| ING./TAKSTMANN ASLE THOMASSEN | 980231135 | SORTLAND |
| ING. TAULE AS | 988103381 | ALVER |
| ING. TRYGVE JENSEN AS | 997019466 | ARENDAL |
| INGVALD ROGNALDSEN AS MURMESTERFORRETNING | 932092050 | BERGEN |
| ING. VIDAR NILSEN AS | 915183964 | ALTA |
| INJEKSJONSTEKNIKK AS | 957688020 | OSLO |
| INKA ENTREPRENØR AS | 982714737 | OSLO |
| INNEKLIMAXPERTEN - BKM AS | 913136276 | KRISTIANSAND |
| INNHAVET TRANSPORT AS | 972409979 | HAMARØY |
| INNHERRED ANLEGG OG UTEMILJØ AS | 931072951 | INDERØY |
| INNHERRED ENTREPRENØR AS | 916761856 | LEVANGER |
| INNLANDET BYGGETEKNIKK AS | 927585952 | GAUSDAL |
| INNLANDET ELEKTRO AS | 925732567 | HAMAR |
| INNLANDET ENTREPRENØRSUPPORT AS | 923704523 | NORD-AURDAL |
| INNLANDET FLIS & MUR AS | 925794813 | GJØVIK |
| INNLANDET GEOTEKNIKK AS | 924789778 | KONGSVINGER |
| INNLANDET LANDSKAPSUTFORMING AS | 916818122 | LILLEHAMMER |
| INNLANDET TAKSTFORRETNING AS | 929007751 | RINGSAKER |
| INNLANDET TAKTEKKING AS | 931996835 | RINGSAKER |
| INNLANDET TRE & BETONG AS | 999311709 | SØR-ODAL |
| INNLANDSCONSULT AS | 986469028 | HAMAR |
| INNMÅLINGSTJENESTER AS | 979927703 | BERGEN |
| INNOMHUS AS | 985806063 | BERGEN |
| INNORE AS | 819337772 | LILLESTRØM |
| INNOVA BYGG AS | 858529972 | BÆRUM |
| INNTRE KJELDSTAD AS | 986044019 | STEINKJER |
| INNVÆR MUR & BETONG AS | 923084851 | VINDAFJORD |
| INOR AS | 986594124 | TROMSØ |
| INRIGO AS | 921474431 | TRONDHEIM |
| INSENTI AS | 996043851 | OSLO |
| IN SITU AS | 992355212 | MOSS |
| INSTALL AS | 911853914 | LIER |
| INSTALLATØRENE AS | 997781694 | OSLO |
| INSTALLATØREN FREDRIKSTAD AS | 912645177 | FREDRIKSTAD |
| INSTALLATØR PER ØVERLAND AS | 919811714 | PORSGRUNN |
| INSTALLATØR STIG LIND AS | 875971832 | ØKSNES |
| INSTANES AS RÅDGIVENDE INGENIØRER | 934485378 | BERGEN |
| INSTANT VVS AS | 916914067 | LILLESTRØM |
| INSTA RØR&REHAB AS | 930831492 | VESTBY |
| INTEC NORGE ØST AS | 928429032 | OSLO |
| INTERIØRFAGHUSET T. LUND AS | 820500482 | STAVANGER |
| INTERNO BYGG & INTERIØR AS | 922885621 | OSLO |
| INTER RØR AS | 932559331 | SULA |
| INTO ELEKTRO AS | 859028012 | KVINNHERAD |
| INTO RØYR AS | 990977631 | KVINNHERAD |
| INVENT AS | 986464352 | BERGEN |
| IPEC MILJØ AS | 935235618 | BIRKENES |
| IPOA AS | 997039297 | MOSS |
| IR BETONGARBEID AS | 913194020 | SIRDAL |
| IRBYGG ENTREPRENØR AS | 920405746 | OSLO |