Car port to internal room

Hi not a big job at all really if the garage outer wall is only single skin. Then i would recommend this to have another skin of brick/blockwork added. This can then form a cavity to install insualtion. The floor would i imagine need to be raise depending on existing internal floor this could be concrete with insulation or a timber floor. Again same foor the joists above head. insulating.

Assuming that as it is a carport and not a garage conversion, the space has at least one if not two open sides? If this is the case then it might be necessary to excavate a trench in order to install footings so that walls can be built to enclose the area. If you wanted a cladded facade then it might be possible to build the walls in timber and potentially eliminate the need for footings depending on what ground conditions you have already. Once the new walls are up with openings left for any windows and doors, the existing walls can be insulated with a second skin, in either block work or timber. The floor level will most likely need to be raised. This can be done in either timber/insulation/chipboard or a concrete/insulation/screed build up, including any damp proofing and ventilation measures where appropriate. Other than lighting and heating, all thats left is boarding, skimming, window fitting, and flooring. All in all, a very simple job that should not take longer than a few weeks.