Exhibit 21

GEORGIA GULF CORPORATION  SubsidiariesAs of February 28, 2008

|    |  | Company Name                                                                                 |  | Jurisdiction of Incorporation
|--- |  | -------------------------------------------------------------------------------------------- |  | -----------------------------
|1.  |  | Georgia Gulf Corporation                                                                     |  | Delaware                     
|2.  |  | 1299239 Ontario Limited [HoldCo.]                                                            |  | Ontario                      
|3.  |  | 6630987 Canada Inc. [Vaughan East]                                                           |  | Canada                       
|4.  |  | 6632149 Canada Inc.                                                                          |  | Canada                       
|5.  |  | Advanced Profiles, S.A. de C.V.                                                              |  | Mexico                       
|6.  |  | Bluegrass Products, LLC                                                                      |  | Delaware                     
|7.  |  | Dartmouth Extrusions Limited                                                                 |  | Ontario                      
|8.  |  | Edificacion Tecnica Internacional S.A. de C.V.                                               |  | Mexico                       
|9.  |  | Georgia Gulf Chemicals & Vinyls, LLC                                                         |  | Delaware                     
|10. |  | Georgia Gulf Europe, ApS                                                                     |  | Copenhagen, Denmark          
|11. |  | Georgia Gulf Lake Charles, LLC                                                               |  | Delaware                     
|12. |  | GGRC Corporation                                                                             |  | Delaware                     
|13. |  | Great River Oil & Gas Corporation (Acquired by Georgia Gulf Corporation on July 25, 1980)    |  | Delaware                     
|14. |  | Plant # 12 ((f.k.a) Royal Sierra Extrusions, Inc)                                            |  | Washington                   
|15. |  | Plant # 13 ((f.k.a.) Custom Window Extrusions))                                              |  | Pennsylvania                 
|16. |  | Plant # 14 ((f.k.a.) King Extrusions)                                                        |  | Nevada                       
|17. |  | Kolorbond International Limited                                                              |  | United Kingdom               
|18. |  | Le-Ron Plastics Inc.                                                                         |  | British Columbia             
|19. |  | Novo Capital, Inc.                                                                           |  | Nevada                       
|20. |  | Novo Management Inc.                                                                         |  | Nevada                       
|21. |  | PHH Monomers, LLCMembers                                                                     |  | Louisiana                    
|22. |  | Plastic Trends, Inc.                                                                         |  | Michigan                     
|23. |  | RBS (U.S.A.) Limited                                                                         |  | Delaware                     
|24. |  | Rome Acquisition Holding Corp.                                                               |  | Nova Scotia ULC              
|25. |  | Rome Delaware Corporation                                                                    |  | Delaware                     
|26. |  | Royal Buildings Products, a division of Royal Mouldings Limited (Newbern Tennessee Division) |  | Nevada                       
|27. |  | Royal Group Mexico S.A.de C.V.                                                               |  | Mexico                       
|28. |  | Royal Group Sales (USA) Limited                                                              |  | Nevada                       
|29. |  | Royal Group, Inc.                                                                            |  | Canada                       
|30. |  | Royal Mouldings Limited                                                                      |  | Nevada                       
|31. |  | Royal Outdoor Products, Inc.                                                                 |  | Indiana                      
|32. |  | Royal Plastics Group (U.S.A.) Limited                                                        |  | Delaware                     
|33. |  | Royal Railings, LLC                                                                          |  | Pennsylvania                 
|34. |  | Royal Building Systems De Mexico, S.A. de C.V.                                               |  | Mexico                       
|35. |  | Royal Ventures Construction & Development, Inc.(in the process of being sold)                |  | Philippines                  
|36. |  | Royal Ventures Land Holdings Corp.(in the process of being sold)                             |  | Philippines                  
|37. |  | Royal Vinylbilt Limited                                                                      |  | Ontario                      
|38. |  | Royal Window Coverings (USA) L.P.                                                            |  | Texas                        
|39. |  | Royalguard, Inc. (Shell Co.)                                                                 |  | Delaware                     
|40. |  | Roybridge Financing Trust                                                                    |  | Quebec                       
|41. |  | RoyCom Limited                                                                               |  | Manitoba                     
|42. |  | Vinyl Solutions, LLC                                                                         |  | Delaware                     

---



QuickLinks