Methods of waterproofing basement walls mainly deal with the inside and outside of the wall. The best time to make sure your basement is waterproof is during construction when a waterproof membrane can be applied to the outside of the foundation. Poor original work, the home settling, or hydrostatic pressure from changes in the water table around your home could result in leaks and seepage through your basement walls. Some work is required in order to waterproof your basement walls.
First check the walls for any hairline cracks, holes, or other porous areas in the walls. With just a waterproof mix, smaller holes and cracks will be fine but larger holes will need to be filled with mortar and then waterproofed. Chisel out a dovetail to allow the mortar to properly take hold from the inside when filling in larger holes. One part cement to two parts sand with enough water to make a stiff mix makes an average mortar.
Make sure there are no air holes or pockets and use an ordinary trowel when applying mortar. To help the mortar adhere, use a stiff wire brush to get rid of loose particles before applying it because if the wall is leaking considerably you may need to put in a drainage pipe to a sub pump to help drain the water. The nature of the water flow may mean this is just temporary or it could be a permanent measure. Repair any leaking floor joints in much the same way as the larger holes in the wall.
Begin by chiselling out a dovetail joint to help it adhere and provide strength and drainage by inclining the patch slanting it from the floor to the wall. We are ready to apply the waterproof mixture after repairing the wall. The wall should be sanded to remove any paint before applying the waterproof mixture and the wall misted as the mixture does not adhere to a dry wall, but will not set on a wet wall either. The manufacturer’s instructions should be read carefully since epoxy and latex waterproofing mixtures usually require you to add some water, but you could also use your own mix of plain cement and water which should have the consistency of cream when mixed to a slurry. Begin applying the mixture with a stiff brush at the bottom of the wall moving up in a right to left direction.
Fill in all hard to reach areas. Feather the edges until the total area is covered and leave it to dry overnight or until the mixture is not sandy. Wet the wall down thoroughly once it has dried overnight and, in the same manner as the first coat was applied, apply a second coat of the waterproofing mixture. One coat will not do the job and may result in you having to start over again so always use two coats. Waterproofing basement walls is not as difficult as it might first appear if you use this information. More importantly, you will finally have that dry basement you have been wanting for so long.
