Q: How Does Water Get Into My Foundation?

A: At DriTek Solutions, we know that you may be wondering how does water enter a foundation? There are 4 ways that moisture enters your basement, crawl space or slab foundation. They are:

  • Capillary action – water wicks through porous materials or small cracks. Poured concrete walls and concrete blocks are porous materials used to build foundations and foundation walls. Primary sources of moisture through capillary action are rain and groundwater.

    Figure 1. An example of capillary action Photo source

  • Bulk water transport – moisture flows through holes, cracks or gaps in foundations and foundation walls. Primary sources of bulk water are rain and groundwater.

    Figure 2. example of bulk water transport

  • Air transport – unsealed cracks, holes, and joints between conditioned and unconditioned areas allow air containing water vapor in the air and soil. Primary sources are water vapor in the air and soil.

    Figure 3. how moisture is transported through the air and soil

  • Vapor diffusion – water vapor in the air moves through permeable materials Primary source are water vapor in the air.

    Figure 4. example of vapor diffusion (condensation)

It’s easy to see obvious signs of a water intrusion problem in a foundation, whether they are basements, crawl spaces, or slabs.

Most foundation and below-grade walls are constructed from poured concrete or concrete masonry block. Concrete products are porous and, unless treated, are not waterproof, allowing water to migrate into the building.

Common signs of moisture problems in existing foundations can be seen as visible water or puddles, visible staining of interior finishes, mold growth, and efflorescence (water-borne white mineral salt deposits). Interior finishes or insulation may conceal the presence of bulk water issues for extended periods of time, and problems may not be evident until damage is extensive.

Groundwater and rainwater can cause a lot of damage to a home. Building materials that are allowed to remain damp or saturated for long periods of time will eventually fail.

Foundation water barrier systems help drain water away from the slab, footing, and below-grade walls. What this means to you is peace-of-mind knowing your home has a comprehensive set of measures that minimize the risk of water damage in your basement. Wouldn’t you agree every home should have full water protection?

At DriTek Solutions, we understand how water enters your foundation. We are experts at finding solutions to your water intrusion problem. We are the best choice for basement waterproofing, drainage solutions, foundation repair, and crawl space encapsulation.


Q : What are the best practices for waterproofing a foundation?

A: You might be thinking: This is all new to me and I’m not expert – what are the best practices for waterproofing my foundation? You’ve come to the right place. We ARE the experts at waterproofing your foundation in the Atlanta, GA area.

Interestingly, if you do some research you’ll find that building scientists recommend the following practices (outlined for you below) to waterproof your foundation and keep the water out. We’ve yet to come across any research that states that the best solution is bringing the water inside your foundation so that you can then, in turn, manage it and pump it back outside. Learn more about the difference between waterproofing and water management here.

WATER INTRUSION IN A HOUSE OR BUILDING

Groundwater and rainwater can cause a lot of damage to a home. Building materials that are allowed to remain damp or saturated for long periods of time will eventually fail.

Figure 1. example of water intrusion in a basement

Water management is an important part of the design and construction of a house or building. Keeping water from entering is critical to ensure the long-term structural integrity of the building as well as to reduce the chances of mold issues and poor indoor air quality. A complete water management strategy will deflect water that comes in contact with the building envelope and divert that water down and away from the house.

Foundation water barrier systems help drain water away from the slab, footing, and below-grade walls. What this means to you is peace-of-mind knowing your home has a comprehensive set of measures that minimize the risk of water damage in your basement. Wouldn’t you agree every home should have full water protection?

FOUNDATION BASICS

Slabs, crawlspaces, and basements are all common foundation types in the mixed-humid climate, which is the type of climate we have here in Atlanta, GA. Slabs can be monolithic or poured inside stem walls on footers. The foundation forms the solid underpinning for a house’s structural integrity. It also provides the boundary between the house and the ground, preventing the unwanted transfer of moisture, air, heat, and soil gases from the ground to occupied living spaces. It plays an important role in building durability and occupant health as well as in building energy efficiency.

CONTROLLING LIQUID WATER IN FOUNDATIONS

Most foundation water leakage or intrusion is due to either bulk moisture leaks or capillary action. Bulk moisture is the flow of liquid water. Capillary action occurs when water wicks or is absorbed into small cracks and pores in building materials, such as masonry block, concrete, or wood. Moisture can also be carried by soil gas into the home. Regardless of the source, moisture can cause structural decay and can contribute to health problems.

First, proper site grading directs surface water away from building foundations and walls. The steeper the slope away from the building, the better the water will drain.

Figure 2. Proper building drainage

All building foundations should be designed and constructed to prevent the entry of moisture. In most foundations, the dominant source of moisture is bulk water. Bulk water enters because of improper irrigation practices, ground slope, rain runoff, high groundwater tables, and rain during the construction process. These sources can be controlled by careful site grading, installation of drainage systems, proper foundation design and waterproofing, appropriate landscaping, and other measures.

