Renovating a flat in a Mumbai housing society.

A renovation in a Mumbai cooperative housing society is a shared project, whether you like it or not. The building, the lift, the staircase and the flat below all take part.

The good news is that almost every problem can be prevented with a little planning. This is the order in which we work through it with the families we design for.

Start with your society's rules

Most housing societies ask members to apply in writing before carrying out repairs or alterations, and many attach conditions to their approval. Ask the secretary or manager for the society's renovation rules before you finalise your designer or your dates. Look for:

• The application format. Some societies have a standard form; others accept a letter with a description of the work and a drawing.
• Working hours. Noisy work is usually limited to daytime hours on working days, and often not allowed on Sundays and public holidays.
• A refundable deposit. Some societies ask for one against damage to common areas.
• Lift and staircase use. Rules on carrying material in the lift, protecting it, and the times when it can be used.
• Debris disposal. Where debris can be stored and how quickly it must leave the premises.
• Worker details. Some buildings ask for a list of workers and identity documents for security.

Know what you cannot change

Some parts of your flat belong, in effect, to the whole building. Changing them can weaken the structure or affect other homes, and is either not allowed or needs professional sign-off and formal approvals.

• Columns, beams and structural walls. Never cut, chase deeply or remove them. Many newer towers are built with load-bearing concrete walls throughout, so a wall that looks like a partition may be structural.
• Moving wet areas. Relocating a bathroom or kitchen over a bedroom in the flat below creates a real leakage risk, and many societies will not permit it.
• The facade. Enclosing a balcony or changing windows and grilles on the outside of the building is usually controlled by the society and the municipal rules.

If any structural change is on your wish list, ask for a structural engineer's opinion first and check with the society which approvals are needed. A good designer will tell you early when something is not possible, and suggest another way to get the same result.

Protect the flat below

Leaks into the home below are the most common cause of disputes during and after a renovation. If you are replacing a bathroom floor, the old waterproofing will be disturbed, so plan to redo it properly.

1. Remove the old flooring down to the base slab and repair any cracks.
2. Apply a fresh waterproofing layer, taking it up the walls and around every pipe.
3. Before tiling, flood the floor with water and leave it for a day or two. Check the ceiling of the flat below with your neighbour.
4. Only tile once the test is dry. Use epoxy grout in wet areas.

The same care applies to kitchen sinks, washing machine points and balcony drains.

Bring your neighbours along

Your neighbours will live with the noise and dust for weeks. A few courtesies make an enormous difference:

• Let the flats next to, above and below yours know before work begins, with the expected duration.
• Share your site manager's phone number so they can call someone other than you.
• Tell them in advance about the noisiest days, such as tile removal or core cutting.
• Protect the lift and corridor floors, and keep common areas clean every day.

Plan around the monsoon

Mumbai's monsoon, roughly June to September, changes what can be done well. Anything that involves the outside of your flat, such as window frames, external wall repairs, balcony waterproofing or new grilles, is best finished before the rains arrive.

Interior carpentry can continue through the monsoon, but paint, polish and adhesives take longer to dry in humid air. Build that into the schedule rather than rushing finishes. Our guide to monsoon-proof interiors covers the materials that cope best.

Keep the paperwork

Keep one folder, physical or digital, with everything related to the work:

• The society's permission letter and any conditions.
• Your quotation, contract, drawings and schedule.
• Photographs of common areas taken before work starts.
• Warranty documents and the care notes for your finishes.

If a question comes up in a year, about a leak, a deposit or a hinge, you will have the answer in minutes.

Checklist

• Collect the society's renovation rules and application format.
• Confirm working hours, holidays and lift timings.
• Check whether a deposit is needed and how it is returned.
• Confirm with your designer that no structural element is affected.
• Plan bathroom waterproofing and a flood test before tiling.
• Inform neighbours and share the site manager's number.
• Schedule outside work before June.
• Photograph common areas before work begins.
• Keep every document in one folder.

This guide is general advice from our experience of working in Mumbai buildings. Rules vary between societies, so always confirm with your own society and, for structural questions, a qualified engineer.