Joints Visible in Plasterboard Ceiling and all the edges look cracked

If you do decide to tackle the job yourself, you'll need to follow these steps: 1. Clean the surface: Before starting, make sure the surface is clean and free of debris. Use a damp cloth to wipe down the surface and remove any dust or dirt. 2. Tape the joints: Apply joint tape over the plasterboard joints using a taping knife, making sure to press the tape firmly into place. 3. Apply joint compound: Use a wide taping knife to apply a thin layer of joint compound over the entire surface of the ceiling, covering the joint tape and filling in any gaps or cracks. Allow the compound to dry completely. 4. Sand the surface: Once the compound is dry, use a sanding block or sandpaper to smooth out any rough or uneven spots on the surface. 5. Apply a second coat: Apply a second, thinner coat of joint compound over the entire surface of the ceiling, feathering the edges out to create a smooth, even finish. Allow the compound to dry completely before sanding again. 6. Finish and paint: Once the surface is completely smooth and even, you can finish and paint the ceiling as desired. Overall, while it is possible to do this job yourself, it can be a difficult and time-consuming process, so it may be best to hire a professional if you're not confident in your abilities. A professional will have the tools and experience necessary to create a smooth and seamless finish, ensuring that your ceiling looks great for years to come.

It's possible that the boards weren't secured well enough when they were installed, or there has been movement in the house which has caused them to sag. It's also possible the original plasterer didn't use Scrim tape on the joints of the boards, leaving them visible. Checking that the boards are secured properly and then applying Scrim tape to any visible cracks and board joints before a Re-skim will fix the problem.

Always best to get a professional in as it's normally above what the customer has in skills and tools

If the plasterer boards have been put up with a hammer and clout nails as they were before battery drills came along . Then over time the boards will drop on the nail causing the cracks where the boards meet . I personally would insert screws either side of the cracks thus lifting the boards back up. Then cut out the crack with a Stanley knife and fill over all cracks and where the screws have been inserted. Then rub down and paint.