Figure 3. Proper site drainage

RECOMMENDED PRACTICES FOR WATERPROOFING FOUNDATIONS PROPERLY:

  • Design the house structure with overhangs, gutters, drainage planes, and flashing to shed rainwater and conduct it away from the house [as required in 2009 and 2012 IRC R703.1 and R703.8].
  • Slope top soil to drain away from the house. [2009 and 2012 IRC R401.3 require that the lot be graded to fall at least 6 inches in the first 10 feet from the foundation.] Building America recommends a surface grade of at least 5% for at least 10 feet around and away from the entire structure.
  • Drain driveways, garage slabs, patios, stoops, and walkways away from the structure. [2009 and 2012 IRC R401.3 require that impervious surfaces within 10 feet of the building foundation be sloped at least 2% away from the building.]
  • Keep all untreated wood away from contact with earth and concrete. Keep wood and fiber cement siding at least 8 inches from the soil surface to minimize damage from rain splashing up from the ground surface.
  • Install a protective shield between the foundation wall stem and sill plate to keep water from wicking into the wall from the foundation.
  • Damp-proof or water-proof all below-grade portions of the exterior concrete foundation walls [2009 and 2012 IRC R406].
  • Cover exposed earth in crawl space floors with 20-mil polyethylene sheeting. All joints of the vapor retarder shall overlap by 6 inches and be sealed or taped. The edges of the vapor retarder shall extend up the stem walls and columns to 4" below the floor joists above. [The 2009 IECC 402.2.9 and 2012 IECC 402.2.10 and the 2009 and 2012 IRC 408.3 require a vapor retarder over exposed earth in unvented crawl spaces.]
  • Damp proof the exposed portion of the foundation.
  • Place a continuous drainage plane or free-draining materials over the damp proofing or exterior insulation on foundation walls to channel water to the foundation drain and relieve hydrostatic pressure. Drainage plane materials include impervious plastic mats, high-density fiberglass foam insulation boards, and uniformly graded gravel.
  • Place slabs and crawl space floors above the surrounding grade.
  • Treat footings poured independent of slabs or foundation walls to isolate the footing from the remainder of the assembly.
  • Place 6-mil polyethylene sheeting or rigid foam insulation directly beneath the slab or basement floor. Wrap sheeting continuously under the slab and footings up to grade.
  • Do not place a sand layer between the vapor retarder and the concrete slab or basement floor. Differential drying and cracking is better handled with a low water-to-concrete ratio and wetted burlap covering during initial curing.
  • Place a 4-inch-deep, ¾-inch gravel bed directly beneath the polyethylene sheeting to act as a capillary break and drainage pad.
  • Ensure that the lowest excavated site foundation level is above the local groundwater table at its maximum elevation [per 2009 and 2012 IRC R408.6].
  • Install a perimeter drain below the drainage plane along the side (not on top of) footings for all basements and crawl spaces where the floor is below grade.

Figure 4. Proper Foundation Waterproofing at Initial Build

A damp-proof coating can be applied directly to the surface of the concrete below-grade walls. Other steps can be taken to ensure water does not sit against the foundation wall. In addition to proper grading and installation of gutters and downspouts, the soil around the foundation should consist of a free-draining layer of backfill material or plastic dimple drainage mat can be installed against the foundation wall. This should direct groundwater downward to a perimeter drain. The perimeter drain should be located exterior of the footing and should be wrapped in crushed rock and landscape fabric. A crushed stone drainage layer under the basement slab can be connected to this perimeter drain. A capillary break should be installed between the footing and the foundation wall to stop rising damp from happening.

Waterproofing the surface of below-grade walls is only one small part of a whole-house water management strategy and should be conducted in conjunction with other good site management practices including site grading, a footing drainage system, gutters and downspouts, and water-resistant wall and roof construction techniques.

Other water management steps include grading the site so ground surfaces slope away from the foundation, using a house design that includes deep roof overhangs, installing a foundation drainage system, and installing gutters and downspouts that drain water away from the house.

RETROFITTING EXISTING HOMES

In an existing home, it is possible that no footing drain pipe was installed around the foundation of the home. If one was installed, it may have been installed improperly or it has since gotten clogged with dirt or roots or broken by landscaping or other excavation activities. Indicators of a missing, clogged, or broken drain pipe include water collecting in the basement or crawlspace.

