The protection of your home from flood waters, is in many instances the difference between salvaging your home after a devastating flood, or simply loosing it. There are several commercially available methods for reducing the flooding potential of your home. In addition, there are several clever methods of basically trying to keep the majority of the water from entering your home during a flood stage. The commercial methods are quite expensive and may not be within reach of the average homeowner, the other methods are somewhat less expensive, and obviously not quite as full proof.
This chapter is designated to methods of flood protection, aside from the raising of the entire structure. The raising of the entire structure above the flood waters will be explained and detailed in another chapter within this website.
Commercially available methods of flood protection
Flood Panels / The installation of flood panels is a commonly used method of reducing the flooding potential of your home. Flood panels are available through a limited number of contractors and suppliers. Researching the internet will identify the local suppliers of flood control panels as well as their installers.
Flood panels are installed in the lower openings of the home. These opening consist of doors, windows, or other areas of concern, such as vents, bilco doors, garage doors, etc. Most installations involve a temporary installation of flood control panels, that are installed upon weather alerts for flooding, and removed after the threat is gone. The panels can be constructed of aluminum, wood, fiberglass or other synthetic materials, and should be capable of withstanding considerable lateral water pressure. In most applications, a mounting bracket or channel is installed on either side of the openings to be protected. These receptors for the flood control panels are designed to hold the panels in place, as well as provide a watertight gasket between the panels and the receptor. The panels can either be assembled as one panel, or can be installed as separate panels to make the installation lighter and easier to manage. The storage of these panels, as well as the ability to secure manpower to install these panels at a moment’s notice, are coordination issues that must be resolved if commercial flood control panels are to be utilized.
In many instances, the use of commercially available flood control panels is focused on the commercial and institutional markets. Maintenance crews that are, in many cases, full time at commercial and institutional markets, will be available to install as well as store these panels.
The normal homeowner, unless willing to install the panels themselves, will need to verify that they can assemble a crew to install these panels as needed. Of course, like everything concerning the weather, you will not be alone when the time comes, and there will be competition for any installers of the panels. The ability to mount a work crew to install the panels is critical to the proper use of these removable temporary panels. In addition, after the flooding, the removal and re-storage of these panels will be another manpower task that will need to be fulfilled along with the other cleanup tasks that any major flooding will require.
Flood control gates, doors, louvers
The installation of flood control gates, doors, louvers or other assemblies that are permanently attached to the openings in the structure, is another method of permanent flood control. Again, research and internet searching, will identify those suppliers and contractors that are available to provide the installation of these types of flood control measures.
This type of flood control is in most instances, more expensive and definitely more permanent than the flood panel application. However, the installation of permanent doors, gates or louvers is less difficult to activate upon flood warnings, and does not require, in most cases the hiring of additional manpower to apply the system. Two other positive aspects of this type of permanent system is that there is no dismantling of the system nor storing of the panels once the flood threat has passed.
If a permanent door, sliding gate or other permanent system is installed, a professional installation company should be hired to install the flood control applications. There is coordination as well as space specifications that need to be considered and analyzed prior to the installation of such systems. Unfortunately the visual effects of sliding flood panels or swing gates must be addressed and in many instances do not blend into the general aesthetics of the facade of a structure. Permanent flood control has a tendency to appear institutional and overpowering, however, their ability to prevent flooding and damage is extremely successful.
Permanent flood control systems may not be the most aesthetic but there are the most functional.
Commercial structures that are subjected to serious flood conditions, in many cases are constructed to manage these flood waters. The same procedures can be constructed within a residential home with the same positive results. If a residential home is constructed in an area that is prone to flooding and water issues, the initial design of the home and the resultant construction should be guided accordingly. Proper elevation and flood control is essential to the code compliance of any structure within a flood prone area.
Waterproof slabs and foundation walls are in many cases installed to provide a ” bathtub ” effect. This effect, basically ensures that the water remain outside the basement elevation and is stopped by an impenetrable perimeter and basement slab. This is accomplished with the use of waterproof material such as exterior drainage board and membrane as well as special mastic coatings of waterproofing material. The bathtub effect of waterproofing a structure will also affect the structural design of this structure. To limit water on one side of the structure will exert a tremendous amount of lateral pressure on the foundation walls, especially as the elevation of the withheld water increases. Water exerts a force of over 64 pounds per square foot of water retained and can cause tremendous structural loading. All of this loading must be considered when designing a foundation that is intended to hold back the water.
