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Serving NORTHERN VIRGINIA,
MARYLAND, D.C. Metro area

basement waterproofing A angieslist rating

They finished the job and had the job site cleaned up in less than a day. My wife and I were amazed!

Inadequate Grading

PROBLEM: If the ground around a foundation is level or slopes toward the house, water is directed into the basement. The soil next to the house is often backfilled without proper compaction and later settles. This is especially true under stoops where water can collect next to the basement wall.

Defective or Missing Gutters and Downspouts

PROBLEM: Missing gutters and downspouts cause rainwater to be directed toward the foundation perimeter. A downspout without an extender or splash-block is worse than no downspout at all. It is depositing the huge volume of rainwater from the roof in a single concentrated location near the basement.

waterproofing basements

Northern Virginia Basement Waterproofing
Alexandria, Arlington, Falls Church, Reston, Springfield

SOLUTION: APPROACH 1:

Install Proper Gutters and Downspouts: RECOMMENDED

Correct Grading: NOT RECOMMENDED UNLESS DONE BY PROFESSIONAL WATERPROOFING COMPANY (not landscaper or DIY)

If your home is new, less than 5 years, maybe grading and downspout extensions will help. 10-20 year old house? Call a professional Foundation Inspector. Water in the basement? It is not grading and downspout extensions. All too often, the entire solution to basement problems is misdiagnosed by a home inspector, because they do not understand this science, or they are working for the Realtor who is trying to sell a home, or both.

If water is entering the home, yes, poor grading and absence of downspout extensions may have originally played a contributing factor, 10-20 years ago. Too much water has accelerated the deterioration of you waterproofing and drainage systems. But water is getting in somehow, and usually it is because your walls are no longer waterproof, and the drainage that should be around the footing is not there, or if it is, it is not functioning effectively, most probably clogged with silt and clay or roots and gravel. Hence, water in your basement.

If you want to spend money grading, which we do not recommend, then Do Not Place Dirt Higher Against The House as this will cause water problems to flow into your first floor, and rot the following:

The Wood Sill Plate - Or Mud Plate, Which is a Pressure Treated 2X6 Or 2X8
Your Floor Joists or TGI or Wood I-Beams
Timber or Oriented Strand Board - OSB
Tieback or House Wrap

Finish grade to the first wood component of the structure should be a minimum of 18" BELOW the sill plate!

If you want to try grading as a possible solution, then first go out about ten feet from your house and start digging down. Excavate away from your house, and create a slope away from your walls, which should have been done when the house was built. If you place earth around the house, do not go up so that you are above the top of the basement wall. Make sure that it slopes away from the foundation wall a minimum of one inch per foot for at least six to ten feet. Then compact the dirt to a pan-hard surface with pneumatic or gas powered compactors.

Otherwise, you are only adding more spongy material that will soak up more water. In my 35 years, I have never seen this be effective after the fact. There is so much water in the ground, that any grading effort will actually worsen the problem as non-professionals, like landscapers, or DIY'ers do not understand soil compaction and proper grading.

Northern Virginia Basement Waterproofing

Improperly Designed Window Wells

PROBLEM: Window wells are like a drain right next to the basement wall. Often they are improperly built so that any water is directed toward, rather than away from the foundation.

SOLUTION: In a perfect world, window wells should be excavated down to the footing and a window well drain installed which will drain to the exterior drain tile system. If only an interior system exists (if not, one needs to be installed), at the very least, excavate down 2-3 feet, install a drain through the wall and then down to the interior drain system. In either case, well should be refilled with 3/8- to 3/4-inch coarse aggregate / gravel to 2 feet below the windowsill. In a situation where drain tile system is non-existent, a sump pump can be installed in the window well. For egress windows, drainage is an absolute, because you just built a mini-swimming pool, plus it is code! See Approach 2 through 7.

Northern Virginia Basement Waterproofing

Ineffective Drain Tile and Sump Pit

PROBLEM: Many existing houses simply have no subsurface drainage system. This comes from a time when basements were not used as habitable space. In other cases, the systems do not work for a variety of reasons, such as the builder didn't care or know how to install one correctly; someone who called themselves a waterproofer, was not; collapse of the pipe; clogging of the pipe with silt and/or tree roots, or a broken connection to the sump. The sump pit usually contains a pump designed to lift the water to the ground surface and discharge it outside the foundation wall. This pump can fail or may not be strong enough for the discharge line distance, or both.

We encounter these situations all the time, in homes which are old, and homes which are 2 years old. Older homes were usually built correctly, and drainpipe failure is simply a matter of time, which deteriorates almost all things. We get old, buildings get old, appliances fail; so do properly installed drainage systems from 20 to 50 years ago. Anything less should be attributed to poor construction by the original builder for improperly installing the drain tile system, i.e. - using inferior drain tile, no gravel, a cheap pump, the list goes on.

Cheap plastic pumps fail all the time. Cast iron, commercial grade Zoeller Pumps, around since 1939, are great pumps which rarely fail. I have seen them work for 35 years without failing. My first waterproofing job was an old home in Falls Church, Virginia, with a Zoeller, which was 35 years old and was still pumping out water from an old terra-cotta drain tile system, which had finally crumbled due to age.

SOLUTION: For detailed approaches on drain systems, give us a call or see the following approaches 2 through 7. These are basic designs, some good, some not recommended.