However, water in the basement or crawlspace could also be due to other factors. While cleaning out, installing, or replacing blocked footing drain pipe around the foundation may solve the problem, it is a labor-intensive fix that involves excavating around the home’s perimeter, ideally to the footing. Before undertaking the expense of drain pipe replacement, a homeowner should confirm that:

  • gutters and downspouts are installed and operating correctly
  • there are no plumbing leaks in the basement or crawlspace
  • there are no gaps or cracks in the basement or crawlspace wall that are providing a pathway for water
  • the final grade slopes away from foundation
  • patios, sidewalks, and driveways slope away from the house or drains are installed to collect and carry water away from the house

After checking and correcting anything needed on the above list, if there is still elevated foundation moisture present, you will want to excavate and install drain tile (perforated plastic drainage pipe) as low as possible along the basement or crawl space walls to provide drainage around the foundation.

To carry water away from the foundation, a footing drain system should be installed consisting of a perforated drain pipe (also called a drain tile) that is located underground on the exterior side of the footings at a depth below the level of the basement slab or crawlspace floor. The perforations allow any surface or groundwater that reaches the footing to flow into the drain tile and be carried away rather than pooling along the foundation wall.

To keep the pipe from getting clogged with silt, the pipe is wrapped with filter fabric and then laid in a bed of washed stone that is also wrapped in filter fabric, also landscape fabric. The pipe surrounds the full perimeter of the house and is laid so that it is slightly sloped, allowing water entering anywhere along the perimeter to drain to a single collection point. That collection point connects to an unperforated pipe that discharges the drain pipe to an above-grade location at least 10 feet away from the foundation or to a suitable alternative such as to a basin, well. or storm sewer (if allowed).

A properly installed and functioning footing drain system will keep water moving away from the foundation to help maintain a dry basement or crawlspace. Poor installation of the pipe system often prevents it from accomplishing this important drainage function.

In order to ensure the drainage system is installed properly, it is important that only clean gravel be used in the trench around the drain tile. Gravel that has sand or silt will foul the perforations in the drain tile and eventually diminish the system’s ability to divert water away from the foundation.

DRAINAGE

A well-sealed foundation or crawl space will keep water from entering the home, but to finish the task of waterproofing, you must also create a path for water to flow away from the home and be discharged at a safe distance. Allowing water to collect around the foundation will eventually lead to unacceptable levels of soil saturation and ultimately could negate any water sealing practices used to protect the foundation. Learn more about the best practices for drainage and grading here.

To carry water away from the foundation, a footing drain system should be installed consisting of a perforated drain pipe (also called drain tile) that is located underground on the exterior side of the footings at a depth below the level of the basement slab or crawlspace floor. The perforations allow any surface or groundwater that reaches the footing to flow into the drain tile and be carried away rather than pooling along the foundation wall. To keep the pipe from getting clogged with silt, the pipe is wrapped with filter fabric and then laid in a bed of washed stone that is also wrapped in filter fabric, also landscape fabric. The pipe surrounds the full perimeter of the house and is laid so that it is slightly sloped, allowing water entering anywhere along the perimeter to drain to a single collection point. That collection point connects to an unperforated pipe that discharges the drain pipe to an above-grade location at least 10 feet away from the foundation or to a suitable alternative such as to a basin, well. or storm sewer (if allowed).

A properly installed and functioning footing drain system will keep water moving away from the foundation to help maintain a dry basement or crawlspace. Poor installation of the pipe system often prevents it from accomplishing this important drainage function.

In order to ensure the drainage system is installed properly, it is important that only clean gravel be used in the trench around the drain tile. Gravel that has sand or silt will foul the perforations in the drain tile and eventually diminish the system’s ability to divert water away from the foundation.

At DriTek Solutions, we understand how water enters your foundation. We are experts at finding solutions to your water intrusion problem. We are the best choice for foundation waterproofing, drainage solutions, foundation repair, and crawl space encapsulation.


Q: What are the best practices for drainage and grading?

A: You may have questions about drainage and grading and at DriTek Solutions, we are here to help. We are experts at foundation waterproofing, foundation repair, drainage and grading in the Atlanta, GA area. Below you’ll find answers to your questions regarding the best practices for drainage and grading to minimize water intrusion issues for homes and buildings.

GRADE SLOPES

The best defense against water intrusion through the foundation is to prevent water from saturating the soil around the foundation. This can be done by constructing the foundation and grading the site so that water drains away from the house on all sides.

Figure 1. Proper Building Drainage

Figure 2. Proper Site Drainage

The final grade around the house slopes away from the foundation. Proper selection of backfill soils, filter fabric-covered footing drains set in gravel, and a capillary break protect the home’s foundation from water intrusion.


HOW A SITE SHOULD BE GRADED DURING INITIAL CONSTRUCTION
  1. Grade to build up the site before construction, if needed, to create a slope that will carry water down and away from the foundation on all four sides.
  2. After construction, backfill to the foundation walls, grade the slope, cap the top layer of the grade with 2 to 4 inches of silty clay, and mechanically compact the soils to prevent later settling.

