The cheapest and most effective way to dampen the noise from rain on the metal roof of your shed is by using sound-absorbing materials or insulation. Here are some cost-effective options:
Old Rugs or Blankets: If you have old rugs, blankets, or thick towels lying around, you can hang them on the interior of the shed's roof. They will help absorb and muffle the sound of raindrops hitting the metal surface.
Egg Cartons: Collect cardboard egg cartons and attach them to the roof using adhesive or staples. The textured surface of the egg cartons can help disperse and absorb sound.
Acoustic Foam Panels: Acoustic foam panels are designed to absorb sound waves. While they are more expensive than the previous options, they are still relatively affordable and can be effective in reducing noise.
Weatherstripping Tape: Applying weatherstripping tape along the edges and joints of the metal roof can help reduce vibrations and noise caused by the rain.
Insulation: If your shed is not already insulated, adding insulation to the walls and roof can help dampen noise and regulate the temperature inside the shed.
Soundproof Curtains or Moving Blankets: If you can afford a slightly higher budget, consider investing in soundproof curtains or moving blankets. These are designed to absorb and block sound effectively.
Plants or Vines: Planting vegetation around the shed or allowing vines to grow on the exterior can help absorb and diffuse sound waves, reducing the impact of rain noise.
Remember that while these methods can help reduce rain noise on the metal roof, they might not entirely eliminate it. Metal roofs can still produce some noise during heavy rainfall. If the noise is particularly bothersome and you are willing to invest more, you could explore the option of installing a secondary roof with airspace between the metal roof and the inner layer, which can act as an effective sound barrier. However, this approach would be more expensive and may require professional installation.