How to Waterproofing Basement Walls

There are a number of ways of waterproofing basement walls, mostly dealing 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. Reasons for leaks and seepage through your basement walls include poor original work, the home settling, or hydrostatic pressure from changes in the water table around your home. It is possible to waterproof your basement walls with some work.

Any hairline cracks, holes, or other porous areas in them should be identified. 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. When filling in larger holes a dovetail should be chiseled out to allow the mortar to properly take hold from the inside. An average mortar is enough water to make a stiff mix with one part cement to two parts sand.

No air holes or pockets should be present and an ordinary trowel should be used to apply the mortar. It a good idea to use a stiff wire brush to get rid of loose particles before applying the mortar to help it adhere 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. This arrangement may be temporary or permanent according to the nature of the water flow. Leaking floor joints and larger holes in the wall should be repaired in much the same way.

Help it adhere by chiselling out a dovetail joint and make sure to incline the patch slanting it from the floor to the wall to provide strength and drainage. Once the wall has been repaired it is time to apply the waterproof mixture. Sand the wall to remove any paint, mist the wall then apply the waterproof mixture while the wall is not dry but is not so wet that it will not set. Be sure to read the manufacturer's instructions carefully as epoxy and latex waterproofing mixtures usually require the addition of some water, or alternatively you may use your own mix of plain cement and water and this should be mixed to a slurry about the consistency of cream. Use a stiff brush to apply the mixture at the bottom of the wall and move up in a right to left direction.

Make sure to get it into every crook and crevice. The edges should be feathered until the whole area is covered then leave to dry overnight or as long as the mixture takes to become firm. The next morning, wet the wall down thoroughly again and apply a second coat of the waterproofing mixture in the same manner as the first. 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. Better yet, you will finally have that dry basement you have been wanting for quite some time.