Anyone

Building a conservatory is a massive undertaking – It is, for all practicle purposes, adding an addition to your home. Based on your question it seems that you are doing all of the work yourself. The concrete foundation will be the most important part of you conservatory so there are some basic guidelines to follow before you get to work:
First you want to make sure that you are working on completely level ground. You achieve this by first grating the surface by hand and then level it off by a moving weighted method. If you do not have access to a mini bulldozer then you can do it manually by using a wooden pallet (like the ones used at the grocery store) weighted down with heavy rocks or even people standing on it. The best way to pull the pallet is with a tractor or a sit down mower. Once you have the land leveled then you need to figure out what size, shape and depth of concrete slab you will require. If you are using a pre-fabricated conservatory kit then you will need to follow the measurement directions in the book that comes with it. If you are erecting a conservatory of your own design than you will need to find the precise area of the base of the conservatory, add four inches to all sides, and then stake out the area on the ground. Once you have the area staked out, spray paint lines on the ground in a bright color connecting the stakes. Next, with pieces of 4X8’s or longer pieces of wood planks, box in the staked off area. If you are boxing in a very large area then you will need to divide it up into 3 to 4 sections at a time. Next, fill the area with a very thin layer of quality concrete base gravel. Make sure you leave around three inches from the base of the gravel to the top of the wood. Next, using a quality concrete such as QuickCrete, mix batches as designated on the bag. Work in sections by filling the boxed off areas smoothing with a hand trowel. Allow a section to set before removing the wood plank. Work on the next section, moving the plank divider and joining each section, smoothing over joints as you go. Make sure you allow each section to set. Once every section is finished, leveled, and smooth allow it to set and dry completely. You are now ready to begin erecting your conservatory ontop of the cement slab foundation.
Good Luck – It can be difficult, but fun and certainly rewarding!
Hope this Helped!