Are your exterior walls, windows, expansion joints, roofs, balconies, decks, or basement wall leaking? We’ll stop it. 

ACS has been doing this over 20 years. We’re your guys.

What you can expect from us: 

  • Professional service
  • Upfront, honest pricing without hidden fees
  • Respect and courtesy showed to you and your property
  • Uniformed technicians arriving on time
  • Quality workmanship you can rely on

Don’t Delay.  Call Us Today. (925) 548-9748

“My company has relied on ACS as a valued resource for roofing and waterproofing for some years now. […] Timely and comprehensive proposals. Competitive pricing. Workable scheduling. Efficient and courteous workforce. Knowledgeable and experienced sales, management and office staff. Work product of the highest quality. […] We look no further than ACS for our roofing and waterproofing needs. Highly recommend.”

Tom Hastings – Business Owner


Need a reliable contractor?  ACS services HOAs, apartment complexes, commercial and industrial buildings. We are the second-largest veteran-owned business in the Bay Area.

Contractors make you nervous? Our professionals will set your mind at ease.

What if something goes wrong? We’ll do our best to make sure it doesn’t. If it does, we’ll fix it.s

Below Grade


Above: ACS workers fix below grade leaks in basement wall in Oakland by drilling holes at tight intervals, and injecting urethane waterproofing through the wall. 

Basements have their own unique waterproofing challenges because of extremely limited access to exterior walls and slabs below ground. How commercial waterproofing contractors stop water from getting into a basement depends on whether the building consistently sits in the water table and how much access they have to exterior walls and building slabs.

Negative Side Waterproofing – All buildings can benefit from negative side waterproofing, which means treating from inside walls and floors. The advantages include lower cost and faster application due to accessibility. There are two types of negative-side waterproofing materials.

  1. Penetrating Liquid Acrylic waterproofing materials seal voids and capillary openings where water seeps through. These liquid acrylic waterproofing products have expanding polymer or crystalline additives as part of their chemistry and
    after application, the additives grow into gaps.
  2. Cementitious Surface Coatings add a secondary cement-based barrier to inside walls. Cementitious waterproof coatings typically combine cement and a polymer and can be used on any concrete surface, above or below ground. The coating adds a hard but flexible water barrier. We push the material into any cracks or other water pathways.


Positive Side and Blind Side Waterproofing – Waterproofing outside exterior walls (positive side) and under the slab (blind side) are more difficult because once the building is up, you can’t get to them.

ACS waterproofing specialists use chemical grout injections to get into these hard-to-reach places. Chemical grouting stabilizes soil around the building with polyurethane. We insert steel rods and inject high-density structural polyurethane into the ground around the basement to convert fine granular soil into solid waterproof barriers.


Above: ACS provides waterproofing and building maintenance for most Cogir Senior Living facilities. Their Rohnert Park location, near Santa Rosa, had leaking skylights.

Waterproofing Your Roof
ACS offers a variety of roof coatings, and our experts can tell you which will work best for your roof. Choosing the right material keeps your building cooler, reduces energy consumption, protects the building from leaks, and extends the life of the roof itself.

Our Favorite Roof Coating Options

Acrylic coatings can be used on various roof membrane surfaces, including single-ply membranes and metal systems. The flexibility of acrylic-based materials enabled them to withstand movement in roof membrane surfaces. Acrylic resists ultraviolet radiation and can reduce roof temperatures.

Silicone coatings are highly elastic products that adhere well to the existing surface. Silicones are very weather resistance and rarely become hard or brittle. The material can withstand long-term exposure to ponding water. Silicone coatings offer excellent ultraviolet protection and stand up well in extreme temperatures and harsh environments.

Polyurethane coatings were developed for application over foam roofs but can now be used over a variety of existing roof membranes. ACS waterproofing specialist may recommend a polyurethane roof coating if your roof gets lots of foot traffic because it stands up best to that kind of stress.

Exterior Walls and Expansion Joints

Stucco and concrete walls require coatings that are durable, flexible, tough, and breathable. Our professional staff will recommend the best waterproofing material for your building and help prevent bubbling paint, concrete cracks, and delamination in exterior walls. Cement or general exterior acrylic paint does not provide the envelope of waterproofing needed. The right waterproofing, professionally installed, will safeguard the outer envelope of your commercial property from humidity, precipitation, extreme temperatures, and sunlight.