In many commercial projects the use of an interior below grade drainage system, leading to sump pumps to pump the water out of the structure is used. This drainage system is constructed below the slab on grade prior to its placement and is designed to drain all under slab water to the sumps. Installed pumps are designed to pump the water from the sumps to the exterior storm drainage systems serving the building. This type of active pumping system along with the bathtub effect of waterproofing the foundation walls is the most effective means of flood protection. It is also the most costly and technically advanced. The construction of an active system, under the slab of a bathtub type foundation, is the ” belts and suspenders” of the waterproofing concept. If both of these concepts are employed on a project, this is the ultimate in flood protection. Aside from actually filling the basement up with water due to pump failure, the overall effect of an active pumping system as well as the waterproof bathtub effect should provide assurance that the flooding of the structure will be controlled.
Creative flood control systems and improvised methods of reducing the effects of flooding within your home.
If the more permanent flood control systems are not possible due to expense or convenience, then there are several methods, and procedures that can be implemented to reduce flood water damage.
The ability of sand bags to stop the water from entering the home is an old fashion, well proven system of flood control. The obvious negatives of a sand bag system is that there is a need to fill the sand bags at the time of need. This filling requires substantial manpower and if enough labor is not available there is not time to fill the number of bags necessary for proper flood control. In addition, the size of the bags will be limited, depending upon the strength, youth and physical ability of the installers of the system.
If there is any possibility of sand bag storage prior to their need, then this is obviously an answer to the timing, and work factor required, if there is a flood warning. Creative thinking, relative to sand bag storage, may allow you to prepare the bags and store them, prior to the need for the bags. Some creative areas.
a.) Create a raised area in the basement that has all the sand bags neatly stacked in one location. Place plywood or other rigid surface material over the stacked sand bags and create a stage effect for your children to play, on or simply an area to store household items.
b.) Neatly stack your sand bags along the perimeter of the basement foundation wall to create a neat seating effect along the perimeter. The stacking of the sand bags neatly will reduce any negative visual impact to anyone using the basement elevation. Or if the individual circumstance makes more sense, pick one wall elevation to stack the sand bags against to limit the effect of stacked sandbags throughout the basement area.
c.) Create areas for sandbag storage within the basement in places such as the underside of the your workbench, around the mechanical systems in the basement, in any crawl spaces within the basement areas, or under the stairwell leading down into the basement area. If there are areas that can use the neat stacking of sandbags as a functional element, such as the base of a ping pong table, train table or workbench, then the storage of the filled sand bags can be put to positive use.
d.) Neatly stack the sand bags in the garage spaces in a similar fashion as you did in the basement. Alongside the perimeter walls or even down the center of the garage, between the areas used for parking the cars. Again, as in the basement, the base of a workbench or other base for any other usable table surface can be used to store sandbags.
e.) Create landscape beds on the exterior of the structure. These beds can be covered with mulch to blend the sand bag landscape beds with the other landscaping around the home. Flower pots and shrubbery can be installed within the sand bags to further the effect of a normal landscaping bed around the home. To bury the already filled sand bags is a perfect method of storing the bags for future immediate and emergency use.
f.) Create composting areas, by using the stacked sand bags for the perimeter of the composting areas or even use piles of the neatly stacked sand bags as exterior seating around the home. The entire idea of this type of creative use for already made sandbags, is to have them available for immediate use when the time comes for the bags to retain the flood waters.
The point of finding areas to actually store the sand bags, is many fold. The bags can be filled in a leisurely manner throughout the year and stacked as fill for areas you have found. The bags should be a non-degradable material or even the common burlap bag. As long as the burlap bag is encased with a plastic bag of some sort of non permeable membrane, to keep the majority of the moisture out of the bag itself. The immediate need for several sand bags at a moment’s notice is solved by finding areas of storage for pre-made sand bags. This is an important aspect of using sandbags for flood control.
