Boss Facts & Tips

Classic Block Wall Foundation Seepage

blockwall cross sectionThis cross section diagram depicts typical block wall water infiltration…

As your home ages it’s not uncommon for the exterior tar application to wear off or break down, just like the shingles on your roof do. When this happens ground source water can penetrate through the porous block and migrate down through the hollow cavities. It then seeps out from the bottom block/s onto your floor.

Ground source water can also wick up through the cove joint between the block wall and poured slab when there is an overwhelming volume of water in any one area around the footing or under the slab.

New exterior waterproofing applications and interior water control methods can resolve these issues. See our services pop down menu for more information.

Where’s the Water Coming From?

Typical at grade & below grade causes of infiltration…

When water is present in your basement it sometimes leaves you puzzled as to how it got there.

Take a look at some of the more typical routes of infiltration. Keep in mind that water can show up in your basement through above grade opportunities as well, it’s all due to gravity!

A leaky front door threshold, deteriorating chimney, aging shingles or improper downspout drainage are just a few examples.

wheres the water coming from revised


  1. 1. Water seeps in through the block wall, fills up the cavities & bleeds out at the bottom block onto your floor
  2. 2. Cracked or deteriorating mortar joints can allow ground source water to penetrate into the blocks
  3. 3. Seepage can penetrate around any pipe joints not properly sealed in block wall or poured wall constructions
  4. 4. Water can seep over the top of the foundation wall for various reasons
  5. 5. Plugged window drains and/or aging windows can lead to seepage around the perimeter of the window
  6. 6. Active poured wall foundation cracks will direct water into the basement
  7. 7. Blocked or partially blocked weeping tile can overwhelm the footing area & seep in
  8. 8. Exposed form tie rods can rust allowing water to seep in
  9. 9. Water presenting along the wall can sometimes be a direct result of cove joints problems
  10. 10. Floor drains without backflow preventers can allow water to rise back up
  11. 11. Deteriorating sump pits can cause seepage as well as faulty sump pumps
  12. 12. Hydrostatic pressure under the floor can create floor cracks & the pressure can push the high water table up through the floor