Category Archives: Uncategorized

Case Study
San Francisco Home Foundation

The Challenge
The Client had pur­chased a lot in San Francisco for a new home. As is typical of many City lots, there was a zero lot line condition: on one side there was an exist­ing home right at the property line and at 2 others, the edge of the foundation was right at the sidewalk. The plans called for excavating below both the founda­tion of the neighboring house and the City sidewalks.

Action:
The adjacent foundation was sta­bilized by hand-digging alongside and under the adjacent foundation and installing underpinning pits, before the mass excavation phase. Because the soils were type 1 it was not necessary to place shoring in between the shoring pits and it was also possible to make unshored vertical cuts at the sidewalk sides.
The foundation was then installed by placing drainage and water­proofing membranes directly against the cuts and shoring, and shotcreting the foundation walls.

Results:
Because of the techniques used, it was not necessary to over-excavate for double-sided forms and the excava­tion and foundation work were completed without any distress to the surrounding properties.

RWR Construction Inc. 200 Gary Place, San Rafael, CA 94901 (415) 457-5658 www.RWR-inc.com

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Case Study San Francisco General Hospital

The Challenge
A structural analysis of one of the hospital’s buildings indicated that it was vulnerable to severe damage during a significant seismic event.
The retrofit design called for installation of new footings and large diameter piers around the pe­rimeter of the foundation. The new footings as well as the existing interior footings required a series of tiedowns locking them down against uplift.

Action:
In order to install the exterior footings and tie­downs, first it was necessary to construct soldier beam and wood lagging shoring to a depth to 30 ft.
An opening was cut into the basement area from the shoring pit. Finally a small track rig was lowered into the pit to perform the exterior and interior tiedown drilling.
The 36” diameter piers needed to be installed 40 ft. deep directly against the existing foundation, while avoiding damaging the building.

Results:
The work was completed successfully. This San Francisco General Hospital building now stands reinforced against the possibility of a devastating earthquake.

San Francisco General Hospital
Earthquake Retrofit Strengthens Hospital Against Seismic Peril

Captions:
Craning drill rig into shored pit for tiedown drilling
A San Francisco General Hospital building required seismic retrofit
Drilling tiedowns through interior foundation footings
Shored pit with tops of tiedowns showing
Bringing 35 ft. long pier cage to site
Continuous flight augers used in tiedown drilling
Setting cage for 36” diameter x 40 ft. deep pier
Craning in double hopper grout pump for tiedown grouting
Placement of reinforcing cage in cased 36” pier hole

RWR Construction Inc. 200 Gary Place, San Rafael, CA 94901 (415) 457-5658 www.RWR-inc.com

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Our estimator, Trevor, got a call to inspect a foundation problem, and came back with these images, as well as measurements and assessment of the entire situation of the home.  Moisture has been getting under this house, and has done a lot of damage.   The recommended repair will include diverting water away from the home, removing and replacing damaged foundation and mud sill, and of course, making sure the home is level.

IMG_20140509_102057415

Failing Foundation and Rotting Mud Sill and Rim Joist.

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Cleaning, repairing or maintaining property drainage pipes can be a bothersome task, especially for busy homeowners in the San Francisco Bay Area, CA. However, preventive measures are strongly recommended to avoid problems down the road. Check out the helpful guide below for a cost-effective and worry-free drainage system.

Knowing the basics

Drainage6The system that collects and drains rainwater and subsurface water from a property is called a drainage system, while sewers collect waste from toilets, sinks and showers.
Drainage system pipes, trenches and catch basins should be kept clean as they are integral parts of property maintenance. Proper and timely maintenance of drainage systems in the San Francisco Bay Area is necessary to protect your home and land against flooding, water infiltration into living areas and under the house, and settlement of foundations. If your home is located at the base of a hill, water can come rushing down the slope in a storm and threaten your property.

In the suburbs, drainage systems outlet to a designated spot on the property or to the street, while in San Francisco, drainage systems are hooked up to the same sewer system that takes away household waste.

During the past decade, the prevailing thinking of how and where to collect rainwater and where to outlet it have changed. Now, the practice of collecting as much rainwater as possible from everywhere and then outleting it in a concentrated flow to the street or a stream is discouraged.
Instead, water should be collected only where it threatens to infiltrate the living areas or crawl space of the house or to cause softening of the ground under the house foundation and subsequent settlement.

The downspouts from the roof should be hooked into a drainage system and the areas around the perimeter of the foundation should either be sloped away from the house or have catch basins connected to a drainage system that collects the water. If the lawn and other areas get soggy, that’s ok, because the water will eventually seep down into the ground.