The 2009, 2012, and 2015 International Residential Code (IRC) requires impervious surfaces within 10 feet of the building’s foundation to have a slope of 2% away from the foundation. ENERGY STAR Certified Homes requires a final grade slope of  ≥ 0.5 inch per foot away from home for ≥ 10 feet. ENERGY STAR also states:

  • Tamping of the backfill is not required if either: proper drainage can be achieved using non-settling compact soils, as determined by a certified hydrologist, soil scientist, or engineer; OR, the builder has scheduled a site visit to provide infill and final grading after settling has occurred (e.g., after the first rainy season).
  • If setbacks limit the space on any side of the home to less than 10 feet, or if walls, slopes or other physical barriers prevent the construction of slopes away from the foundation, then install either swales or perimeter drains designed to carry water away from the foundation.

SWALES

A swale is a channel that is dug to receive storm water overflow, allowing it a path to flow away from the home. Swales can provide a way to slow water runoff and allow natural draining into the soil on the site. They are typically located along property boundaries along a natural grade.

They will also draw in water that would otherwise sit in a flat yard and they can divert water flowing toward the house from an upward sloping yard. Swales are typically planted with specific types of vegetation to reduce erosion, to help remove any pollutants found in the storm water runoff, and to improve the beauty of the design.


DRAINS

Another alternative for bulk water management is drains. Drains can be installed to collect and direct surface water away from the foundation. Metal grated drains can be installed at the base of driveways that slope toward the house. Perforated drain pipe can be buried in rock-filled trenches upslope from the house. These drains can be piped to carry water runoff underground to a basin or well, storm sewer (is allowed), or another approved discharge point.

RETROFITTING EXISTING HOMES AND BUILDINGS

Once a home has been constructed and concrete driveways and patios are poured, it is sometimes a difficult and expensive process to regrade the site should water issues arise due to a negative slope on one or more sides of the home. Other options for dealing with water that wants to flow toward the house are to install footing drains, if they don’t currently exist, and to install waterproofing on the exterior surface of the below-grade walls. Swales or other drainage systems can be also be installed.

Drains can be installed at the base of driveways and patios that slope toward the house. Solid-surface driveways, patios, and walkways can be replaced with pervious surfaces such as pavers, gravel, or pebbles, to allow water to drain into the ground rather than flowing toward the house. Sometimes a combination of measures is needed to keep the basement or crawlspace dry.

GUTTERS AND DOWNSPOUTS

A few inches of rain falling on the roof of a house can produce several thousand gallons of water runoff. This runoff must be channeled away from the building foundation to keep the basement or crawlspace dry and to prevent water from seeping into the building interior where it may create moisture problems. If not drained away from the house, the immense volume of water coming off the roof can quickly saturate the soil surrounding the building and wick through the foundation to the interior. Once inside, this moisture can lead to a variety of problems, including mold and rot. Moisture in homes is both a cause of indoor air quality problems and an important factor affecting the durability of the structure.

As a whole-house best practice, it is important to design the house exterior with climate-appropriate flashing, overhangs, gutters, downspouts, and drainage planes to shed rainwater and conduct it away from the house. Here in Atlanta, GA we live in a mixed-humid climate. You can learn more about our climate and its requirements here. A system of gutters and downspouts is particularly important to keep water away from the building foundation in areas with expansive soils, such as here in Atlanta, GA and the surrounding areas.

Expansive soils swell when they get wet and can put extreme pressure on foundations, even to the point of causing cracking or uplift of foundation materials. At the very least, when these soils get wet around a building, they can create a trough that collects water, increasing the likelihood of that water seeping into the foundation.

CONTROLLING ROOF RUNOFF

Contractors have four options for dealing with rain water runoff from a roof:

  • Install gutters and downspouts that terminate at least 5 feet away from foundations. OR
  • Install gutters and downspouts that terminate to an underground catchment system at least 10 feet away from foundations. OR
  • An alternative option to gutters is to deposit rainwater to a grade-level rock bed with a waterproof liner and a drain pipe where water terminates on a sloping finish grade at least 5 feet from the foundation. OR
  • If a rainwater harvesting system is installed, properly design the drain to adequately manage the overflow and meet discharge-distance requirements.

In addition, gutters and downspouts need to be sized to accommodate anticipated water loads. The number of downspouts will depend on the cross-section dimension of the downspout material. There should be 1 square inch of downspout cross-section for every 100 square feet of roof area. Downspouts should be at least 20 feet apart but no more than 50 feet apart.

These are the best practices for drainage and grading to minimize water intrusion issues for homes and buildings. If you are in need of solutions for drainage and grading, at DriTek Solutions, we can help. We are experts at drainage and grading and how  that impacts water entering your foundation. We are experts at finding solutions to your water intrusion problem. We are the best choice for foundation waterproofing, drainage solutions, foundation repair, and crawl space encapsulation.


Q: Why should I encapsulate my crawl space?

