An unusual problem... initially it looked as though there was a gap - possibly caused by movement - between the hardboard panel and the ceiling / wall. This wasn't quite the case though as when smoothing out the acrylic filler the panel shifted inwards even more making the gap even wider.

 

The cause of the shift was that the panel was only secured at one end - the other end having no support naturally gave way under the slightest pressure.

 

The Remedy

 

1. Drill a small hole in the panel

 

2. Insert a screw or awl and tighten

 

3. Pull the panel back out

 

4. Apply acrylic filler from gun as normal then smooth out while pulling the panel towards you

 

5. Leave to set

 

  

   

Gap gets wider as caulk is applied

 

 

       

         

Insert screw or awl and pull towards you 

 

 

          

 

Finished look!