Affordable Low and High-Rise Honeycomb Housing - 5 new articles
PART 1: LOW-RISE HONEYCOMB HOUSING
6.2 A Big Site
PART II: HIGH-RISE HONEYCOMB HOUSING
10.1 High-Rise Housing
13.1 The Singapore Experience
PART III: AFFORDABLE HONEYCOMB HOUSING
About the Author
The key inventive step in the Honeycomb apartment concept is the elimination of corridors and replacing them instead with of sky-courts. Re-inventing how residents are connected from the public street to their individual apartments overcomes the social problems that have been linked to the nature of corridors and “intermediate space” but also opens up to various ways of reducing costs.
The chart below that breaks down the selling price of a typical apartment helps us better understand by how much the checkerboard can help make housing affordable.
Here the components that make up the price of a typical apartment is listed with the bigger costs at the bottom. In this example, the biggest cost factor is land followed by the cost of architectural works, profit, car park, M&E services, superstructure, infrastructure, consultant’s fees, bridging loan, substructure, preliminaries, marketing costs and contributions.
The key thing about the Honeycomb checkerboard-plan is that it simultaneously attacks these multiple cost-centres:
From this list, all but two of the cost-centres mentioned above have been affected. But these two factors – profit and consultant fees – are calculated based on a percentage of development cost and when this has been substantially reduced, so can the amount of profit and fees for consultants. So, in both direct and indirect ways, we have shown that ALL the cost-centres have been tackled by the checkerboard design.
This validates the strategy that we have adopted. To really reduce the cost of homes to make them affordable, re-looking at the apartment typology and re-designing it from first principles offers a way forward.
10 to 20% SAVINGS
All these cost-savings point to checkerboard-plan apartments to be even cheaper to build than conventional high-rise.
A preliminary estimate of all the savings discussed above indicates that it is possible for affordable housing below RM300 per square foot to be provided in the major city centres where the price of land is within RM300 per square foot and where the density permitted is 130 units an acre and the parking standard is 2.2 car park per unit.
A COMPARATIVE STUDY
A study has been done to compare an actual project with a hypothetical Honeycomb alternative on the same site. We were able to enlist the help of the Quantity Surveyor of a real project near Putrajaya by PR1MA, a government-owned company tasked with delivering 500,000 affordable homes by 2020. At the time of writing, the project was at piling stage.Instead of two 15-storey blocks with a separate 6-storey car park block, we just had five 8 storey blocks on the car parking all on the ground floor. Naturally, there was a reduction in the construction cost per square foot of gross built-up area (GFA): just over 9% from RM119 to RM109.
Against this existing project based on a conventional design, a Honeycomb alternative was designed and it was costed by the Quantity Surveyor using information provided by Arkitek M Ghazali and its Structural and M&E engineers.
The initial result shows that the potential savings are as substantial as we expected. The following table presents a summary.
The average Net Saleable Area for each unit of only 88.11sm is increased by 21% to 106.75sm, but allied with a slight reduction in Gross Development Area: the efficiency of the layout, i.e. The Net Saleable Area as a percentage of the Gross Development Area has greatly increased from 49% to 60%. This means that there is a huge reduction in the construction cost per square foot of Net Sellable area of just over 24.8% from RM242 to RM182!
In this example, the Honeycomb alternative had a slightly lower density, 62 units per acre instead of 70. But with bigger units the Net Plot Ratio slightly increases from 1.52 to 1.56, causing a slight reduction in land cost per square foot of saleable area. With the land priced at only RM80 per square foot, the effect is not large.
However, with important land component of development costs virtually unchanged, the large reduction in construction cost has a more moderate effect on Selling Price: the alternative design can be sold at the average price of RM273 per square foot instead of RM323, a reduction of about 15%.
Table 2 A COMPARATIVE STUDY
This is well in the middle of our estimate for the cost savings achievable by the Honeycomb Apartment layout compared with conventional design. In this example, cost savings from construction was maximized and potential cost savings from land was not exploited because the land price was relatively cheap.
At RM80 per square foot, the potential savings from land did not merit the added cost of adding more residential floors and digging in a half basement car park. However, in cases where land is more expensive, the calculation would yield a different result.
