Knowing Your Type of Foundation Will Help With Basement Waterproofing

See the vertical crack, it's 1.5 feet over from the corner and next to that gutter downspout.  This type of crack will follow the block mortar joint all the way to the basement floor and follow a stair-step pattern.

This is very typical of a block foundation wall, settling usually occurs in the corners and very small movement down will create these cracks that go from the ceiling to the floor.

A drain tile system could be installed to help with this issue but it would be running all the time when it rained.  It wouldn't help prevent water damage to the outside side of the block since it's just managing the water and not stopping it.  In fact it might make matters worse over time.

Our experience  tells us that voids will develop around this crack, the sand and soil will also drain inside the blocks creating the growing voids next to the foundation.  Now water from the downspout fills up the voids during rain storms and it makes it 's way into the wet basement as a faster rate.

Stopping water outside of the foundation is Real Waterproofing, the water voids will be filled and the water pathways will be blocked with bentonite, stopping the water from moving through your walls.

Poured walls, are constructed by using a wooden (sometimes metal) form on each side, and concrete is poured down the middle. The form keeps the wet concrete from spreading out. Newer style forms are made using styrofoam blocks, just like Legos, stacked up to the proper height, they stay on the dry concrete when it's back-filled providing some insulation value.  

Older style wood and metal forms are reusable but they typically use sacrificial metal tie-rods to hold them together so "blow-out" doesn't occur.  The forms are cleaned with water and taken to the next job site. 

Part of the tie-rod (the rusted square in the middle of the photo) is left in the concrete when the concrete drys, the ends are hammered off.  

These walls will develop holes when the tie-rods rust through or they will get stress cracks near the tie rods or form seams.

The metal tie-rods left in the walls sometimes rust through, leaving a hole 1/4" x 2," big enough for a lot of water.  It's also above the underfloor drain tile system so it never makes it to the sump pump.  If this area had been finished, the drywall, trim and insulation would have been removed to expose the basement water leak.

This basement has a drain-tile system under the floor but the leak is around 20" above the floor where the crusty minerals are.  This leak is flowing water when it rains.

These types of basement water are easy for us to stop on the outside, most of the other companies will recommend ripping out your working drain tile system and putting up plastic sheets or dimple board to waterproof this wall but it's not really waterproofing.  Stopping water on the outside is waterproofing, letting it through the wall is water-management.