After doing over 30 to 35 foundation repairs a year in San Diego, California, we can tell you exactly why these foundation failures, cracks, and issues occurred. It usually comes down to improper roof and surface drainage on expansive soils and poor surface grade around the home.
Most homes in San Diego county are built on expansive soil. The worst thing you can do if your home is on this type of soil is to let water stand or pond next to the house without proper drainage away from the home or an area drain system. All homes should have an eave gutter downspout system connected to a below grade SDR35, non-perforated pipe system discharging to the street or other legal water coarse.
Expansive soils are a recipe for foundation failure, cracks and other damage when you have poor surface drainage. When water does not drain away from a home on a slab foundation or a raised foundation with 18 inch crawl space the home is subject to soils movements resulting in foundation settlement or heaving.
Additionally, trees should not be any closer to a house than 20 feet. Homes with trees within 20 feet are subject to foundation heaving due to root intrusion under the foundation.
San Diego gets enough rain (especially in the flash flood prone years – once every 8 to 13 years) to put your home foundation in jeopardy if you don’t have proper drainage in place. By the way 2015 is a heavy rain fall prone year.
Take a look at the perimeter of your home. Notice if the surrounding land slopes toward your home or away from your house. Then notice for what distance it does slope before it changes direction. If you don’t see a clear slope down and away from the home, check out the following tips to learn more about proper drainage for the prevention of foundation subsidence and cracking.
Save your foundation by following these drainage tips:
1. Check Your Property Grading
All surface grading at the house should be 6 inches or lower than the top of the interior concrete slab or wood framing and should drain away from the house at 1/4 inch per foot fall for a minimum of 5 feet.
At this point the grade should drain to the street or other legal water course. If this is not possible due to existing grades and improvements, then install 6″ diameter or square area drains connected to a 4″ diameter, SDR35, non-perforated pipe system discharging at the street or other legal water course. In addition, connect all your eave gutter downspouts to this system.
2. Install Gutter System Properly
Install roof gutters that are hung level, tight to the roofing material with one downspout for every 20 linear feet of gutter. Each downspout should have an attached tight line pipe discharging all roof waters at a minimum of 10 feet from the house or onto a hardscape or other proper drainage channel.
3. Install Irrigation System Properly
All irrigation valves should be a minimum distance of 10 feet from the house plumbed from house to irrigation valves with 3/4 inch, “L” grade copper pipe.
Foundation Repairs Can Be Avoided
As licensed Engineering Building Contractors in the state of California we get many clients coming to us who need a complete redo of other general building contractors’ work. Why? We understand engineering and most general contractors do not. Engineering Building Contractors are licensed to do structural repairs on residential, commercial and industrial buildings. We are also licensed to work in city streets.
Most general building contractors use outside engineers and have no way to know if their engineering designs are usable or feasible. Often times the drawings we see from these outside engineers are not buildable. These designs often over engineered, and are more about getting around legal issues instead of doing a good job that will meet the needs of the client. In other words, they are too costly to build. Additionally, if a general building contractor (who knows little if anything about engineering) brings in an engineer, there is no way for the general building contractor to evaluate the quality of the engineering and/or challenge any part of the design. Thus, there is no oversight of the engineers on your project.
Engineering Building Contractors Offer Higher Quality, Value & Will Save You Money
At Dakini Engineering General Contracting we vet and hire the best engineers and provide in-house engineering services (including civil, structural, soil and geo-technical) in San Diego county. Even if you don’t need extensive work done in these areas, having this background allows for a big picture when designing and building your project. We understand engineering and work collaboratively with engineers to build your the most efficient and cost-effective design.
Because of our experience and expertise in foundation, landslide, drainage and hillside repair, we take on and successfully design and build projects that most other contractors won’t. We welcome your call today.