Here are some hacks to fix your leaky roof easily.
Check for unusual water clogging above your ceiling. In case you live in an apartment, check for leakages in the apartment above yours. If you have a terrace above your roof, ensure you have water-proofed it.
Get rid of dust and debris on the floor and fill the cracks and crevices with mortar or roof cement. Follow through by applying a roof primer. Wait for it to completely dry out and spread an elastomeric sealant over the cracks, holes, corners, and other damaged areas.
Schedule maintenance and leakage check-ups at least twice a year. Apart from the usual inspections, get a thorough check-up done by a professional.
Install a concrete, commercial roof as it is highly durable, weather-resistant and cost effective too.
You can apply the second coating the next day to reinforce the sealant.