Condenser on common property: approval before, not after
An outdoor unit serves one household, and installing it is rarely a private act. Fixing it to the building, or standing it outside your walls, brings the corporation's permission into the job. Owners generally find that out from a letter, long after the work.
By Team Snowflake | Updated 7 Aug 2026
Why a private machine becomes an estate matter
The machine is yours, and the act of putting it up often is not. Three things reach past your own walls at the same moment. Something has to hold the unit, and those fixings land in the building. The unit has to stand somewhere, and that somewhere may sit beyond the lot. The block looks different from the road afterwards, and the outside of a building is a shared face.
BCA's guidance on carrying out works in lots deals with a close cousin of this. An owner wants a covering, and the anchor points for it mount onto the external wall. The stated answer is that the work unavoidably uses common property, so the owner has to obtain the corporation's approval for those works on it. A condenser bracket does the same thing to the same wall.
Two questions come before this one, and both are answered elsewhere. The MCST guide covers the corporation itself, its council, and the source of its authority. The aircon ledge guide covers whether the platform under your condenser falls inside your lot. Everything below starts once that boundary answer is in, including the common outcome where nobody at the office is certain.
None of this reaches an HDB block, where there is no management corporation to approve anything.
Approval is not one thing, and the names differ
BCA sets out separate routes for works inside a lot, and they are not interchangeable. Which one a job lands on turns on what the work does. It does not turn on how large the job feels from the inside. A single condenser install can land on more than one route at once.
The first route is whatever your own estate has written down. A corporation may make by-laws requiring an owner to meet stated requirements and to obtain its approval before carrying out works in a lot. Architectural guidelines made that way can fix design, colour, material, size and dimension. Those requirements can also extend to a professional engineer's endorsement on structural works, and to clearances from outside bodies covering planning, fire safety and building control.
The second route opens when the work cannot avoid using common property. BCA's position is that the owner has to obtain approval from the corporation to carry out such works there. That permission is separate from the one your by-laws ask for. A job can satisfy the estate's renovation form and still need it.
The third route uses a heavier word, and it is the one owners miss. Where proposed works will affect the appearance and structural integrity of the buildings, the owner is required to obtain authorisation from the corporation before those works are carried out. BCA says approval for the first two routes and authorisation for this one. The change of word is worth noticing before assuming a stamped form has covered everything.
The fourth route is the outer edge and a condenser rarely reaches it. Where works will affect the gross floor area of the development, BCA states that the corporation's authorisation comes through a ninety per cent resolution at a general meeting. It defines that as owners holding at least ninety per cent of the aggregate share value of those present in person or by proxy voting in favour. Enclosing a ledge or building a new platform is where a job begins to approach this. Hanging a replacement on brackets that already exist is a long way off.
| What the work actually does | What has to be obtained | What the requirement attaches to |
|---|---|---|
| What the work actually doesAnything the estate's own rules already cover | What has to be obtainedThe corporation's approval under its by-laws | What the requirement attaches toBy-laws and architectural guidelines the estate made |
| What the work actually doesUses common property because it cannot be avoided | What has to be obtainedApproval for those works on the common property | What the requirement attaches toThe shared part being used or fixed into |
| What the work actually doesAffects the appearance and structural integrity | What has to be obtainedAuthorisation, obtained before the works start | What the requirement attaches toHow the buildings look and how they stand up |
| What the work actually doesChanges the development's gross floor area | What has to be obtainedAuthorisation, via a ninety per cent resolution | What the requirement attaches toFloor area across the whole development |
Does a stamped renovation form settle it?
A processed renovation form proves a form was processed. Whether it carries the permission your works needed is a second question, and the office is the only place to ask it. Two sentences answer it. Which requirement was the form issued under, and does anything in the scope touch shared structure or the outside of the building.
If the answer to the second is yes, ask for written confirmation that the shared part is covered by the same document. An office that has thought about it will say so readily. One that has not will now go and check, and prompting that check is the whole reason to ask early.
Where a condenser job crosses, and how often
Count the crossings before booking anyone. A condenser install usually makes three of them, and each can return a different answer. The fixings go into something. The machine stands on something. The result is visible from outside.
Fixings are the crossing owners think least about. BCA treats structural elements such as slabs, beams, columns and walls as common property. Its guidance is that these must not be altered without proper assessment by a professional engineer and approval by the corporation. For localised chasing and drilling on structural elements, it asks for a competent renovation contractor and a professional engineer's advice that no strengthening is needed and structural integrity will not be affected. Clearance from the corporation comes before the work starts, not after.
