I'll catch you on the download!
The Winx Clubhouse was an old warehouse that Musa was given ownership of after Sifelius could not do anything to stop the demolition plans the city had for the pavilion he lent her. It is exclusively featured within the Winx Club Comic Series, making its debut in Issue 80: Old Doors New Mysteries.
The building is surrounded by a chain fence with a large silver gate as the entrance to the front gardens, which have grown erratically to the point where it resembles a forest. As for the building itself, it is cream in color with orange accents, large glass windows (all of which have been shattered), a large brown doorway, and a brown roof with windows adorning it. There are four large orange spires at each corner of the warehouse and it appears to contain at least two stories. There is also a smaller shed-like building just at the back of the warehouse that possesses a similar design. Due to all the surrounding plant life growing uncontrolled for so long, most of the outer walls are covered in vines and moss.
When the warehouse is seen again in Issue 84, it has been repaired and has been used as a personal clubhouse by the Winx since the end of Issue 80. A major section of it was reserved as a rehearsal station of fledgling musicians to keep up with Musa's business.
Now that it has been repaired from the inside-out, the Clubhouse's exterior is no longer covered in moss, vines, cracks, or peeling paint. There is even an added section of the left side (most likely the shed that was merged to the building) and the odd crown-shaped structure has been removed. The plant life has also been cut down, making it look more like a normal albeit expansive front yard with a few trees. All moss and vines have also been removed from the fence and gate.