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Steps of Choosing the Right Land/House for Redevelopment

Updated: Oct 15, 2021

"Looking to build your dream house but ensure of what you should note for redevelopment? Get all your answers here!"

Due to feedbacks received, I have decided to come out with a post to go through the steps when considering to purchase a house or land for redevelopment. This post hopes that it will be easier to guide the reader to be conscious of all the consideration and steps required before making the purchase!

Step 1:

Evaluate if redevelopment satisfy your needs! Redevelopment is a relatively long process ranging from 2 years to 4 years depending on the complexity of the design and if owner is decisive. I have experience during my time as a Civil Consultant Engineer where the design stage dragged for more than a year as the owner kept making revisions after the design has been produced. Construction duration varies between 1.5 years to 2.5 years depending on site constraint and complexity of the design.

You also have to be aware on the construction cost involved. The cost will depend greatly on the site constraint, finishes of the house and the complexity of the design.

Step 2:

What type of landed house do you wish to build? Terrace, Semi-D or Detached? Based your desired type, we have to check if the land size and plot width is sufficient.

For Bungalow Houses:

For Semi-detached Houses:

For Type I Terrace Houses:

For Type II Terrace Houses:

Upon confirmation on the adequacy of the land size and plot width, we have to check if the landed neighborhood allows for your desired type to be built based on URA guideline. For example, not all landed estate allows terrace to be built. Therefore, it is not possible to acquire a detached or semi-detached house and rebuilt it into two or more terrace house by land subdivision.

Step 3:

Decide if you require a 2 storey or 3 storey house as not all landed estate allows for 3 storey house for example Hua Guan Ave.

2-storeys Envelope Control

Image Source: URA

For a 2-storeys envelope control, a maximum height of 8.5m is allowed excluding the attic. A maximum height of 3.5m is allowed for the attic. However, the attic requires a 45 degrees pitch line from the setback line which does not allow any structure to be built above this line. Hence, it is very common to see most landed houses have unsheltered balcony at the front and back of their highest floor.

3-storeys Envelope Control

Image Source: URA

Similar to 2-storeys control, the attic is set at maximum height of 3.5m and requires to comply with the pitch line as explained above. However, instead of 8.5m, the building is able to be built up to 12m below the attic level. Hence, if the owner only wish to have 2-storeys, they are able to achieve a floor to floor height of 6m to achieve the luxurious high ceiling look.

Building 3 Storeys in 2-Storeys Envelope Control

“Love your 2-Storeys envelope control neighborhood but you require 3 storeys to satisfy your number of bedroom requirements”

One of the solution is to build basement for the new development. However, basement construction is costly and living in basement is not exactly pleasing.

Alternatively, a mezzanine (partial or full) can be constructed in between Level 1 and Level 2 to provide the additional bedrooms requirement. However, this will make the clear ceiling height much lower and definitely not recommended for claustrophobic individuals.

Click on below link to read up on the requirements in detail.

Step 4:

After going through step 1-3, you should have a shortlist of landed area which match your criteria. This help you to narrow down on your search. Now you have to decide on the built up area required. Based on the site plan, site coverage and setback requirement plus number of storey, you will be able to decide if unit/land is sufficient to meet your required built up area for redevelopment. Click on below link to read up on the requirements in detail.

Site Coverage:

Image Source: URA

Site coverage is calculated based on the coverage of all building features (elevated 1m or more above ground level) and footprint of the building when viewed from above.

Site Coverage = Covered Areas/Site Area

Based on above image, the area bounded by the red outline is defined as the covered area while the area in green is considered as net site area.

Site coverage is only applicable to detached houses. Based on current regulations by URA, the maximum site coverage for Good Class Bungalows (GCBs) and Non-GCBs are 40% and 50% respectively. For Semi-detached and Terraces, there is no limit on site coverage. Therefore, for the same land area, Semi-detached and Terraces will be able to have a significantly larger built-up area as compared to a detached house.

Set back line:

All developments in Singapore are required to comply to setback requirements. Setback lines is defined as the minimum distance between the land's boundary line to the respective building line. For non-GCB areas, the side and rear setback requirements are 2 meters while the road buffer depends on the category of road abutting to the unit. Hence, it is crucial to understand the category of road abutting to the unit before purchasing any land/house for development as the setback line will constraint the extent you are able to utilize your land for development.

Non-GCB Area Landed Houses

GCB Area Landed Houses

Image Source: URA

Similar to Non-GCB Area, the road buffer depends on the category of road abutting the development. However, the side and rear setback line are 3m instead of 2m.

Definition of Road Category

The below are the definitions of road category extracted from LTA.

• Category 1:

Expressway forms the primary network where all long distance traffic movements should be directed. It is planned to optimise long distance mobility from one part of the island to another.

• Category 2:

Major Arterial predominantly carries through traffic from one region to another, forming principle avenues of communication for urban traffic movements. It interconnects expressways and minor arterial as well as with other major arterial roads.

• Category 3:

Minor Arterial distributes traffic within the major residential and industrial areas. It is planned to optimise circulation within the area and facilitate through traffic between adjacent towns.

• Category 4:

Primary Access forms the link between local accesses and arterial roads. It provides access to developments and through traffic is discouraged. However, where a development is also accessible by a local access road, the access shall be located at the local access road.

• Category 5:

Local Access gives direct access to buildings and other developments and should connect only with primary access.

Step 5:

Next we will move on to check if the house or land is affected by Railway Protection requirement as this may mean that redevelopment may not be possible.

Image Source: LTA

Railway Protection Zone (RPZ) was introduced to prevent any damage to existing railway track which will result in enormous economic damage and endanger the lives of passengers. The RPZ is an area measuring 40m from the edge of the tunnel on both sides. The RPZ is further divided into 3 zones, 1st Reserve, 2nd Reserve and 3rd Reserve.