PROBLEM: Concrete and concrete block foundations usually develop some cracks. They can be severe if floor joists are not properly connected to the foundation wall, thus permitting the wall to move. Also, soil settling causes cracking. Places where walls meet rigid structures like the fireplace often crack as well. Usually, drainage removes the water from cracks, but repair may be necessary. See Concrete Crack Repair and See Approach 2

SOLUTION APPROACH 2: HIGHLY RECOMMENDED

Outside Excavation - Waterproofing and Exterior Drainage System

Installing an exterior drainage system on an existing building is the most costly, but also the most effective water control approach. This requires excavation - digging up the area around the foundation, installing a new foundation drain system, waterproofing the wall, except now we can do it with 21st Century technology. It also requires digging up shrubs and other obstacles around the house.

Usually, waterproofing and insulation are installed at the same time, in addition to making any repairs to the structure. The traditional exterior drainage systems use free-draining gravel and sand in the backfill. Drain tile must be placed beside the footing or the water level can and will reach above the floor. Level drainpipe installations are satisfactory. A minimum of 12 inches of coarse aggregate should be placed around the drain tile.

Free-draining Membrane or Board

It can be expensive to haul pea rock or sand to a site for backfilling purposes. Instead, a drainage mat can be placed against the foundation wall and then backfilled with any soil on site. The drainage must have a free-flowing path to the perforated drainpipe below.

Draining to a Sump

All exterior drainage systems must drain to gravity (usually not possible) or to a sump that can pump and discharge the water out and a few feet away.

APPROACH 3: NOT RECOMMENDED UNLESS MONOLOTHIC SLAB

Interior Drainage Channel above the Concrete Slab

In most cases when water is entering the basement, an interior drainage system is installed next to the footing under the floor (see approach 5 through 8). The most primitive, least costly, and least effective approach is a cove plate, which is a drainage channel adhered at the base of the wall and the floor slab. This is a temporary patch solution that some companies will install and charge the same amount as a professional company installing a much more comprehensive solution as illustrated in approach 5 through 8. The cost for cove plate systems should be approximately $25 a foot, although it usually isn't worth even that amount.

This solution is only recommended when outside drainage is impossible, and the foundation and floor slab are monolithic. We do not recommend this system. Sometimes this system is employed in crawl spaces that also do not have a footing. However, this is allowing the moisture into the basement interior. Water is collected and drained into a sump using another channel placed on top of the slab, then through a trap to the sump basin. It does not solve the problem in masonry walls because water remains in the block cores at floor level and the water level is only lowered to the top of the slab. With this approach, the water is not completely removed from the space. The result is that humidity, mold, and mildew can still be a problem. This system cannot drain groundwater from under the floor slab. NOT RECOMMENDED.

APPROACH 4: NOT RECOMMENDED

Interior Drainage Channel within the Slab Edge

Another low cost technique and approach, utilized primarily by Franchisee and Licensee type companies, is to place a box shaped drainage channel, with large round holes, at the base of the wall on top of the footing. This requires removing and then replacing a small amount of the concrete along the slab edge - a trench approximately 5"-7" wide and only 3"-4" deep - which is the average thickness of most floor slabs. The drainage channel is connected to a drainpipe leading to the sump.

Serious Drawbacks

This is a "cookie-cutter" approach that requires little training or experience, and would not pass a county inspection. It is not ‘up to code' - county and municipal codes, and engineering standards, require 4" Perforated Drain Tile, installed in gravel, next to the footing, not in the floor slab. These systems should not cost more than $25 per linear foot since there is one-third the labor and material cost compared to a properly installed drain tile system.

Moreover, the size of these box shape drains is not sufficient to handle large volumes of water. These systems have different shapes and prices depending on the Franchised or Licensed product installed. Also,they have no flexibility, which means they cannot go around corners, or around obstructions, or around pipes, which may sit next to the wall, or around the 90? corner which all basements have.

The worst feature of this system is the 1" or 2" of concrete that is replaced back over top of this flexible plastic pipe. This is a flexible plastic which has no compressive strength. This flooring will not last very long as it is not the required 4" of concrete that is minimal code, and any attempt to finish your basement, i.e., nailing a base plate on top will crack the ‘new' cement, and will just not adhere - there isn't sufficient concrete. Also, no gravel. A real interior or exterior drain system consists of 4" pipe, alongside the footing, below the floor depth, surrounded by gravel, which in and of itself, also acts as a drainage system. Again, NOT RECOMMENDED!

APPROACH 5: RECOMMENDED

Interior Drainage System Beneath the Slab

One of the most effective of the interior drainage systems is a 4" perforated drainpipe installed inside the perimeter of the footing, in a wide, sloped, trench, with round washed gravel completely surrounding the drain tile.. This requires removing and replacing approximately 12"- 18" of concrete at the slab edge. By placing the drainpipe beneath the slab, it drains the area to a lower level.

Almost as effective as an exterior system, the interior drainage pipe connects to a sump, which discharges the water outside. A critical component of this approach is the dimpled plastic sheeting (Miradrain® 2000R)placed at the base of the wall and beneath the slab edge. Dimpled sheeting is similar to a small egg crate and permits free drainage of the wall into the drainpipe. It is less expensive than many specialized drainage channel systems. In low permeability soils, which is exactly what we have in the MD / VA / DC Metro area, this system cannot accept rising groundwater unless there is a sufficient aggregate layer under the slab (round washed gravel).

APPROACH 6: RECOMMENDED

NEW RESIDENTIAL CONSTRUCTION

When a new home is being constructed, this is the time to properly install drainage systems inside and outside, to properly waterproof the walls from the outside with rubber type elastomeric membranes, modern day drain mats, to backfill with a gravel / sand mixture, and to install an interior wall system that is water and mold proof. Although basements are usually not designed to be waterproof, Apex Waterproofing can and does design waterproof basements. We do it all the time!

Call or email now! We're always available for a free consultation! (800) 656-4604.