The cement pad is fairly simple, but very important. Also it will be much easier if you do things in the correct order.
1- Figure out the size of your pad. To Do this, You will need to know the dimentions of the wood boiler, then make sure the pad is large enough to fit the wood boilder, and also provide enought room to build the walls for the shed, and fit insulation. You will also want to provide enough room on the back to run blumbing, electrical, etc.
2- Find a location for the pad. In finding a location for your pad, consider putting it as close to the house as possible, without risking the house catching on fire due to sparks from the chimney. If you plan on putting it close to the house (not only close to the house, but close to a location on the house where you can run your water lines in), you may need to put a tall chimney to raise above the hight of the house. Check local codes to make sure you are do this correctly. However also remember that the further away from the house your boiler is located, the more heat loss you will get from pumping the water through the cold ground (even though they will be well insulated). You also want to make sure the location is close to where you will store your wood, so you don't have to haul it too far.
3- Make a lever area where you plan on making the cement pad. You will want to make this area the size you want your pad, plus enough room to add forms. Make sure when you level the area you only remove soil, don't put any new soil in to rais one side. If you need to raise one side use gravel. If you add soil, it may settle after you pour your pad, which will cause your pad to crack, or become uneven.
4- Run Underground water and power lines. To do this, you will need to figure out where you can run your lines into your house. I had was able to cut a hole just above my foundation, and run the plumbing, and electrical lines through it. You will need at least 5 water lines:
- A Feed line going from your boiler to your heating source for your house (in floor heat, radiator, etc). If you have a large house, you may need several of these. I ran one 3/4" line, and can t it in my house to feed more heating sources If I need to.
- A return for for each feed line
- Two lines for the hot water heater circualation (feed and return)
- A top off line to keep your boiler water topped off.
To insulate these lines, an wrapped each one in foam insulations, and put them in a 4 inch black flexible drain pipe:
For the power, I ran a 2" pvc pip undergroud, and into my house, so I can run the electrical wires through when I am ready.
I buried the elecrical pipe, and insulated water lines about 2 feet underground (the deeper the better up to 5 feet). One end goes into the house, and the other end comes up through where the pad will be (in the back, behind where the boiler will sit.
5- Form and pour the pad. Now that everything is ready, form up and pour your cement pad, just make sure it is big enough, and you have all your underground plumbing in place. Also make sure the ground is solid, level and flat. I made my pad the thickness of a 2×4 (3 1/2").