The 1st Reserve is the area measuring 6m from the edge of the tunnels on both sides. Many construction works are prohibited within the 1st Reserve. The most significant restriction is that pilings are not allowed within the 1st Reserve. This means that any redevelopment within the 1st Reserve is extremely prohibitive as intensifying the land usage will most like require stronger foundation which are usually achieved by piling. For example, redeveloping an existing one-storey terrace into three-storey terrace may be impossible within the 1st reserve especially for Kallang Formation area (Read up to find out more about different Geotechnical Formation in Singapore).

The 2nd Reserve is the area between 3m from the edge of the tunnel to the ground surface by drawing an 45 degrees line on both sides of the tunnels. There are still many restrictive activities for 2nd Reserve but piling is allowed within 2nd Reserve. However, piles which falls within the zone of influence as demarcated by the 45 degree line shall be debonded. This means that the piles are generally deeper than piles outside 2nd Reserve given the same soil conditions. Hence, due to deeper piles, the construction cost will increase due to additional material and debonding membrane.

The 3rd Reserve is between 2nd Reserve to 40m from the edge of tunnel. There are not many significant difference between 3rd Reserve and area outside of RPZ. However, submission to DBC Rail is still required and approval to be obtained before construction may commence.

In summary, it is usually more costly and time-consuming to redevelop a unit within the RPZ. It is also generally not recommended to redevelop a unit within the 1st Reserve due to the complexity

Step 6:

Next we will move on to check if the house or land affected by Road Reserve and Drainage Reserve which may require a portion of land to be vested back to the State when redevelopment or A&A is proposed to authorities. Click on below link to read up on the requirements in detail.

Road Reserve:

Image Source: Corenet

Road reserves indicate the extent of the existing or future road and its related facilities such as footpaths, cycling paths, bus-bays, covered linkways and other commuter facilities. Road reserves can be safeguarded for:

  • widening or extending existing roads; and

  • constructing future roads, e.g. expressways, arterial roads, road interchanges, traffic junctions, etc.

LTA reserves the right to acquire the land demarcated in road reserve in order for road work or road widening work to be executed.

Hence, there may be a chance that you may be purchasing a land that may require a part of the land to be vested back to the state. Furthermore, as the land is earmarked for road development, no structures above ground shall be constructed within the road reserve even though road widening or road works have not commenced.

In a scenario when there is an existing structure within the Road Reserve, it is recommended for owner not to redevelop or proceed with Addition and Alteration (A&A) for the development as the existing structure within road reserve will have to be removed which reduces the built up area.

Drainage Reserve:

Image Source: URA

A Drainage Reserve refers to land that is set aside for drainage works pursuant to development proposals approved by a competent authority. Drainage reserve shall be vested back to the state so that drainage work can be executed.

Hence, there may be a chance that you may be purchasing a land that may require a part of the land to be vested back to the state. Even if the state agree to temporarily not take back the land within drainage reserve, it will still affect the allowable built up area for detached house redevelopment.

Step 7:

We also have to confirm if there is an existing sewer located within the land/house as it will affect the redevelopment plans such as the sewer located in the middle of the house and you wish to construct a basement.

Image Source:

It is relatively common to find sewer line and manhole within a plot of land. However, the position of the manhole and sewer line is extremely important. Although, a building can be built over sewer pipes, a sewer trench is required. Depending on the length and depth of the sewer trench, the cost of the sewer trench is usually more than 30k SGD. Furthermore, the sewer trench has to have removeable panels and cannot be tiled over. Imagine having a concrete removeable panel running across your luxurious living room. Similarly for manhole, it is not able to be tiled over and will be an eye sore if it is within the living room.

Step 8:

Check on the geological formation of the house/land as your redevelopment may be affected if you wish to build a basement but the geological formation may not allow it or may be very costly.

Image Source:

Before purchasing a house or land to redevelop it, it is paramount to understand the different types of foundation for a building. There are two main types of building foundation, deep foundation like piling and shallow foundation like footing and raft. Deep foundation are usually constructed for area with weaker soil which will result in large settlement if shallow foundation is adopted. Shallow foundation is only able to be constructed on moderately strong or strong soil.

The cost of deep foundation depends on the thickness of the weak soil layer as the deep foundation requires to rest on competent soil layer. As the soil has to be relatively strong in order to construct shallow foundation, shallow foundation are usually constructed within 1 to 2m from the proposed ground level. On average, the cost difference between deep foundation and shallow foundation is around 200k SGD. Therefore, it is extremely important to understand the soil properties before purchasing any house or land for redevelopment.

Even though Singapore is a very small country, the soil varies greatly and generally are divided into 4 main types, Bukit Timah Formation, Jurong Formation, Old Alluvium and Kallang Formation.

As the name suggest, Bukit Timah Formation can be found in Bukit Timah area and also the North region of Singapore. Bukit Timah Formation is one of the strongest soil type in Singapore and is generally suitable to construct shallow foundation. However, not all Bukit Timah area has Bukit Timah Formation.

Jurong Formation are mainly found in Western Singapore and are generally relatively strong. However, Jurong Formation does not necessarily guarantee the usage of the shallow foundation. Jurong Formation also has issue of cavity if limestone is present which requires large volume of concrete to fill the void if encountered.

Old Alluvium are mainly found in Eastern Singapore and are generally relatively strong. Old Alluvium are mainly sandy soil which means they are very permeable and excavation cost may be higher as water tight excavation method are required.

Kallang Formation are mainly found in Southern and South Eastern Singapore. It mainly comprises of soft marine clay with very high water content. Deep foundation are required for buildings in Kallang Formation as the soil is very soft and weak which result in extremely large settlement to the building and its vicinity.