While at Wellington City Council working on Strategic Assets, one of the exercises of the Building Asset Team Leader, Tane Dunne, was to work out what the top major cost items were for the assets over a period of time, in this case 50 years.
The assets were captured by the SPM survey team of the housing portfolio of WCC which included about 1800 units. I am not sure how many units were used for the modelling. In the SPM data items were given unit or m or sq.m rates that are then used for calculations. What the basis of choosing these rates were I am not sure. Whether Rawlingsons Handbook was used and averaged over the country or by some other means.
The total costs, projected forwards over 50 years are then defined by component in the list below. These are maintenance items. Sums are at present day values projected forward.
Obviously the actual building components themselves are worth a reasonable amount and their value will go up due to compound interest over time.
The projected costs need to be budgeted for and sums allowed for the work split over the 50 years. It would need to be reviewed and adjusted for inflation but would be one tool that allows for a basic roadmap for maintenance.
As a designer I love this type of information, it adds a lot of weight behind advice I give to clients.
It is the type of information that can encourage the virtuous cycle of getting feedback from previous projects to constantly improve for the future projects. Taking lessons learned from earlier work and applying lessons to later work.
Number 1, paint finish.
An aesthetic, but also lasting only 10 years average, so may need to be replaced another 4 times in 50 years.
In NZ we now need to scaffold for external commercial work and cannot use ladders for some high work, also roofs need edge protection for working at height. With the cost of painting being high it would be worth exploring material lifecycles to see if more permanent finishes (Brick veneer, aluminum, PVC, Sandwich panels etc would be a better value external cladding requiring far less intervention for maintenance. At construction stage, they are more expensive, but over the life of the building, with less maintenance, they could end up being a cheaper solution.
Number 2, carpets
These are high wear items and also incur a cleaning requirement (that is not built into the above costs). The interesting thing is that they do not have a consistent wear over the whole of the carpet, mainly in heavy flow areas such as doorways and near joinery etc. There will be a variability of wear. One solution to this is to look at carpet tiles. If you have spare stock you could just replace the high wear tiles with new ones. The more modern carpet tiles are definitely more robust than the original tiles with curling corners and the underlays are pretty robust too. Obviously these are not the best solution in some cases but should be considered. Other more durable finishes can be considered too, such as polished concrete, commercial vinyl (in service areas and halls, not necessarily in units, although stained floors in cupboards and storage spaces may be appropriate.)
Number 3, Joinery fittings built in
These, in residential design are sometimes perceived as a fashion item and so replaced at intervals that bear no relation to their state, but in this social housing context one could look at what parts are failing, benchtops ? Drawers (mechanical sliding mechanisms etc)? For items that fail the most a more durable solution to that particular component could be considered, such as Stainless Steel Benchtops or even concrete benchtops and higher quality hardware for drawers. The original timber cabinetry from the 50’s/60’s has been replaced with meltica which is not as robust, but prices for flat packs are coming down, and as there is the opportunity to replace only a module rather than complete unit there are potential savings that can be considered when planning for these types of units in new units. In the late 80’s the banks went from owning branch premises to leasing premises. This led to a change in consideration of fitouts for branches. Instead of built in, there was a leaning towards free standing components , these could then be used in another branch when the lease was up for the current premises. In housing one could consider free standing wardrobes rather than built in units, these would possibly raise the cost for joinery but reduce costs for painting/carpentry as rooms could be more regular shaped and wouldn’t need doors/frames/skirting/scotia etc for the built in cupboards.
Number 4, Stoves
The high cost of these due to the type of asset, social housing. As a piece of equipment it is subject to wear, and must be provided by the landlord. All one can consider is finding a durable product and trying to keep a lot of spares for maintenance. If these are costly items then they should be monitored to see which brand/model performs the best and requires the least maintenance.
Number 5, Hot Water Cylinders
In NZ it is traditional to have stand alone HWC in each unit. Combined services reticulated systems with central boiler and storage have not been a traditional solution although it is far more efficient and cost effective. For large estates this should be considered as there are far fewer components that need to be maintained and the boiler can be run far more efficiently than hundreds of stand alone HWC’s.
Number 9 & 11, Timber and aluminum windows
In this blog I looked at component costs in the building and external windows were by far the most expensive items. Based on their location they can be a challenge to maintain and access also needs to be factored in for windows above ground floor. Timber windows do need more maintenance than metal windows and they are an important factor in heat loss due to the glass and air leakage around openings if they warp and do not seal properly. Planning for windows in the future should take account of potential energy savings for using double glazing, especially on East & South walls (where generally there are more service rooms ( and smaller windows) as main living spaces are usually planned to take advantage of sun on North and West faces).