If you have a concrete block window well in your home, whether it is being used to capture the ends of a sash cord or to hold soil away from the window, it is partially below the ground. You can build a well using concrete blocks or create one from a steel window well which has been pre-built. If you need to re-add the concrete block due to soil being moved or after a frost has cracked the concrete, then you need some basic gardening tools, concrete blocks, and a few spare hours to perform the task.
Step 1 - Digging out the Old Window Well
The first step is to remove the old window well. Do this simply by digging behind the concrete blocks that form the well until you have removed all but the last layer. Take some chicken wire and use it to hold up the soil while you remove the final layers in order to prevent it coming down upon you.
If necessary, shore up the dirt with wooden planks until you are ready. Use a drill to remove the masonry fasteners that hold the last concrete blocks onto the asphalt or concrete path below. Once you have removed the old window well, check that the pavement to which it is attached is completely intact or lay new pavement before adding the replacement window well.
Step 2 - Fitting the First Layer
Using your tape measure, work out the length and depth of each of the concrete blocks. Choose regularly shaped blocks. Lay each block flat against the floor, ensuring that it props the soil behind it. Screw these blocks into position and tighten them. Ensure that these blocks are level before you add the next layer.
Step 3 - Build the Window Well
Take the cement and add a layer over your first blocks. Allow the cement to get slightly tacky, then install the next row of blocks. Ensure that each is level and even. Repeat this until you have built the blocks high enough to support the soil. They should be slightly taller than the soil in order to protect the window against heavy rainfall.
Step 4 - Finishing
Once you have finished installing the blocks, you can cover the area with asphalt mastic. It will allow you to place a metal or wooden frame over the top of the concrete blocks, giving them additional support. You should allow the cement and the mastic to dry in position, then backfill or leave the path as it is. In order to prevent the ground from collecting dirt or being flooded by trapped snow, you should add a roof or a plastic hood to the top of your window well.