Exterior waterproofing materials include the cementitious and acrylic surface coatings described above for interior use, but we might recommend several other materials.

Thermoplastic offers a wealth of benefits. While more expensive than other materials, it is one of the strongest waterproofing materials on the market. Thermoplastic waterproofing can provide 50 years of durability.  When heated, the material transforms from solid to semi-solid, sealing panels of thermoplastic together.

PVC membrane material is a common roofing product made from polyvinylchloride. While it is used most often in roofing, we may recommend it under certain other circumstances. You can choose from reinforced or unreinforced membranes. With the reinforced membranes, you’ll receive more durability.

Concrete expansion joints separate concrete slabs or sections in a building.  Without expansion joints, concrete would crack. To keep water from getting into the joints, builders caulk the joints. When it breaks down, leaks begin, and when water gets into concrete, whether it be the slab beneath the building or the decks or a parking garage, damage follows. Failed expansion joints allow water to reach the reinforcing steel and connector plates.

Our ACS professional waterproofing contractors will remove the old caulking, repair any damage water may have done to concrete and steel reinforcements, and replace the caulking.



Above: Window of Cedar Hills Offices in San Francisco shows corrosion that is beginning to cause streaking on exterior paint. Cracking in window is also visible.

Windows are sealed and caulked when contractors install them, but sealants and caulking break down over time. When windows are initially installed, neoprene window gaskets provide waterproofing where the glass meets the outside metal window frames. Over time these gaskets degrade, shrink and rot. Any caulking added inside or out of the building also degrades. Once that happens, leaks around windows damage walls and floors and cause mold, water stains, pooling water, peeling paint, and loss in energy efficiency.

ACS can diagnose the problem and recommend either new caulking and gaskets or new windows. Flashings may also be to blame for water leaks, and we may replace those, too.

Our team will:

  • Remove and replace expired window caulking,
  • Remove and replace failing window gaskets,
  • Or recommend window replacements.


Above: ACS worker waterproofs apartment balcony with CIM 1000 urethane coating at One Pearl Place in San Jose. 

There are two types of balconies: enclosed balconies and open balconies.

Waterproofing an enclosed balcony mainly involves caulking and sealing doors and windows. In addition, we will apply a waterproof coating on the balcony wall and floor.

For the open balcony, the doors and windows must be waterproofed. A poorly designed floor drain may need attention, too.  We will evaluate the state of the existing flooring for the balcony and check for flashing damage, concrete cracks, and joint damage. After replacing or repairing any damaged materials, we can recommend new waterproofing. We usually prep and prime the existing coating and apply a multi-layer waterproofing over the existing deck. We also may recommend a knockdown, non-slip textured finish coating for balconies.


Patio and Decks

Above: An ACS worker applies acrylic coating to the Top of the Mounds, a San Mateo apartment patio.

Concrete decks or patios have all the waterproofing challenges that balconies and parking decks do, including high foot traffic. We address concrete cracks, flashing, drain, and joint problems. While decks today are often made from treated or manmade materials, the joists and support posts maybe construction grade lumber and subject to rot. We have solutions for that.  

We can apply sealant to your deck or patio but we also offer a variety of other patio and deck waterproofing services customized to meet your needs.

  • Ceramic or stone on a waterproof base
  • Heat-welded PVC or Hypalon works well for floating wood decking.
  • Acrylic coating with your choice of cosmetic finishes
  • Polyurethane coating over a concrete patio


Parking Structures

glossy concrete deck of parking structure

Above: ACS waterproofed this parking structure with a concrete deck coating in Oakland.

Parking decks consist of concrete over a metal support system. Between sections of concrete, expansion joints or spacers permit the concrete to move with the temperature changes. Even with regular maintenance, temperature changes, traffic, and corrosives like oil, salt, and deicers erode waterproofing and damage the structure.

Our experts can remove and replace spacers, replace any damaged or missing concrete, and apply a waterproof sealant to prevent future water damage. Coatings on parking structures need to be extra tough to withstand rigorous wear and tear.

We will lay down an attractive, high-performance waterproof system tailored to meet your needs for high traffic pedestrian and vehicle surfaces.

Call us for any of your waterproofing needs at (925) 548-9748.

Why Choose ACS?

We are one of the best professional commercial waterproofing contractors in the Bay Area.

ACS provides waterproofing solutions for every part of your building, from the roof to the basement.

Let us protect your valuable property from expensive damage. Call us at (925) 548-9748.