A: THE IMPORTANCE OF CRAWL SPACE ENCAPSULATION


Figure 1. A properly encapsulated a crawl space

We know that your home is the most important investment that you make, and you care about not only your house structure and possessions, but also the people inside. So let’s get into a bit of detail about why you would want to encapsulate your crawl space.

There are 4 ways that moisture can enter your crawl space: Capillary action, bulk moisture transport, air transport, and vapor diffusion. You can learn more about those ways here. It’s usually easy to see obvious signs of a water intrusion problem in a foundation, whether they are basements, crawl spaces, or slabs.

In vented crawl spaces, the dominant source of moisture is bulk water, not water vapor from indoor or outdoor air condensing in the crawlspace. Water enters the crawlspace because of improper irrigation practices, ground slope, rain runoff, high groundwater tables, rain during the construction process, and leaks in plumbing.

Figure 2. Bulk water in a crawl space

These sources can be controlled by careful site grading, installation of drainage systems, proper foundation design and waterproofing, appropriate landscaping, and other measures. Most foundation water leakage or intrusion is due to either bulk moisture leaks or capillary action. Bulk moisture is the flow of liquid water. Capillary action occurs when water wicks or is absorbed into small cracks and pores in building materials, such as masonry block, concrete, or wood. Moisture can also be carried by soil gas into the home. Moisture may cause structural decay and can contribute to human health problems.

But water in its liquid state is not the only problem that houses can face. Water vapor can also be a source of damage. Unlike moisture in its liquid form, water vapor travels wherever air flows. Where there are air leaks, there are vapor leaks. Diffusion can also force vapor through materials and into places it shouldn’t be, such as wall cavities. Differences in vapor pressure and temperature are the forces that drive diffusion. Vapor diffusion moves moisture from areas of higher vapor pressure to areas of lower vapor pressure, and from areas of higher temperature to areas of lower temperature. Air movement is by far the most important mechanism for moving water vapor.

Water vapor causes problems when it is trapped within a building assembly, such as a wall cavity. When warm air touches a cold surface, the water vapor it carries can condense, turning into its liquid form, where it can cause damage to structural components. Condensation can also form in and on ductwork, especially when air conditioning cools duct surfaces that come in contact with humid air, such as in a vented attic or crawlspace.

Figure 3. Condensation on floor joists in a crawl space

Vapor movement through a building component can be impeded by use of a vapor diffusion retarder (vapor barrier). Some moisture in crawl spaces also occurs from soil vapor. To control water vapor from soil vapor in crawl spaces, it’s important to do the following:

  • Install 20-mil polyethylene across the entire ground surface.
  • Overlap all seams by 12 inches and tape.
  • Seal Vapor barrier to the wall with caulk sealant to 4" below floor joists above or at least above outside grade level.

Figure 4. A diagram of properly installed vapor retarder

Sealed, conditioned crawl spaces offer non-energy advantages over vented crawl spaces that are worth considering, such as minimizing bulk water intrusion and pest intrusion.

MOISTURE CONTROL STRATEGIES IN CRAWL SPACES

Before you decide on a moisture control strategy, it helps to understand that moisture or water vapor moves in and out of a home in three ways:

  • With air currents
  • By diffusion through materials
  • By heat transfer.

Of these three ways, air movement accounts for more than 98% of all water vapor movement in houses and buildings. Air naturally moves from high-pressure areas to lower pressure areas by the path of least resistance, and generally that air moves through any available hole or crack in the home or building. And moisture transfer by air movement happens quickly. Carefully and permanently sealing any unintended paths for air movement in and out of the house is a very effective moisture control strategy.

Figure 4. Air transport of moisture

The other two ways that moisture moves in and out of a home or building — diffusion through materials and heat transfer — are much slower processes. Most common building materials slow moisture diffusion to a large degree, although they never stop it completely.

CONTROLLING WATER VAPOR IN A CRAWL SPACE

The laws of physics govern how moist air reacts in various temperature conditions. The temperature and moisture concentration at which water vapor begins to condense is called the “dew point.” Relative humidity (RH) refers to the amount of moisture contained in a quantity of air compared to the maximum amount of moisture the air could hold at the same temperature. The ability of air to hold water vapor increases as it warms and decreases as it cools. Once air has reached its dew point, the moisture that the air can no longer hold condenses on the first cold surface it encounters. If this surface is within an exterior wall cavity, the result is wet insulation and framing.

FIgure 5. Condensation

In addition to air movement, you also can control temperature and moisture content. Insulation reduces heat transfer or flow, so it also moderates the effect of temperature across the building envelope. In our climate, properly installed vapor diffusion retarders can be used to reduce the amount of moisture transfer. In crawl spaces, insulation and vapor diffusion retarders work together to reduce the opportunity for condensation.

