You might consider trying to add a new layer of ceiling drywall using GreenGlue sound proofing adheasive. This gets installed without removing anything too, it should be noted . This will be the most ... read more
We at NEWPRO have a alternate view from our industry colleague, Mr. Damora. Since the greatest concern you voiced was the lack of insulation in your extension, we recommend Vinyl Composite Siding, a ... read more