Celotex insulation is one of the better forms of board insulation that can be used under floors, in walls, in ceilings and in lofts. As it comes in large pieces of board, there are many ways it can be fit into lofts. Determining which way is best should be based upon the dimensions of the space you are trying to fit it into.
Cutting it Yourself
If you're trying to save money on the installation of your celotex, buy large pieces of it wholesale and then cut it yourself. Measure the areas where you want to install your celotex insulation and then buy enough boards to fill more then that space. Then use the proper tools to cut the boards apart. As these celotex pieces of insulation are rather thick, which helps it insulate so well, use a large utility knife or handsaw to cut the pieces according to the measurements you have made in the areas where the insulation is to be installed in the loft. The doorway or opening where you must fit these pieces through must also be taken into account--in order to squeeze these pieces through the door, you may have to cut some of your measured pieces in half.
Have it Cut to Size
A number of insulation suppliers will cut the insulation to exactly the sizes and shapes you need. This can be done for a cost, as they will have to take your measurements and cut all of the insulation for the loft themselves and then provide it to you prior to installation. You should also give them the dimensions of the doorway or opening you will have to fit the insulation through, so they can plan for that when doing the cutting. This is the fastest and easiest way to fit celotex boards into your loft if you have some money to spend but want the insulation to be ready and simple to install when you receive it.
Determine the Thickness of Insulation
Celotex makes its boards in varying degrees of thickness, ranging from 12mm to 200mm, providing different degrees of insulation. You should first determine the amount of thickness you want, as this will effect your total cost. Particularly if you opt for thicker boards, you may want to pay someone to cut your pieces for you so that they will easily fit into your loft.