Architects are not well known for helping to cut the cost of construction: it is said that every line an architect draws add cost. If so, it’s better that we not draw anything at all, just let the engineers or builders do it.
I write this only half-jokingly because it is a very common perception and, after these 20 chapters, I hope to have shown it to be wrong.
When I was one of several architects doing low-cost mass housing work for in the late 90’s, the client had in mind that we adopt a standard design and the design responsibility of each architect was to do the make -up work on the façade to give some sort of identity to each project.
The hope at that time was that the standardized design of housing units would allow Industrial Building Systems of constructions to be adopted, taking advantage of the large numbers of repetitive elements to be manufactured and assembled.
Speeding up construction time, minimizing wet trades on site, taking advantage of economies of scale, manufacturing techniques and reducing labour, especially the need for skilled labour, all these can surely help reduce the cost of building homes. But we must take a realistic perspective.
The cost of constructing a house is an important cost centre but it’s not the only one. There is the land to acquire, infrastructural services to provide and many other development costs to bear. Even just looking at construction costs, IBS mainly affects the cost of structural and wall elements, which in conventional construction only makes up about half of the building cost.
If structure and walls make up only half of the building cost and building cost contribute to only, say, 50% of the selling price of a home, then an IBS method of construction that involves only structure and wall directly attacks only a 24% component of the cost of construction, equivalent to roughly 12% of the price that a buyer pays for the home. So, if an IBS system saves 10% off the cost of structure and walls, this can only deliver a 1.2% reduction in price. From my experience, it is unrealistic to expect savings of more than a few percent of the total construction cost.
So, whilst better methods of construction should be pursued, we also must look for ways to reduce the cost of infrastructure, land and other costs.
A CASE FOR MORE RESEARCH INTO NEW TYPOLOGIES
This is where design can help. Not just another iteration of existing apartment typologies, but a more fundamental re-examination of how homes have been designed. This is the basis of our research into new typologies.
In our Honeycomb Townhouse concept, compared to terrace houses, there is at least 50% more units on each acre of land and construction cost is also lower due to the sharing of roof, suspended floor and foundation between the upstairs and downstairs unit.
Compared to conventional terrace townhouses, both the upper and lower-level units have gardens, two car parks and ample window openings for all the rooms. We have shown at our project in Alor Gajah that if priced about 20% lower than a terrace house with the same floor area, people will buy them.
We have discovered through experience that five-storey walk-up flat is the cheapest housing typology in Malaysia. However, the two highest floors were hard to sell even when sold at the heavily subsidized prices.
The V-shaped Honeycomb Medium-Rise concept provides a very inexpensive lift that only shuttles between the ground floor and 3rdfloor to serve all units, a communal courtyard for all, and private front-yards for some units, at an attractive block layout that achieves a density that is about four times that of terrace houses.
It is envisaged that if the typical apartment is priced about 20% lower than a terrace townhouse and 40% lower than a terrace house, people will buy them. This new concept might be suited at the edge of small towns.
In the suburbs of major urban centres where developers must provide low-cost housing, we have come up with the Kotapuri concept where the low-cost and low medium cost housing, priced between RM42,000 to RM100,000 are placed on top of shops. Although sold at a loss, the marginal cost of building each unit of low-medium cost unit is lower than its price; the marginal cost of building each unit of heavily subsidized low-cost unit is not too much higher than its price. In this case, the shops pay for the land and much of the infrastructure cost. In locations where there is no demand for offices above shops, it is better to use the space above it to provide housing units that liven up the area and provide housing for the people who tend the shops.
Designed and managed properly the commercial and residential components can add value to one another. In this way, the subsidized houses are located near amenities and public transport rather than shunted to the furthest, least attractive corner of a development.
In the Honeycomb apartment concept, the key inventive step is the elimination of corridors and replacing them instead with of sky-courts. Re-inventing how residents are connected from the public street to their individual apartments overcomes the social problems that have been linked to the nature of corridors and “intermediate space” but also opens up to various ways of reducing costs, making it possible to reduce pricing by up to 20%.
At the same time, we offer products that are more desirable, that can overcome the major social defects of high-density high-rise housing.
