Drainage is one of the most poorly understood areas in construction. In our service area (Oakland, Berkeley, Piedmont, and Alameda, CA) there are substantial issues with underground water from creeks, springs and water channeled from adjacent properties, requiring French drains in addition to surface drains for the downspouts and flat surfaces.
Often relegated to gardeners and landscapers with limited knowledge of the principles of proper drainage, poorly designed systems often create more water problems than they solve.
When designing drainage to protect foundations, retaining walls, and basement spaces we will carefully examine how water enters these spaces, and then make sure our system is sufficiently deep and properly located to do the job correctly. We will install a membrane system which helps preserve the life of foundations and retaining walls, an important consideration in our older homes.
By installing your drainage right the first time it should last a lifetime and keep the water where it belongs–away from your house!
Here are some of the drainage services we offer in Oakland, Berkeley, Piedmont, and Alameda, CA:
- Drainage Repair
- Drainage Design
- Drainage Systems
- Drainage Replacement
- Reconstruction of Old or Improperly Designed Systems
- New Drainage Systems
- Foundation Waterproofing
- French Drains / Subdrains
- Downspout Drainage
The first step in any drainage repair is to diagnose why your existing drainage is not working properly. It’s generally a function of poor design and construction in newer systems or a lack of drainage, or outdated clay systems in older work. Occasionally we can repair a system that is more modern with specific problems, but most of the time we are replacing them or installing new drainage with modern materials, properly designed.
Proper drainage consists of discrete French drains and downspout drainage systems, area drains and channel drains where needed, and foundation waterproofing. The details are critical: the depth, the materials, and their locations all determine our recommendation. Not unlike the roof on your house, small voids or irregularities in the drainage system can lead to leaks and failures that can be difficult to diagnose. Often these systems can be complicated on California hillside homes with multiple levels and large elevation differences from front to back, requiring deeper drains, sometimes in crawlspaces as well as at the exterior.
We provide foundation drainage, downspout drainage, and area drains as part of an integrated system for handling all of the water that affects your home at the ground level and below. We tell our clients we are trying to create a “moat” around their home–so that water will never be able to get to it.
Most drainage systems that fail do so because they are improperly designed or installed. A lack of waterproofing or mistakes in installation, insufficient depth, or combining French Drains and downspout piping are common culprits.
Reconstruction of Old or Improperly Designed Drainage Systems
Older homes need drainage for multiple reasons–both to prevent leaks, but also to preserve the life span of their existing foundations. Since water is the primary culprit in the deterioration of concrete, it is often worth investing in the proper drainage to avoid a huge foundation replacement bill, particularly with taller more expensive foundation walls.
New Drainage Systems
We generally recommend dual exterior drainage along with a membrane system to protect older foundations. Our competitors often recommend interior drainage in the slab to help solve these problems. The issue with this is they don’t prevent water from continuing to damage foundations and leak through them, and can therefore undermine the foundation structure if not done correctly.
We install a dual membrane system attached to the outside of your foundation as a secondary drainage barrier. We use EPDM on the inside because it is a tough rubber barrier that is hard to damage, and can be bought in widths up to 15’ so it does not need to be seamed (a common leak point). On the outside we use Miradrain, a common drain mat with filter fabric covering a waffle-like plastic material that acts as a mini-drainage system on its own. We don’t rely on mastics or the cheap asphalt-based systems some of our competitors employ because they don’t adhere well to the types of dirty and irregular foundation surfaces we typically encounter. A metal termination bar and caulking seal these membranes near the ground level. We often see membranes (done by others) not sealed at the top, with water getting behind them, causing extensive problems.
French Drains (or Subdrains)
French drains, also known as subdrains, are designed to handle subterranean water. Unlike surface water, water also travels underground due to a variety of sources, including underground creeks and springs, rising water tables, and water following cracks in the soil and voids created by trees, vegetation, pipes, excavations, boulders, etc. When you are on a hill, water will get driven under your foundation and pop up at lower points in your crawlspace, basement, garage, etc. This water is handled by drains dug below the lowest point where water is getting into the affected spaces, with piping, and trenches sloped properly to remove the water. The trenches are backfilled with gravel and wrapped in fabric to keep dirt out of them.
Most residential home owners don’t realize the highest volume of water affecting your house comes through your downspouts from your roof. Often this water drains directly adjacent to your foundation causing drainage and foundation issues. We attach solid piping to all of these downspouts, with all of the water taken away from your building to the street, or in some cases to a dispersion pit or dry well in your yard.