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Additions and Alterations (A&A)

premium addition and alteration (a&a)
works in singapore

Welcome to Haus Atelier, the leading provider of Additions and Alterations (A&A) works in Singapore. Our team has a passion for creating functional, beautiful living spaces that always meet and even exceed our clients' expectations. Whether you’re looking to add more living space, update the layout of an existing room, or completely transform your home, we have the expertise and resources to make it happen!

A&A stands for 'Additions & Alterations’ to a building. As the name suggests, it denotes derivations to the existing building involving significant changes ( but not more than 50%) to either one of the following:

  1. Gross Floor Area

  2. External Walls ( Facade)

  3. Structure

  4. Replacement of Roof without involving an additional storey

  5. Addition of Attic ( provided GFA is less than 50%)

As a BCA licensed GB1 builder, we are fully equipped to handle the necessary applications and approvals from the necessary Authorities. Trust us to deliver the best A&A works that money can buy and create a beautiful, functional space that exceeds your expectations.

what is addition and alteration(a&a) works?

why experience matters in
addition and alterations works

As a landed homeowner, you may be eager to get started on your renovation or addition in Singapore. However, it's important to take the time to carefully consider your plans and make informed decisions. That's where an experienced company like Haus Atelier comes in. Houses are at the forefront of our business - and we have a team that is trained in Design, Architecture and Structure coupled with the knowledge of local compliances and requirements to aid in your process.

We can help you navigate the often grey and unusual process, ask the right questions, work with the necessary experts, and explore different scenarios to ensure you are making the best possible choices for your home improvements and alterations.

a&a works vs reconstruction:
what's the difference?

Additions & alterations (A&A) works involve minor modifications to an existing landed house, while reconstruction involves replacing a “substantial” portion of the house, either by increasing the gross floor area, replacing or constructing new external walls, or replacing or constructing new structural elements.


What's the Difference between A&A and Reconstruction

Generally, if the proposed works exceed 50% of any of the following factors, they will be considered reconstruction:

  • Gross floor area: the amount of new floor space compared to the existing space

  • External walls: replacing or constructing new walls

  • Structural elements: replacing or constructing new columns, beams, or floor slabs

In addition to these criterias, any work involving an adidtion of a new level is always considered reconstruction, regardless of the percentage of the existing structure that is being replaced.

common a&a works in singapore

A&A Works refer to Additions and Alterations to an existing building. The scope of A&A work can be simple or exhaustive; it's all dependent on the scope and extent of the addition and/or alteration. More often than not, the extent of A&A is largely dependent on the strength of the existing structure.

For example, your living room has a double-volume space and you decided to slab over the double-volume space to extend the L2 floor plate.  That can be a simple A&A if the existing structure is able to take the extension and a bondek slab can be erected over the void. If the existing structure is incapable of withstanding the new loading, then construction of new columns on footing may be involved. The latter being more invasive to the existing structural grid.


Our expert structural engineers are the best people to determine the extent and exhaustiveness of such a scope.

What are the most common A&A projects in Singapore?

Swimming Pools

  • Standalone properties with enough space and budget may add or edit the shape of swimming pool.


  • Changes to the location and type of staircase ( ie. from dog leg staircase to spiral etc)

  • Changes to the type of stairs are also part of A&A - ie. Changing a closed riser staircase to an open riser one.

Extension of Floor Plate

  • A common desire is to extend the existing 2nd Storey floor plate to its maximum boundary

  • Such an extension, while possible, can be quite major depending on the size of the extension and dependent on whether the existing structure is able to take the load.


  • Adding an attic can provide extra space and height to homes, depending on each home and the existing roof levels of these homes - an attic may or may not be allowed depending on whether the existing structure is already at the maximum of its building envelope. 

  • Attic construction is also expensive and may not be possible for all homes due to structural limitations.

 Addition of Lifts

  • Lifts usually require a lift pit and sometimes a lift overrun. The addition of a lift definitely adds mobility and flexibility for the owners but would involve a change in the structural grid of the house.

  • The addition of a lift can fall into the category of A&A if there is space for a lift shaft and a hydraulic lift can be added.

  • To add a traction lift (the lifts that we are accustomed to) often falls in the realm of reconstruction.

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