When looking for opportunities to improve the energy efficiency of homes and buildings, sealing and insulating of vented crawl spaces can improve the energy efficiency, comfort, and durability of the structure, particularly in climates with cold winters and/or hot humid summers. However, before any sealing and insulating of the crawlspace walls can take place, water drainage and moisture management issues in and around the crawl space must be dealt with to ensure that the crawlspace will be dry and remain dry once enclosed.

Controlling the intrusion of water and the movement of water vapor, air, and heat through the building envelope by proper design and construction of wall assemblies are major goals in the mixed-humid climate zone.

At DriTek Solutions, we are experts at foundation waterproofing, drainage solutions, foundation repair, and crawl space encapsulation. We can help you with all your foundation needs.


Q: What are the best practices for waterproofing crawl spaces?

A: You might be thinking: This is all new to me and I’m not expert – what are the best practices for waterproofing crawl spaces? You’ve come to the right place. At DriTek Solutions, we ARE the experts at waterproofing your foundation in the Atlanta, GA area. Following are the best practices for waterproofing crawl spaces and crawl space encapsulation.

HOW TO ADDRESS WATER INTRUSION ISSUES IN A CRAWLSPACE

Several steps can be taken to address moisture issues in the crawlspace, depending on the initial conditions at the site and the project budget:

  1. Reduce the chances of bulk intrusion of water into the crawlspace by re-grading the ground around the building to slope away from the structure, installing drainage pipes around exterior footings that drain to daylight or a dry well, and installing or modifying gutters and downspouts to ensure that they carry rainwater away from the foundation. Ensure that any existing concrete patios, sidewalks, or driveways slope away from the house. If they slope toward the house, consider replacing with pervious pavers or correctly sloped concrete, or install drains, for example at the base of a down-sloping driveway, to carry water away from the foundation.
  2. Block off and thoroughly seal crawl space windows and vents with durable, waterproof materials that will prevent air and water leakage. Completely fill crawl space window wells to above-grade levels.
  3. Install a dehumidifier suitable for the cubic footage of the crawlspace to condition the air inside the crawlspace for acceptable humidity levels.
  4. Install sump pumps in low-lying areas of the crawlspace floor that can be activated to carry away any water that accumulates at the crawl space floor from seepage under the foundation walls or rising water table from periodic storm events. The sump pump should have a plastic pit that is 2-ft to 3-ft deep and perforated with holes drilled in the bottom so that if the water table rises (for example due to storm events), the water will be removed before it reaches the floor of the crawlspace. Use sump pumps that are equipped with gasketed, tight-fitting lids. For more on sump pumps, see the guide Drain or Sump Pump Installed in Basements or Crawl spaces.
  5. Install a vapor barrier of 20-mil or thicker polyethylene sheeting that completely covers the crawlspace floor and extends up the walls or columns to within 4 inches of the floor joists above. The plastic should be secured with pressure-treated wood furring strips, mechanical fasteners, or fiberglass mesh tape and duct mastic. Seams in the vapor barrier sheeting should be overlapped 6 to 12 inches and taped. This vapor barrier can be covered with a concrete slab for additional durability.


EXTERIOR WATER INTRUSION INTO CRAWL SPACES

Figure 1. Bulk water intrusion in a crawl space

The presence of water in a basement or crawlspace or evidence of seasonal standing water (damp areas, mildew, discoloration of the foundation walls, etc.) must be investigated and treated before renovations such as air sealing and insulating are undertaken. If interior sources such as plumbing leaks have been ruled out, consider the following potential sources.

Roof Drainage: Inspect gutters and downspouts to ensure that water is draining and is not allowed to collect near the foundation but is discharging to a storm sewer system (if allowed), a well or basin, retention pond, ground that slopes away from structures, or yard bubblers that are a minimum of 10 feet away from the foundation.

Grading: Ideally, the ground should slope a minimum of 5% away from the foundation walls for at least the first 10 feet to direct groundwater away from the structure on all sides. Any patios, driveways, porch slabs, or sidewalks should slope away from the house at a grade of 2%. If proper slope away from the foundation cannot be established because of the home’s elevation and surrounding grade, a surface drainage system should be installed to collect water and divert it away from the foundation. Another option is to install below-grade drainage pipes at the foundation footing.

Sprinklers: Turn on all sprinklers installed near the foundation to observe their flow pattern. The sprinklers must be positioned so they do not subject the foundation to water.

Foundation Waterproofing and Drainage: Implementing foundation waterproofing and a perimeter drain strategy on the exterior walls will be required on problematic sites. Some sites have high groundwater or water flow against the foundation that cannot be remediated in any other way. If the bottom of the crawlspace is below grade, the exterior of the foundation wall should be waterproofed.

Crawl Space Vents: Crawl space vents can allow bulk entry of water if they are located at or below grade. If the dirt and ground cover cannot be removed to slope the ground away from the house, installation of French drains or another drainage system will help direct water away from the house.

