Natalie Mansfield, 30, was stripping the wallpaper of her house when she found a mural depicting warfare involving planes and ships.
The building itself dates back to 1935, but it is unknown whether the painting was done at around the same time or later on.
Upon posting the images of the discovery to a Facebook group, she received over 800 reactions and a plethora of supportive messages from other group members who praised the find.
One remarked: “What a lovely find, it must have looked impressive when it was first painted. It’s a shame to paint over it!”
Another guessed that it portrayed World War Two conflict over the Mediterranean owing to the good weather in the drawing.
But how and why it was painted remains unknown, as well as where the mural is set.