The drainage system should outlet into a “rain garden”. A rain garden can be an area anywhere on the property where seasonal ponding of water is ok. The water will, over time, seep into the ground, recharging the ground water.
This is now the preferred method for several reasons: it prevents the scouring of creek and streambeds that happens from concentrated loads of rainwater; the street drains are not overloaded; any contaminates that get into the water will seep into and be filtered out by the ground instead of ending up in waterways.

Identifying drainage problems

If you notice water is ponding at catch basins when it rains or downspouts appear to be clogged up or water is building up next to the foundation or in places that that used to drain, you have a problem. If it’s a catch basin, take off the grate and remove any debris and soil from the box. If it’s still not draining, stick a hose down the pipe connected to the box and try to wash the clog out. A downspout may be clogged up at the gutter: get a ladder and check your gutters, particularly where the downspout connects. Track down the reason why water is ponding in new areas near the foundation and try to figure out what has changed. If you have a concrete V-ditch on you property, make sure to keep it cleared of debris and free-flowing. Sometimes it may be necessary to use a plumber’s snake to clear clogged lines.

Leaving it to the experts

Property owners are responsible for keeping their drainage lines and systems cleared and well maintained. But sometimes, drainage issues are beyond the ability of homeowners to take care of themselves. That’s when it’s time to call in an expert. Get a contractor that specializes in drainage systems to come over and evaluate your property. He or she usually has years of experience in identifying drainage problems and installing the proper fixes.

When in need of proper repair or installation of drainage pipes and systems in the San Francisco Bay Area, it’s always a practical approach to employ professionals. Companies like RWR Construction Inc. can help you tackle your drainage problems. RWR can also take on your drilling and other engineering construction needs.

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Driveways have issues: cracks and settlement from ground movement, surface wear, drainage- it will and can happen. Murphy’s Law right? Driveways wind and slant this way and that, but sometimes they don’t drain well, especially if they were created on hillsides. Cars, weather, people, nature-you name it and it will decay it. right Either way, we need driveways. We need places to park our cars, and still want to make sure that the end of the driveway is not pooled with water, or starts cracking and dropping from what nature’s wear and tear hits it with.

Driveways in San Rafael and the Bay Area on hilly slopes need to be constructed and drained properly or they can result in slides or settlement and those are expensive problems. Construction is a big job, but if a contractor that specializes in structural work and knows how to build on hillsides is put on the job then San Rafael driveway repair will be done accurately. Besides new driveways, construction in San Rafael driveway repair can also involve using piers, tiebacks, retaining walls earth retention and drainage techniques. Walls provide lateral support to not only houses, but to driveways located on hillsides. In the Bay Area, retaining walls are made first by drilling or excavating, setting steel posts or rebar, pouring concrete, casting concrete walls or installing lagging pressure treated timber and more. These walls are for one thing, to create a border and strength to help structurally support driveways and maintain their location and height without further movement.

It’s Not Just Concrete That Makes A Road or a Driveway-It’s Also A Retaining Wall

These walls are critical, and their use and the construction of them go back millennia -archeologists find them scattered across ancient cultures. Why do driveways need properly designed and engineered retaining walls and drainage? For one, building a driveway with correct drainage means calculating slopes and sizing drainage systems properly to handle the amount of water that will be collected. Get it wrong and you will have flooding, pooling and ponding problems and can even have the water undermine your driveway. Improperly install a retaining wall and it can deflect or even fail, ruining your driveway and costing even more to fix. Hilly challenges persist across San Rafael and Marin County, and locating a contractor who can properly construct or repair a concrete driveway or retaining wall can be difficult. Look for experience and expertise and ask to see what they have already built. If you are in the suburbs or a city, with a modest house or a larger estate, you may need these types of services.

Of course there are other considerations, or rather other types of materials that are used to build driveways. For instance, many use asphalt because it’s a lower-priced option then concrete and can be used on flat ground, or on hillsides where the ground has already been properly supported. Driveways in the local San Rafael area and the Bay Area are always in need of repair because they have wear and settlement.

How To Stop A Driveway From Collapsing

The support system for a San Rafael or Marin County driveway on a hillside needs to be heavily structured and set in place to prevent a driveway from collapsing in the first place.  Asphalt driveways should always be laid over a base of crushed rock on solid ground that will not settle later. If the ground isn’t firm enough, it may need to be excavated and re-compacted first before the base rock and asphalt are put down.

Erosion, undermining, cracking and settlement usually happen because whoever constructed the driveway in the first place did so inadequately. Improper or inadequate drainage can cause a collapse, as can a broken buried pipe. In some cases it may even be due to a sinkhole, unstable marshland, seismic activity or simply hillside erosion. Contact your local San Rafael  driveway experts to help you today.

For more information, log on to acreagelife.com.

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