In the last few years, private and public developers have concentrated either on landed property that are expensive due to the escalating cost of land or else on high-density high-rise block that are very expensive to construct. These new low and medium-rise Honeycomb designs provide a wider range of alternatives that can serve an important gap in the housing market between terrace houses and high-rise apartments that most Malaysians cannot afford, and the subsidized low-cost and affordable housing that either lose money or provide thin margins.
When we look at major urban centres like Kuala Lumpur, Penang and Johor Bahru the problem of affordable housing appears daunting. The high price of land requires that very high-density apartments high-rise, but there is a cap on how many houses may be built on each acre of land. Even if allowed a higher cap, high-rise buildings are expensive to build. Not only the apartments, but also the multi-level car parking blocks that must be built.
Here, we look at a high-density apartment design that tries to overcome three hurdles that beset affordability in the main urban centres of Malaysia: how to reduce the high cost of land, the higher costs of constructing tall buildings and the cost of building car parks.
REDUCING LAND COST BY BUILDING MORE UNITS ON EACH ACRE
One way to reduce the cost of land is to have more units share this cost. But the intensity of housing development in Malaysia is controlled by restrictions on the number of housing units that can be built on each acre. At present, most local authorities still only allow high-rise housing up to a density of 60 units per acre, but official thinking about it is changing.
Why do Authorities want to impose density restrictions? The answer must be that people are worried about the negative effects of overcrowding. However, we have already made the point that as we build taller Honeycomb apartments, we also add more green, social spaces that be used for gardening, social interaction and children’s outdoor play.
If indeed, providing each home a private and a shared garden can overcome the social defects of high-rise housing, then why not allow even higher densities, especially if it is to make living in the city more affordable? Very high-density housing is already a fact, albeit under the alternative name of serviced apartments. However, serviced apartments that have been mainly built on prime commercial land have generally been too small and expensive, geared towards investors rather than home-makers.
The Draft National Guidelines on Planning (2013) proposes maximum densities of 60 units per acre for areas under District Councils, 80 units per acre for areas under City Halls or Town Councils and 90 units per acre for Transit Oriented Development within those areas.
PR1MA, a government company tasked with building affordable housing, especially for urban dwellers, has come up with guideline that allow for much higher densities than is normally approved. This is a snip from their guidelines:
According to this, the allowable development intensity for areas under District Councils is upped to 80 units per acre in a rural area and 80-120 units per acre in suburban area, for areas under Town Councils, 120-150 units per acre, and for City Councils, 150 units per acre.
Given how various government bodies are rethinking the issue of development intensity, it makes sense to make the case for allowing higher densities as a strategy to make housing affordable. Doubling the density of a housing development effectively halves the cost of land for each unit. Not only is that a significant amount for urban land, there are also additional savings in the cost of providing infrastructural services for each unit.
The range of high-density options that will be explored below will include all the higher densities that PR1MA has asked for, as well as a prototype for around 200 units per acre.
THE PROBLEM OF CAR PARKS FOR HIGH RISE
Malaysia is reputed to have one of the highest levels of car ownership in the world. The planning requirement for apartments is two units of car parks for each unit, plus another 10% for visitors. This is a very high requirement compared to most other countries and has the effect of making our high-rise housing expensive.
MEETING HIGH CAR-PARKING REQUIREMENTS WITH THE CHECKERBOARD PLAN
As we design taller buildings to achieve higher densities, just adding on parks on the ground is not the way to do it. The additional area required to cater for the additional car parks increase the development land required: since density is units/land area, increasing the numerator is pointless if at the same time, we increase the denominator.
To achieve higher densities, multi-level car parks are necessary. They can be placed in an adjacent block or below the tower. Constructing an adjacent block is cheaper but at the cost of being requiring an additional area, hence resulting in a lower density. But whichever of the two, the effect on the distribution of built-up area is that a large built-up area is now dedicated for cars: the net sellable area becomes a smaller proportion of the total built-up area. Car parks takes up a lot of space. Each car needs an 8’ x 16’ space that works out to 128sf. The driveway takes up 20’. All in all, with ramps and having to consider building columns and staircases, the gross built-up area required for one car park is about 260sf: in fact, actual car parks make up less than half of the total area of a multilevel car park block. Two car parks for each apartment plus another 10% for visitors takes up 572sf of car park built-up area. This is more than half the size of a typical affordable apartment.