Visibility is the crossing that catches replacements. A unit in a new position, a wider casing, or a bracket where a floor stand used to sit all change what the facade shows. An estate with architectural guidelines has already decided part of this in advance. Reading them is faster than proposing something and waiting for a council meeting.
Four adjacent decisions belong on other pages. How much space the machine needs around it belongs to condenser clearance. Where it can sensibly go belongs to outdoor unit placement. What it must not do at a neighbour's boundary belongs to the NEA noise guide. Reaching a high ledge safely is planned under the work at heights guide, and a managed estate will usually add conditions of its own on that.
Does a like-for-like replacement count as works?
The office will ask what changes, so work that out before asking anything. A swap that keeps the same position, the same fixing points and a similar footprint is a different proposition from one that shifts the machine, adds anchors or grows the profile.
Where nothing about the fixings or the position moves, put that in writing and ask the office to confirm it reads the job the same way. Where something does move, the routes above reopen and it is cheaper to know that at quotation than at the gate.
Why time in place leaves the question open
Approval is something that happens first, and elapsed time does not perform it for you. Every route in BCA's guidance is written the same way. Prior to the works. Before such works are carried out. Nothing in that framing turns a long-standing installation into an approved one, and equipment can sit unremarked for a very long stretch with no record behind it.
Retrospective letters arrive for ordinary reasons rather than dramatic ones. A managing agent changes and the incoming firm compiles a register. A facade inspection or a repainting cycle puts somebody on the ledge with a clipboard. A neighbour asks about a noise and the office looks at the position. The unit is sold and the buyer's solicitor asks what the outdoor unit is bolted to.
The letter lands at the unit rather than with whoever did the work. An installer who packed up long ago is not the party the office writes to, and the person holding the lot now is the one reading it. Settling it at installation is cheaper for exactly that reason. The contractor is still on site, and the scope can still be redrawn.
A useful reply establishes what exists instead of arguing about how long it has stood there. Ask the office to search its own records for any approval naming these works. Ask what it would want to see now. Take that answer in writing whichever way it goes, because a spoken all-clear leaves nothing on file for the next person to find.
What to obtain, and where to keep it
Ask for the approval as a document that names things. A letter saying approved, with no mention of the works, the position or the fixings, is hard to use later. The later question is always whether the equipment now standing there is the equipment that was permitted.
Ask which route each requirement travelled. An office that can point at the by-law, the guideline or the shared part being used is giving you something checkable. One that cannot is describing a practice, and practices move when staff move. Neither answer is a problem at the point of asking, and both are worth having.
Ask what closes each condition. Conditions attach to most approvals, and the ones to pin down are those with evidence behind them, such as a professional engineer's endorsement or a photographic record of the surface once it is reinstated. Agreeing what counts as satisfied is easier before the work than during the inspection afterwards.
Keep the file with the unit rather than with the job. The next owner inherits the equipment and the question attached to it, and a folder that travels with the flat answers a solicitor's query without anyone reconstructing events. A photo buried in a chat thread is not a file.
- The written approval itself, naming the works, the position of the unit and how it is fixed down
- Which requirement each condition came from, stated in the office's own words
- Any professional engineer's endorsement obtained for fixings landing in structural elements
- What the office accepted as evidence that each condition had been met
- The date, the officer and the reference number, so the same file answers the question when it is asked again
Where this page stops
Neighbouring questions have their own pages, and this one leans on them. The MCST guide sets out the corporation and the range of things it may ask for. The aircon ledge guide takes the lot boundary, along with exclusive use by-laws and the limits on what they change. The condo installation checklist carries the forms, the timing and the order they go in. Equipment serving lobbies and function rooms is condo common-area aircon, and the corporation buys that work itself. Late faults in a brand new development belong to the condo defects window.
Behind all of this sits a single statute, now titled Building (Strata Management) Act 2004. The old name, Building Maintenance and Strata Management, survives as BMSMA across most search results. Reading it will not tell you what your own estate requires of you. Two locally held documents govern that: the by-laws lodged for your strata title plan, and the plan itself. Where real money or a removal is at stake, put both in front of somebody qualified to read them against your situation, rather than working from a general page.
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