Drainage Hints Back to Drainage Plans

Drainage is a critical element in any project and one that is too often overlooked until there are problems. There is no drainage problem that can't be solved unless you live in a flood plain or on the banks of a natural waterway. Things to consider if you have a drainage problem: Are the downspouts from your gutters tied in to your drainage system? Is your drainage system trying to flow uphill? (Water doesn't go that way without a pump.) Did you just finish sodding your yard without grading it first? Are your gutters filled with debris? If you don't have gutters, is the water rushing off your house and blowing out your beds? Is there 6 inches of water on your floor after a rain? Is your ENTIRE drainage system based on either 4 inch pipe or that black bendy thin pipe (ADS)? Are your drains too high to collect water? Does water slope to your door and collect there? Do your drains clog with debris? Is there water in the pipe when you take the lid off the catch basin? If you have answered yes to any of these problems — there is a solution! Here they are: If you live in a FLOOD PLAIN - Move. If your house is still standing, then you haven't been there long enough to see a 50 year or 100 year flood. TO GIVE YOU AN IDEA ABOUT STORMS: Rainfall is calculated in intensity by inches per hour. Amount of water by "x year storm" is calculated by total rainfall in a 24 hour period. Two inches of water in one hour will most likely cause some flooding, but 13 inches in one 24 hour period is roughly a 10 year storm. Information about "x year storms" in the US will be posted here next month. Click the map below to see a larger version of the 100 year flood plain. Tie downspouts to drainage system. This will serve 2 functions. The pressure exerted by the force of the downward water will help clean out your drain lines and water won't run over the surface of your site and/or create puddles. Water and something else don't flow uphill without a sump pump. Grade turf areas at a 2% downhill minimum. Grade paved surfaces at 1% minimum downhill. Anything less will create "bird baths". Adding sand in those low spots will help reduce the ponding effect. Add ¼ inch to ½ inch at a time until you get the desired effect -- Wait until the majority of the grass grows through the sand before adding another layer. OR Pull Up and Regrade and then lay down new sod. I would suggest getting someone with a level to help assist you in staking the areas so you know what the proper minimum slope should be. REMEMBER 1% = 1 foot in 100 feet 2% = 2 feet in 100 feet or 1 foot in 50 feet 1 inch is NOT 1% OF A FOOT THERE ARE 12 inches IN A FOOT and 1 inch = 1/12 of a foot. 1 inch = 8.33% OF 1 FOOT Clean out your gutters -- they work better when they are empty and flow is not impeded. As far as I have found, gutter guards to not work -- but getting larger gutters (6 inch oversize/commercial grade) does work! How to Make a French Drain: If water is rushing off your roof -- draw a line with paint where the water hits the ground. This will be the center line for your French drain. See detail below. Dig a trench around your house, using the paint line as a guide. Make the trench about 8 inches wide and 10 inches deep Add 2x10 pressure treated lumbar to plant side of the trench. Put large rock in trench. Put a perforated pipe in the trench. Cover all sides of the pipe with 2 inch brown gravel. Do NOT use tiny little pea gravel or big huge rocks. when you order the gravel ask for 2 inch BROWN SPECIAL - the person at rock yard will know exactly what you are asking for. After the rock encased pipe is in the ground and next to the pressure treated lumber, finish off with additional rock. Make sure the top of all the rock is at least 2 inches below any weep hole or stucco. See detail. After you have finished making a ring around your house, tie the French drain to minimum 6 inch pipe (preferably 8 inch pipe) and slope at 1% for 6 inch pipe (0.75% for 8 inch pipe) to the street. When you are 3 feet away from the street, make a catch basin. This will let the water flow out even if the gutter is full. If you get into the french drain and have a problem, stop and ask for help! If you have a severe water problem that is causing you to pull up floors or roll up carpets - consult an engineer. You can ask a specific question on-line, but we don't diagnose problems we can't see. However, we see this problem on a regular basis. Four inch pipe is cheap - that is why most people like to use it. Also, one doesn't have to dig a big hole, when using 4 inch pipe - a sharp shooter will get the job done. All 4 inch pipe will rarely solve a drainage problem. The total runoff of a roof on a house can probably be channeled through 4 inch pipe initially, but if additional areas need to be drained, 4 inch pipe is often insufficient. Black pipe or ADS is ILLEGAL in every county, municipality, city, and/or in this country! It degrades and is useless in about 10 years! If your drains are too high, lower them or add soil/sand to the grade around them. Make the drain rim the lowest point. If water slopes to your door - check the other problems listed. If this does not solve your problem - consult a civil engineer. We can't diagnose a problem we can't see. If there is the potential to add a drain in an area (even paving) close to the door, do it! CLOGGED DRAINS NEED PERIODIC MAINTENANCE. Water standing in pipes is usually a sign that there is not enough downward slope to the pipe. REMEMBER: NEVER CONNECT TO A SANITARY SEWER LINE. SANITARY SEWER DOES NOT MEAN CLEAN, IT MEANS TOILET! If you have a connection to one cut the pipe and reroute it to a gutter or culvert - a sanitary connection can cause a smelly problem if it backs up. It is legal to tap into a storm sewer or storm drain. Storm means Rain! this is the preferred method. Portfolio for Drainage