What are the Proper Grading and Drainage Requirements for Multi-Family and Commercial Properties?

Street Drain

How important is this for multi-family and commercial properties? What should I be looking for when I evaluate a building I am purchasing? What are the solutions?

How Moisture Affects Your Property

As I have mentioned previously, 80% of all issues with property revolve around moisture. When we talk about moisture issues many people think of areas such as the integrity of the roof or leaking windows. The fact is that the overall site and how it handles water due to the grading and drainage is a key factor in moisture-related problems.

Over time, when water is not properly routed off the site, it can cause considerable damage. This is particularly true of older properties. Until the mid 50’s there were no strict codes regarding grading and drainage. These codes developed due to numerous problems that occurred during the explosive building after WWII.

I have seen the effects of moisture first hand and how it can push a basement wall inwards as much as 4 inches in less than 20 ft!

Draining Water to Prevent Damage

The more construction that occurs, the greater the need to control water properly. As more ground is covered and roads are built, the water that used to soak into the ground now needs to be routed properly. It all used to go into the storm drains. This lowered the groundwater which caused other issues. Now it is necessary to have more of the rainwater soak back into the earth properly. This is so important that there are soil engineers who deal with this exclusively.

Most commercial sites are on flatter ground due to the need for truck access as well as the lower cost of construction. Most buildings constructed after about 1980 rarely have major drainage issues due to stricter codes.

Drainage Codes

Currently, the codes require all areas immediately around a building to slope away. This is the simplest way to handle moisture – allow nature to let the water move away from the building. However, if the ground immediately around the building slopes toward it, that needs to be remedied.

Drainage System Options

Fortunately, there are solutions. Area drains around the building can be installed. Concrete waterways are another possibility to get the water away from the building. An underground drainage system, usually called a French Drain, can be installed if needed. There are numerous possible solutions depending on the site. Sometimes the cost to cure can be very little and simple to do, such as extending the downspouts that are dumping the water against the building.

Each site is unique which is why you need to have a qualified professional examine the property and let you know the true conditions and what the best possible solutions are.

If you haven’t already seen what our unique RISK Assessment® includes, you can click here to see some examples.