How Do Engineers Handle Rainwater?

Engineers can help with proper fitting of gutters, or eaves troughs as they are called in some parts of the country. They are an important part of the drainage system around your house.  If yours are nonexistent, in poor condition, or improperly placed on your house, they could be causing problems and putting your home at risk of water damage.

Gutters need to be installed properly so that they catch the water coming off your roof and channel it away from your house and its foundation.  Your eaves troughs should have a downward slope of 1/2 inch for every 10 feet of run to ensure they drain completely.  If your house is more than 40 feet wide, the optimal installation would have the gutters sloping down from a high point in the middle to a downspout at each end of the house. (See Figure 1. Below)

All gutters need to be firmly attached with the center of the downspout aligned under the lip of the roof. Screws are the best option for connecting gutters because they won’t back out over time. Gutters can be made up of sections of trough (usually 10-12 feet long), or installed as a long continuous piece up to 37 feet long. If yours are in sections, make sure the seams are well sealed and water doesn’t leak through. Gutters that leak are a problem not just because they drip water on your head, but because the drips land close to the foundation. (Solutions)

(Roof Gutters – Figure 1. Below)


Downspouts are Need Too

Downspouts need to be large enough to handle the large amount of water that can come running off your roof in a heavy rainfall.  The minimum size for a downspout should be 2×3 inches, but a larger size (like 3×4 inches) is even better. The larger size makes it less likely that anything will be able to block the downspout–even a tennis ball will drop right through, and you know water won’t back up into your gutters during a heavy rain and possibly overflow.

At ground level, the water from your downspout should be directed at least 5 feet away from your house. It’s best to have the water flowing onto a hard surface (like a driveway) or to have a fiberglass or concrete splashguard designed to spread the water and stop it from puddling on the ground. Flexible plastic diverters or hinge attachments for your downspout allow you to swing it up out of the way when cutting your lawn, so you’re not constantly tripping over the downspout.

(French Drain – Figure 2)

Engineering Codes Determine Proper Grading and Slope

Once the water is on the ground, it’s important that it doesn’t just sit there. This is where the grading of your property plays a role. Most building codes require that the ground around a foundation slope away from the foundation at a minimum of 6 inches in the first 10 feet and with another foot of slope in the next 100 feet. (This is a minimum–more slope will obviously help get water away from the foundation faster). Don’t change the grading of your lot, and if you notice some low spots developing, be sure to fill them. 

If you have a problem with water constantly accumulating in a particular area, you might consider installing a “French drain.” A French Drain (See Figure 2. Above) is a small trench with a perforated pipe surrounded by sand or gravel that directs the water flow away from the foundation following the grade. Not only will it get the water away from the house, it will do it without any possibility of water runoff damage or erosion. (Home Maintenance)

Should a Mechanical Engineer Check Your Home’s Outdoor Piping? 

1. Check the Attachments 

Make sure the gutters are firmly attached. A loose or broken fastener can change the slope and prevent the water from draining out of the troughs, causing it to overflow and pool in undesirable places.

2. Seal the Joints

Sectional gutters need to have the seams resealed with caulk or a sealant specially designed for gutters in order to prevent leaking. This is especially important in winter months. Water that freezes and expands in the gutter will eventually have to melt; weakened seams will allow it to leak and flow in the wrong direction. You can also choose to get seamless gutters, but you should do your research before deciding if this is right for you.

3. Clean the Channel

Gutters can plug up with leaves, seeds, and needles from nearby evergreens, so it’s important that you keep them cleaned out. Most people stand on a ladder and remove debris by hand. However, you can also use a hose or a pressure washer to clear them out at least once a year—more if there are lots of trees. (See Figure 2)

4. Install a Guard

If you seem to be constantly cleaning your gutters, consider installing a gutter guard to keep the bigger leaves out. Just be aware that this is not a 100-percent preventative measure. Any gutter guard system has to have some openings in it to let water in, so seeds and other organic material will also get into the troughs and will need to be cleaned out periodically.

5. Maintain Your Yard

Over time, soil will compact or wash away with the seasons, it’s important to maintain the grade of your property. Adding some soil along your foundation and sloping it away will help keep water out of your basement.

6. Protect Your Windows

The rain coming down on your house doesn’t just hit the roof. Some runs down the sides and into your window wells. Covers will keep this water out of the wells, and stop it from soaking into the ground right beside your foundation walls. ( Thermal Energy)

Engaging an Engineer for Home Maintenance

Though it may seem excessive to have a mechanical engineer involved in the design and maintenance of your rain gutters and other protectors of water, there are extremely valid reasons for doing so.  The end result will be fewer and less costly home repairs and fewer inconveniences.