I am digging some holes in my garden for some 150mm posts for some decking supports. I have just come across the main soil pipe running through the garden which one of the corner posts needs to go. Can i span a lintel across the pipe and if so what do i need to do. The soil pipe is about 600mm below and the hole so far is about 500mm square.
Yes you can Simon. Excavate either side of the pipe and lay two foundations of 6 to 1 mix concrete (see our mixing concrete project) which are 500mm long, 300mm wide and 150mm deep. Lay 100mm concrete blocks on their side on each foundation keeping the blocks in the middle of the "pads" Lay the blocks to 150mm above the top of the pipe and then bed 3 150mm (wide) x 75mm lintels over the pipes. The lintes should have at least 150mm sitting on each pier.