Net sellable floor area expressed as a percentage of total built-up area for high-rise, including the multi-level car park plummets is often less than 55%. The fact is, the car parking requirement for high-rise high-density housing has become a very heavy burden on the cost of construction.
Again, PR1MA is aware of this problem and have produced their own guidelines which try to address this problem. In their table, A1, the car park provision for rural areas is set at 2.2, suburban and urban areas at 1.65 and 1.1 in cities. Although this standard may face resistance from local authorities and householders used to the convenience of having two cars, in the longer term, promoting a less car-dependant life style makes sense.
Already, the average size of households in Malaysia has peaked , bringing down the average number of cars per household. With the expansion of public transport in Kuala Lumpur and the Klang Valley, plus the explosive growth in share-riding services like Uber and Grab, owning a car is not essential for young working people, as it once was. I believe that PR1MA can do a good job in convincing local authorities home-buyers to buy into the concept of the compact city that promotes high residential density, mixed use and is oriented towards pedestrians rather than cars.
The efficiency of car parks can be operationally improved by doing away with parking spaces that are strictly allotted. As currently practiced, car parking spaces are allotted as accessory parcels to each owner. However, this ends up with a lot of car parks being empty for long periods. A pooled system, as found in commercial buildings, can cut this slack, providing more car parking opportunities with fewer actual slots.
In fact, PR1MA’s guidelines presumes only two basic options – a stand-alone multi-level car park or a podium car park that sits below the building block.
Figure 15 Multi-level Podium Car Park
The latter is of course more efficient than the former. But the podium is still a poor choice. The podium takes up space larger than footprint of the tower or slab block above it. This increases the land area that is needed. The car park podium also must be set back from the boundary by about 50’ from the front and 25’ from the side. Having to do so results in having fewer cars than car parks on the ground floor which are subject to much lower setback lines.
Is there a better solution?
DEEP PLANS: PROVIDING CAR PARKS MORE EFFICIENTLY
The checkerboard-plan was conceived to be car park design-friendly with columns spaced in an 8m grid. A car park circulation system also fits neatly into the 5-layered grid with two roads inside the building footprint feeding car parks on both sides.
Figure 16 Columns in 8.1m grid
There is a road that circles the outside of the building: it too feeds car parks on both sides. The ground floor plan is shown below.
Figure 17 Ground Floor Car Park Plan
On just one floor the design is already very efficiently with up to a density 136 units per acre and this one floor is good enough to support a residential density of 60 units per acre when the car park requirement is 2.2 car parks per apartment, 90 units per acre when the car park requirement is 1.65 car parks per apartment unit, and 120 units per acre when the car park requirement is 2.2 car parking spaces per apartment.
But can we provide for even higher densities? Is there an alternative to the conventional multi-level podium car park?
Our answer is to replicate the ground floor car parking layout in a basement floor. In fact, basement car parks are generally not considered at all for residential development because they are thought to be costly to build, needing temporary shoring and permanent waterproofed retaining walls, and costly to maintain, with a mechanical system to draw in fresh air and expel fumes as well as a smoke-spill system in case of fire.
Yet, a single basement level 7’ or more away from the boundary does not need temporary shoring or an expensive water-proofed retaining wall. An 8’ rubble retaining wall at the boundary plus a low 1’ concrete one on the car park building line will suffice, creating an air-well that provides natural ventilation, daylighting, a green planting strip and setback distance to meet current planning requirements.
Figure 18 Perimeter Retaining Wall and Air-well
It is also easy to design an access to a single basement floor, doing away with having too many ramps as shown in the plan below.
Figure 19 Basement Car Park Plan
As shown in the basement car park plan above, just two car park levels can already support a building above it that contains 133 units per acre when the standard is 2.2 car parks per acre, 170 units per acre when the standard is 1.65 car parks per acre, and 275 units per acre when the standard is 1.1 car parks per acre.
The options available are displayed in the drawings below.
A design strategy that achieves high-density with shorter buildings and which either eliminates the car-park podium or else substitutes it with a low-cost single basement floor will surely reduce construction cost and time. Combining it with a lower car parking standard and as well as a loosening of the cap on density will further multiply the savings.
Back to Table of Contents