Air Well Renovation
Cover It, Enclose It or Keep It Open? (2026)

What an air well actually does

An air well is the open gap inside the footprint of a terrace, semi-D or older shophouse-style home, open to the sky, usually near the stair or between the front and back halves of the house. It brings daylight into rooms that have no outside wall, lets hot air rise out of the middle of the house, and lets rain fall onto a small drained floor instead of into the rooms.

ClickBina's terrace house interior design guide calls the air well the biggest asset in a terrace house, if it has one: opened up, glazed over with a skylight, or planted as an internal courtyard. The question for most owners is not whether the air well is useful, but how to keep its light and air without living with its rain, leaves and insects.

Why owners want to change it

• Rain and splash: heavy rain blows in and wets the floor, the walls and anything near the opening.
• Leaves, dust and birds: the open top collects debris that blocks the floor drain.
• Mosquitoes: a poorly drained floor holds standing water after every storm.
• Security: an air well reachable from a roof or back lane is a way into the house.
• Wasted floor space: in a small terrace the air well can look like a room that is never used.
• Leaks: old junctions between the air-well walls and the roofs around it let water into the ceilings.

ClickBina's burglar-proofing checklist lists an air well among the things a person standing in a shared back lane might reach, alongside drying yards and low roofs, which is why many covers include a grille or a fixed top.

The three routes compared

Covering it: skylight or polycarbonate roof

Most owners choose to cover the air well and keep it as a light well. The two common materials are polycarbonate sheet and glass. ClickBina's polycarbonate roofing guide lists air-well covers among the usual uses of the material, because it is light, lets daylight through and is cheaper than glass. Glass looks clearer and lasts longer but needs a stronger frame.

The detail that matters most is ventilation. A sealed lid over an air well traps the hot air that used to escape, and the middle of the house warms up. Options that keep some airflow include a raised roof with a gap or louvres on the sides, a vented skylight, or a cover that stops short of the full opening. ClickBina's guide to a skylight that is too hot explains the order of fixes if a cover already makes the room uncomfortable: shade it, film it, let the hot air out, then upgrade the glazing.

Enclosing it as a room: approvals and the rooms next door

Turning the air well into floor space, for example a bigger kitchen, a dining area or a study, changes the building, not just its finishes. Treat it like an extension: an architect or draughtsman checks the plans, the council decides whether approval is needed, and any new floor slab or roof structure is designed by an engineer.

The air well may also be how the rooms beside it meet the building by-laws. ClickBina's store room conversion guide quotes By-law 39 of the Uniform Building By-Laws 1984: every room used for residential purposes needs natural lighting and ventilation through windows of not less than 10 percent of the clear floor area. Close the air well, and a bedroom or kitchen whose only window faced it may no longer meet that rule.

Drainage and waterproofing at the junction

Whatever you choose, water has to go somewhere. An open air well needs a floor that falls to a working drain sized for a storm, and a raised step or upstand so water does not run into the rooms. A covered air well moves the problem up: the roof must shed water into a gutter or onto the main roof without pouring onto the walls, and the junction between the new cover and the old walls needs proper flashing.

ClickBina's skylight cost guide is clear about this: a properly sealed install with aluminium flashing, liquid membrane and weep channels adds RM500–RM2,000, and it is what prevents leaks. Ask any contractor exactly how the junction will be sealed before you accept a quote.

What the main options cost

ClickBina publishes these figures on its skylight and polycarbonate guides. The air well's size, the height of the opening and the access for scaffolding move a job within each range:

Ideas that keep the air well useful

• Planted court: pebbles, a few shade-tolerant plants and a glass sliding door turn it into a view from the dining area.
• Light well over the stair: a skylight above, an open-riser stair and a light wall spread daylight through two floors.
• Drying court: a covered, ventilated air well near the kitchen becomes a sheltered drying area.
• Small water feature: only with a proper drain and a pump, or it becomes a mosquito pond.

How to decide, step by step

1. Note which rooms get their only daylight or window from the air well.
2. Watch it in a heavy storm: where the water goes, and whether the drain keeps up.
3. Decide what you need most: less rain, more security, more floor space, or more light.
4. If you want floor space, ask an architect or draughtsman about approval and By-law 39 first.
5. If you want a cover, choose polycarbonate or glass and insist on a ventilation gap and proper flashing.
6. Get the cover, the drain and any grille quoted together so one contractor answers for the junction.

How ClickBina can help

ClickBina is an experienced KL & Selangor contractor for roofing, renovation and whole-house refurbishment, so the cover, the drainage, the grille and the finishes around an air well can be planned as one job. WhatsApp us your job details for a quote: the area, the property type and the rough size of the air well. We reply within the hour, and the price we agree is a flat price with no hidden charges.

Sources & methodology

• ClickBina skylight cost guide — skylight types, installed prices and the flashing and membrane detail.
• ClickBina polycarbonate roofing guide — air-well covers and per-metre-run prices.
• ClickBina hot skylight guide — solar-control coating prices and the order of fixes.
• ClickBina store room conversion guide — By-law 39 of the Uniform Building By-Laws 1984.
• ClickBina terrace house interior design and burglar-proofing guides — the air well's role and security.

How we estimated prices: every figure is quoted unchanged from the ClickBina guide named beside it; they are indicative Klang Valley ranges, not a quotation. This page is general information, not architectural or legal advice.