Careful observance of the building code is a must, when attempting to create raised thresholds for the openings in the home that have flooding potential. What is meant by raised thresholds, is the creation of a solid masonry deck, patio, or higher elevation, than the floor elevation of this opening. This creation of a raised elevation on the exterior of the structure will prevent any approaching water from accessing the homes doors, windows, louvers, etc. However, this approach must be creatively designed and constructed.
The design of the patios or raised elevations, as well as the drainage of these various elevations required to access the home must be carefully designed and considered. If the elevations of the home are raised one foot, then the actual elevation drop that must be accomplished, is this one foot elevation. This can be accomplished by a step down onto a platform that enters the home, or even a ramp effect that will allow the proper entry into the home. In either case, the use of drains must be located at the elevation of the lowest point in the entry and is a necessity that cannot be overlooked.
This is a static system of flood control. By static, what is meant, is that once the raised elevations are created, and the proper drainage installed, there is no need to implement any other system or activity upon issuance of a flood warning. This is a static system, and will function similar to a higher floor elevation within the home. This patio effect will provide a permanent barrier to the approaching flood waters, however, as noted previously the design as well as construction of these permanent structures must be carefully created to ensure proper drainage of the water.
Filled water bags
A creative method of flood control within a door opening is the use of two planks separated by threaded rods at the four corners. Dimension this box to fit into the door opening, and set the treaded rod, with washers and nuts to spread open to the width of the actual door jamb or frame. Place a heavy duty contractors bag in the middle of this constructed box and fill the contractor bag with water. The pressure of the water will push the bag against the door opening jambs and will fill the entire interior of the two planks with water. Fill this trash bag to the top of the plank system. This system will allow the full space between the two planks to be filled with water that presses on all surfaces of the system. If the planks are extended higher up, the entire interior of the system can be filled to provide pressure along the entire boxed opening.
What is extremely sensible about this type of flood protection, is that any size opening can be filled with contractor bags. Several bags can be lined up to allow the entire opening to be filled with water within the bags. The water pressure itself will allow the adjusted spacing of the two plank to spread apart according to the positioning of the nuts on the exterior of the planks. This system requires almost no storage space, is easily and efficiently installed and can be dismantled by either slicing the contractor bags or simply loosening and removing the nuts from one side of the form. The real creative individual can actually set up a fill system off of the gutter system around the perimeter of the home. This system can be used to fill the garbage bags with rain water as the water washes down the roof slope into the perimeter gutters. Granted, this system will take some ingenuity, but could be quite fun to construct for the creatively ingenious engineer amongst us.
Obviously this system will not keep all the water from entering the structure, however it will stop the majority of the damaging water from directly entering the structure. The system will stop the water enough to allow individuals to control the entry of the water by mopping and bailing from the interior of the structure.
The explanation of this type of system is intended to identify the creativity that can be used to try and stop the majority of the flood waters from entering the structure. Not meant as a 100% system that is capable of stopping all of the water, but hopefully, enough of the flood waters to minimize the amount of damage that flood waters can cause.
The use of wood planks to span the opening where water will enter the structure and the covering of these planks with plastic contractor bags, will reduce the input and the flow of the flood waters. Again, like the filled water bags between the two planks the system, this is not 100% full proof regarding water integrity. However the system will stop the majority of the flood waters and may allow ample time to keep up with the entering flow of water with mopping and bailing. Any obstacle to the onslaught of the flood waters is better than no obstacle. Even the use of plastic closed into the exterior doors in an effort to wedge a plastic barricade to slow down the water is better than nothing. Creativity and ingenuity can be used to hopefully reduce the damage of flood waters into the home.
A creative layout of exterior landscaping can also be designed to minimize the entry of water into the home. The use of proper grades and elevations will stop the water, or direct the water away from the entrances to the home. However, the creation of a perimeter waterproof barrier of masonry can eliminate the majority of the flood waters from entering the home. The use of a pump system to remove the water that is accumulated within the low areas of this retainage system would eliminate the need for other flood protection measures. If the landscaping can be accommodated to properly keep the water away from the home, this is the best of the alternate solutions.
The creation of lower swales to guide the water away from the home is another landscaping design possibility to prevent the entry of water into the home. The proper positioning of these swales by an experienced site contractor can make the potential for flooding much lower by simply directing water away and not toward the home. It is essential that when designing your home, the site contractor be cognizant of any flooding possibilities and thoughtfully grades the exterior around the home to allow the water to move away and not collect around the perimeter foundation.
