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What material should I use on top of footings to damp course

Anonymous user 03/03/2024 - 3.18 PM

Hi, I am getting a bay wall built at the front of my house which will be built up to the existing bay windows which are currently suspended and braced to the front wall of the house and on the inside of the house, the bay window has a big window cill / ledge / sheet of wood. We want to knock the wall out under the window and build out, following the shape of the bay window so we end up with a rectangular space inside the house under the window. Outside, were the brick wall and inner block wall will be built, my friend has dug out and we've had concrete poured in to form the foundations. But after the first few courses have gone past damp level, the void will have to be filled with something from the foundation and 3 brick courses (about 240mm) up to damp level - about 2.2m long and 460mm wide, so about 2.5 cubic metres to fill. What should I fill it with? Concrete again? How deep can sand & cement screed be filled and what is the difference between concrete and screed other than concrete is stronger? Also, I might be wrong by thinking this, but I worry that pouring concrete over some ducting means the ducting can never be got to in they bay area if there is ever a problem in that area. There was only rubble, soil and paving stones on top of a couple of the duct pipes, but now we have already poured some concrete over them. Could this ever become a problem? What material would you use for the next fill, from the concrete foundation to damp level? Your feedback and advice would be appreciated. Thank you.