Sump Pump: In areas with poor site drainage, group 2 soils (such as the clay we have here in Atlanta), or a high water table, a sump pump can be installed to pump water from the foundation drainage system into an approved sewer system or other appropriate location. If a sump pump needs to be installed, the contractor should grade the crawl space floor with at least a 3% slope toward a low-spot collector to direct water to the sump. A battery backup for the pump should be installed, especially in areas with a high water table. It’s also necessary to make sure the sump has a tight-fitting, gasketed lid. The drainage system should discharge into an approved sewer system or to daylight.

Figure 2. Bulk water in a crawl space

CONTROLLING BULK WATER IN CRAWL SPACES

Controlling bulk water on the exterior of the home or building is the first step when encapsulating a crawl space. It’s very important to ensure that all of the details to control bulk water that were identified during the evaluation process have been examined and corrected where necessary (such as those discussed above). For example, bulk water from the roof can be drained away from the foundation via downspouts that are connected to a storm sewer or collector drains, and bulk groundwater against the foundation can be drained away through a perimeter foundation drain solution. Here are some additional specifics:

  • The moisture content of the wood in the crawlspace must remain below 17%. Moisture content greater than 17% is of concern and should be investigated.
  • Ideally, grading around the perimeter of the building has a 5% slope away from the foundation (6 in. within 10 ft). If this is unachievable, then it’s necessary to evaluate the landscaping. Drainage swales or surface drainage systems might need to be implemented around the perimeter of the foundation.
  • All sprinkler flow must be directed away from the home.
  • All roof runoff must be directed away from the building a minimum of 10 ft or via an underground drain system.

Depending on site conditions, if there is high groundwater or recognizable bulk water flow against the foundation that cannot be remediated any other way, implementing a waterproofing solution might be necessary. Waterproofing of all below-grade portions of the foundation and continuous perimeter drains might be required to prevent subsurface groundwater from saturating the foundation system.

LEARN MORE ABOUT CRAWL SPACE ENCAPSULATION HERE.

These are the best practices for waterproofing crawl spaces for homes and buildings. If you are in need of waterproofing and encapsulating your crawl space, at DriTek Solutions, we can help. We are experts at finding solutions to your water intrusion problem. We are the best choice for foundation waterproofing, drainage solutions, foundation repair, and crawl space encapsulation.


Q: Atlanta is a mixed-humid client. What does that mean for me and my house?

A: At Dritek Solutions, we love our city – Atlanta, Georgia. Having lived here all our lives and having worked here with the homes and the land for 28 years, we have become experts about the climate and soils that impact houses and buildings in our beautiful home city.


In Atlanta, GA, and the surrounding areas, we live in what’s called a mixed-humid climate. Homes and buildings in the mixed-humid climate must be able to address solar gains in the summer, medium to high humidity, mild to cold temperatures in the winter, torrential downpours, high winds, and tornadoes, especially in the midwestern and southern states.

A few inches of rain falling on the roof of a house can produce several thousand gallons of water runoff. This runoff must be channeled away from the building foundation to keep the basement or crawlspace dry and to prevent water from seeping into the building interior where it may create moisture problems. If not drained away from the house, the immense volume of water coming off the roof can quickly saturate the soil surrounding the building and wick through the foundation to the interior. Once inside, this moisture can lead to a variety of problems, including mold and rot. Moisture in homes is both a cause of indoor air quality problems and an important factor affecting the durability of the structure.

As a whole-house best practice, it is important to design the house exterior with climate-appropriate flashing, overhangs, gutters, downspouts, and drainage planes to shed rainwater and conduct it away from the house. Gutters and downspouts, as well as foundation waterproofing and drainage solutions, are particularly important to keep water away from the building foundation in areas with expansive soils, such as here in Atlanta, GA and the surrounding areas.

Expansive soils swell when they get wet and can put extreme pressure on foundations, even to the point of causing cracking or uplift of foundation materials. At the very least, when these soils get wet around a building, they can create a trough that collects water, increasing the likelihood of that water seeping into the foundation.

The temperature variations, forces of driving wind and rain, and medium to high humidity levels can take their toll on houses and building. Homes must accommodate significant heating and cooling needs and combat the effects of heavy rain and condensation from humidity, which can degrade structural materials, contribute to mold growth, and cause premature aging.

Here are some recommendations from Building America for homes in the mixed-humid climate:

  • Build slab-on-grade foundations and grade lots to drain away from the structure.
  • Create a tight thermal envelope and install a positive pressure ventilation system.
  • Place the air handler and ducts in conditioned space or go ductless with mini-split heat pumps.
  • Plan for storm-water runoff with adequate gutters, flashing, and kick-out diverters. Use pervious paving, vegetation, grading, and swales to handle large storm events.
  • Install a dehumidifier to control shoulder-season humidity.
  • Install a thermostat with humidity controls.


