art deco house in inner city Hamilton, which was at the end of its useful service life. The home's condition was established via destructive inspection.

The inspection revealed that major renovations would be required that would result in:

• significant environmental compromises, especially in terms of key passive solar design goals
• extra costs associated with matching imperial with metric material sizes, which occurs in any renovation of older buildings.

In addition, a good deal of uncertainty surrounded the extent of dry rot in the timber framing, which meant that establishing the size of the renovation was impossible until all interior linings were demolished.

Given the owners' keenness to develop a high-quality high-performance house with a low environmental impact, it was soon realised that a renovation would have meant too many compromises - especially in terms of the passive solar design targets. As the house was reasonably well located to amenities, achieving a Walk Score of 47 (see www.redfin.com/how-walk-score-works), starting anew seemed a good option in this particular case.

Planning the process

The owners realised that the better the planning early on, the more chances there would be for salvaging materials, fixtures and fittings. A variety of issues needed addressing, such as:

• what could be practically diverted from the landfill (likely markets and outlets)
• where could things be stored on site while the new house was constructed
• where could items not being reused be sold or rehomed
• what information would be most useful for the deconstructors (in this case, the builders) to carry out their job most effectively
• what were the responsibilities of each of the interested parties (i.e. owners, builders)
• what REBRI information could be applied to this project
• what consultancy information the local Eco Design Advisor (EDA) could provide to fill the gaps.

All site workers were informed of the overall goal and undertook to work with this in mind. The builder was specifically chosen for his interest in the owners' goals around low environmental impact design and was keen to try out the new approach. The chance to rehouse materials/fixtures was explored. Neighbours and friends were informed of the upcoming availability of surplus materials/fixtures and given the opportunity to salvage discrete items. Finally, Trade Me and the Yellow Pages were used to dispose of some items, while the local Hamilton EDA provided alternative disposal options for the more challenging materials.

What was salvaged?

The bulk of the deconstruction happened over a 5-day period - slightly longer than a similarly sized typical demolition project, which would usually take around 2-3 days. However, the gains in terms of diverted and salvaged materials were considerable, and the owners considered the project overall cost-neutral. The destination of the majority of the building materials and the amount salvaged is shown below.

Volumetrically, the two largest materials by far to be sent to landfill were the fibrous plasterboard and wire-reinforced stucco work. Since these were co-mingled wastes (i.e. they incorporated several materials mixed together in a way that could not be easily separated and therefore made use of), they ended up being landfilled.

The recyclability of some materials such as the flooring joists and studwork proved challenging in practice. The joists were very dry and therefore split very easily, making salvaging them in their entirety difficult. The majority of the studs had rebates due to the diagonal timber cross-bracing elements. This resulted in less reusable wood for furniture purposes and more fuel wood for home heating (approximately 4.4 m³ in all) being generated than was initially hoped. In terms of heating energy provided, 4.4 m³ equates to approximately 8,000 kWh of heating, which would fuel a typical house for two winters using an efficient burner (at 70%).

On the positive side, a few unexpected things ended up being reused. These included the television aerial, curtains (complete with tracks and clips), windows (inclusive of the surround) and even the toilet pan/cistern. The temporary outhouse (which was used during the construction process of the new house) was almost entirely made of salvaged materials from the old house - toilet, cistern, timber framing and old-style corrugated iron. The only things new were the nails holding it together and the water feed line!

The most successful recycling (or upcycling) outcomes, were:

• the old, formerly carpet-covered T&G rimu floorboards being transformed into polished, polyurethaned floorboards in the upper storey of the new house
• the old rough-sawn rafters and roof trusses being upcycled into high-quality furniture (such as a dining table), stairs, stair handrails and kitchen and bathroom benchtops in the new house.

Keys to success

So what made this project successful? In this case, success relied on good planning combined with willing participants. Key to this was finding creative solutions to maximise the salvageable material available right throughout the deconstruction process. Specifically, this included finding viable markets (especially within close proximity), coordination of works, overcoming physical site restrictions (especially for long-term material storage) and effective communication between the parties involved. The extensive REBRI resources on material salvaging were much appreciated as was engagement of the builders.

At project completion, a more critical examination of the benefits - both societal and personal - could be performed. The project benefits were seen mainly as:

• lowering the environmental burden associated with landfill and cleanfill
• providing some continuity between the old house and the new via the reuse and (in some cases) upcycling of material
• revitalisation and rejuvenation of something that could easily be discarded and landfilled into something that is functional and appreciated every day.

These benefits should ideally be factored in.