I am building a v. large free-standing extension and rennovating an old farmhouse building with my father. We have a 'pathway' approx. 1000mm between the new building and an existing steel-frame Byre and farmhouse. The new building is to have mass concrete pier foundations with ground beams. The farmhouse has rubble/stone foundations which are not very deep. The distance between found.'s is only c.800mm. We need to take both the surface water drainage and the foul drainage (but in 2 separate pipes as it's not a combined system) underneath this 'pathway'. (It's in inverted commas as it's all mud just now!) Does anyone know if it's ok to put these 2 drains in the same trench and how far away from the found.'s they should ideally be? Should we just separate them from each other with well tamped granular material? Any guidance much appreciated - thanks!!
One trench is fine as long as you use a modern drainage system that can pass a pressure test, way back you had to install the storm higher than the foul in case of leakage.
You need at least 100mm of bedding between the two but given you will probably need inspection points/chambers it tends to be a bit more.
Check the main website and Part H Building regs with regard to excavating along the side of original shallow foundations and save yourself a lot of heartache
...tell me about it! we dug the foundation trenches for the first 15x5m 2 storey building by hand :rock: but thankfully even my dad has decided not to do that again, so the trenches for the smaller 8x5m building are getting done mechanically! phew, thank goodness for diggers! however there is still the small question of building around an ancient apple tree on the site so there will still be some punishment time to come...