Another important aspect of proper draining around the home is the proper placement of the foundation of the home. I have witnessed incorrect elevations of foundations that have resulted in water accumulating around the home and eventually causing issues. Make sure that the home is designed high enough to allow positive water flow away from the home and not towards the perimeter foundation. Setting the house high enough on the site is extremely important to position the home at an elevation that will direct water away and not towards the foundation.
Perimeter gutters and leaders
The proper placement of gutters and leaders around the perimeter of the home will reduce the amount of water deposited around the perimeter of the home. If there are no gutters and leaders, the water will simply wash down off the roof and enter the soil directly around the foundation. This will cause water to accumulate around the foundation walls and seep down into the earth accumulating around the foundation. Once the accumulated water starts to develop a head of water, meaning it is building up and not draining away, the water will force itself into cracks and crevices within the foundation walls and enter the basement of the home. Keeping the water away from the foundation is essential to the proper management of water into the basement of the home.
The direct piping of the leader system of the home is also an important aspect of moving the water away from the foundation. If the leader system is directly piped to the daylight, which means the pipe simply exists out of the ground, or there is some type of pond or accumulating structure for the water away from the foundation, this will reduce the amount of water entering the basement elevations.
In some cases, large dry wells created to allow the water from the leaders to enter the drywells and slowly dissipate out into the earth surrounding the drywell. A drywell is basically an excavation that is filled with a permeable material such as gravel to allow the water to enter and slowly percolate out of. This type of construction should be designed and engineered by an experienced site engineer to properly size and design this retainage system.
Curtain drains / Trench drains
A curtain drain, is a drain that is constructed at the bottom of a hillside, the bottom of a sloped area of drainage, or at the perimeter of a foundation wall. This drain is designed to allow the water to enter a piping system and drain out to either daylight or another type of retainage system. A curtain drain is intended to curtain the area that is being protected from the flood waters. The positioning of the drains is important to allow the majority of the draining water to enter the curtain drain and drain away from the structure. The piping must be pitched in the proper manner to properly discharge this water away from the areas being protected from flooding.
A trench drain is similar but is similar to a trench drain, but is normally located so that the surface water will enter the top of the drain, through an open grate in the drain. The drain is normally a linear assembly of plastic, metal or concrete and has a grate set in the top of the assembly to allow the water to enter this assembly. The trench drain bottom is pitched to allow the water to flow away from the area being protected from the flood water. Trench drains are very common at the bottom of sloped driveways or at loading docks to prevent water from entering the garage space or accumulating at the bottom of the loading dock.
In new construction, the location and construction of the curtain drain must be designed and located according to the site layout of the perimeter open surfaces of the site. If the site is pitched towards the structure, the curtain drainage system is normally installed at the bottom of the sloped hillsides to catch the water prior to it getting to the foundation of the structure. In some instances, if space is limited or the site layout requires it, the actual curtain drain is positioned against the foundation wall to catch all water that is flowing toward the foundation wall.
In many instances when water is infiltrating the foundation wall of an existing structure, the best way to correct this water infiltration is the installation of a curtain drain. This drain must be positioned alongside the foundation wall to intercept the water draining towards the structure. Once the water is intercepted, the curtain drain acts as a conduit for the water and drains the water away from the foundation wall. Unfortunately the installation of a curtain drain in most cases is a very labor intensive activity and requires excavation equipment and an experienced work crew. However, once the proper curtain drain is installed the infiltration of water through the foundation walls is eliminated.
Proper flood protection of any structure is much easier and efficient if performed during the construction period of the structure. Proper design and engineering is necessary to interpret the flow of water around the structure and design the site drainage systems to move the water away from the structures. This webpage only identifies possible solutions to water issues without raising the structures above the mean flood plain. This procedure and concept is discussed and identified in the page
” Raising your home to prevent flooding “
Water is a beautiful commodity if controlled around the structure. However, it can cause severe damage and destroy property. The controlling of the water around the structure is necessary for comfortable living, and is a necessity for residential, commercial and institutional structures.