Question
My homes ventilation vents are in the second row,from the ground, of the concrete block foundation. There is a trench around the foundation from when the footing was poured, and the land is 5 inches up from the bottom of the first row of concrete blocks. If I fill this trench with dirt it will cause the vents to be level with the land. I would like to know if I need to slope the yard away from the house or can the trench be filled with a coarse rock, such as river rock, to provide adequate drainage of rain water away from the foundation and seeping under the house.

Answer
Hi Stephen,

Ok, I would recommend that you firstly lay a nylon fabric (the kind that you'll find in a builder's merchants) over the area that you wish to raise. This will seperate the gravel from the soil and prevent it clogging with soil (Important!). Then fill and raise the area around the house with large rock (over 2inches diameter)and then cover that area with another piece of nylon fabric for the same reason. You can then place some soil over the gravel, without fear of it mixing and clogging.

However, in order to grow grass you will need to have around 25 inches of soil or else will just dry up.

Hope that's been helpful

Jonathan (www.ecologicagardens.com)