Because we are experts on the climate and soils that impact houses and buildings in our beautiful city, Atlanta, GA, at Dritek Solutions we can help you with all your foundation waterproofing, repair, and drainage needs.


Q: What are the principles of a healthy house and how can Dritek Solutions help me?

A: In this article, we’ll talk about:

  • Principles of a healthy home
  • Recommendations for maintaining a healthy home
  • Common signs of a moisture problem

At the end of this article you can find:

  • QUESTIONS THAT DRITEK SOLUTIONS CAN ANSWER

At DriTek Solutions, we believe that our homes should be our havens. Everyone deserves a healthy home in which to live and love. There are 8 principles or essentials of a healthy home. Ideally, a healthy home is:

  • Dry
  • Pest-free
  • Clean
  • Contaminant free
  • Well-ventilated
  • Temperature-controlled
  • Safe
  • Maintained

FACTORS THAT MUST BE CONTROLLED FOR A HEALTHY HOME

To address the 8 principles for a healthy home, the design, construction, renovation and maintenance of a house must control the following factors:

  • WATER
    • Rainwater control
    • Groundwater control
    • Indoor humidity
    • Plumbing
  • AIR
    • Big holes and building boundaries
    • Cold surfaces
    • Indoor humidity
    • Airborne pollutants
    • Pressure changes
  • COMBUSTION
    • Combustion appliances
    • Garages
    • Smoke
  • DUST
    • Entry control
    • Lead dust control
    • Cleanable surfaces
    • Filtration
  • CREATURES
    • Keeping them out
    • Reducing food and water


RECOMMENDATIONS TO CONTROL SOME OF THE ABOVE FACTORS

At DriTek Solutions, we can help you control many of the principles for a healthy home. One of the main concerns for every house is water. Water is a precondition for mold, insects, rodents, and dust mites. And it is arguably the single most important factor in the design and construction of a healthy home. Water is the most important factor affecting the durability of a home and the most important factor affecting maintenance costs.

If you control water, you have fewer biological pollutants, increased building durability, and lower maintenance costs on your home. The most important exterior sources of water requiring control are:

  • Rainwater control
  • Groundwater control
  • Humidity
  • Plumbing

One of the key elements to controlling water is the concept of drying. It is common sense to accept that things will get wet. The problem is not that homes get wet; it’s how long they stay wet and how well they dry. Homes should be designed to dry.

RAINWATER CONTROL

The main principle of rainwater control is to shed water from the house by layering materials in such a way that water is directed downwards and outwards from or away from the building. This principle applies to walls, roofs and foundations.

FIGURE 1: Proper Drainage of Site

Layering materials to shed water applies to the building as a whole (see Figure 1). Overhangs can be used to keep water away from walls. Canopies can be used to keep water away from windows, and site grading can be used to keep water away from foundation perimeters. Drainage is the key to rainwater control. In order for drainage to work properly, it must drain the building site or land properly (Figure 1) and drain off and from the building properly (Figure 2).

FIGURE 2: Proper Drainage of Building

Successfully executing strategies to control bulk water and water vapor for foundations is critical for the durability of the house, increased indoor air quality, and creating acceptable conditions and/or living spaces within the foundation space.


IN SUMMARY:

  • Ground water must be managed: in order to prevent water entry into the foundation, it is necessary to prevent water accumulation against the foundation walls and/or under the slab (or ground cover). Water accumulation results in hydrostatic head pressure, which will push water through any available joints, imperfections, or cracks in the foundation. Accumulation is prevented by the use of drainage. Figure 1.
  • Surface water must be managed: the roof surfaces must be waterproof and concentrate rainfall at points around the perimeter of the building; this water must be shed off and away from the foundation. This is typically done with gutters and downspouts that are directed away from the foundation, correctly grading the site away from the foundation, and reducing the water permeability of the surface around the foundation. The goal is to saturate the soils around the foundation with as little additional water as possible. Figure 2.


COMMON SIGNS OF A MOISTURE PROBLEM

Most foundation and below-grade walls are constructed from poured concrete or concrete masonry block. Concrete products are porous and, unless treated, are not waterproof, allowing water to migrate into the building.

Common signs of moisture problems in existing foundations can be seen as visible water or puddles, visible staining of interior finishes, mold growth, and efflorescence (water-borne white mineral salt deposits). Interior finishes or insulation may conceal the presence of bulk water issues for extended periods of time, and problems may not be evident until damage is extensive.

At DriTek Solutions, we believe everyone deserves a healthy home. We can help you in your quest to provide a healthy house for yourself and your family. We are experts at foundation waterproofing, drainage solutions, foundation repair, and crawl space encapsulation.

Remember:
You have
options Atlanta!

Let us help you protect your
biggest investment by keeping the water out!

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You can click here or call us at:

770-963-9393

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and let us show you the DriTek Difference.