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Best basement waterproofing pros near Diamond Bar, CA

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Top-Rated Basement waterproofing pros in Diamond Bar - Updated Nov 2026

Avatar for Alpha Structural, Inc.
Alpha Structural, Inc.
4.6(
241
)
Foundation, Basement or Crawlspace - Waterproofing / EncapsulationBasement Drainage Channels - InstallBasement Drainage Channels - Repair

Serving Diamond Bar, CA and surrounding areas

Approved (Corporate)

In business since 1992

Free estimates

Emergency services offered

"We have a strange leak in our basement that recurs every time it rains. To figure out the potential source, we called Alpha Structural, and the entire team was outstanding from the get-go. Lisa Hunter first took a detailed account of and keen interest in our situation, and then Gary Coffing came to inspect our house. Gary possesses an incredible wealth of knowledge about foundation and structural integrity, and gave us a very fair assessment of what might be happening, and what we could and should try first. Rather than make a hard sell to engage Alpha in a major investigation, he suggested we first try a few simpler solutions, including fixing the grading of our soil leading to the basement as well as our gutters. Perhaps this won't work and perhaps it will, but the point is he gave us a full account of what may be happening and a number of specific things to try before pulling the trigger on a major structural ordeal. A HUGE thank you to Gary and the whole team. We hope it doesn't come to it, but if we do need to go down the route of major structural work, we will absolutely call you again."
Basement Addition
Basement Expansion
Caisson Supported Retaining Wall
Cantilevered Deck Design Build
Deck Expansion and Slope Failure with Retaining Wall

+323

Response time10 hrs
Response rate100%
11 neighbors recently requested a quote
Avatar for Groundworks
Groundworks
3.5(
176
)
Foundation, Basement or Crawlspace - Waterproofing / EncapsulationBasement Drainage Channels - InstallBasement Drainage Channels - Repair

Serving Diamond Bar, CA and surrounding areas

Approved (Corporate)

In business since 1995

Free estimates

Warranties offered

"Roger and his crew of Manuel, Carlos and Josias did everything we asked for and more. Roger answered all of our questions, kept us informed on the status of the project and managed the project extremely well. We definitely made the right decision having Groundworks do our project."
Foundation
Foundation
Foundation
Concrete
Concrete

+16

Response time11 hrs
91 neighbors recently requested a quote
Recommended by38%of homeowners
RSF Construction Inc.
1.0(
1
)
Basement Drainage Channels - InstallBasement Drainage Channels - RepairFoundation, Basement or Crawlspace - Waterproofing / Encapsulation

Serving Diamond Bar, CA and surrounding areas

Approved

In business since 2019

Free estimates

Credit card accepted

RSF Construction Inc. is a leader in providing our customers with the highest quality service in an honest, efficient, and professional way. Our pledge is to create successful relationships with our customers, employees and community by building trust, treating every project with the utmost integrity and exceeding expectations. We look forward to working with you!

Palm Construction, Inc.
5.0(
112
)
Foundation, Basement or Crawlspace - Waterproofing / Encapsulation

Serving Diamond Bar, CA and surrounding areas

In business since 2016

Free estimates

Credit card accepted

It can be a daunting task looking for not only the right contractor for your job but also the right contractor for you. We completely understand what you're going through. We know every customer has different desires, different needs and different schedules. We're not only here to turn your ideas into reality but to make it a memorable experience every step of the way. Call us right now, no matter where you are in the planning process.

Recommended by100%of homeowners
Palm Construction, Inc.
5.0(
90
)
Foundation, Basement or Crawlspace - Waterproofing / Encapsulation

Serving Diamond Bar, CA and surrounding areas

In business since 2016

Free estimates

Credit card accepted

"We worked with Ali (sales manager) and Tony (project manager), who took the time to design a project that made sense for our property and our budget, made a number of suggestions and recommendations and were never pushy or tried to "sell" us on something. The crew really went above and beyond to provide top quality workmanship and overall we were in very good hands. Highly recommended!"
Recommended by100%of homeowners
Avatar for Monarch Concrete Coatings
Monarch Concrete Coatings
4.8(
17
)
Basement Drainage Channels - InstallBasement Drainage Channels - RepairFoundation, Basement or Crawlspace - Waterproofing / Encapsulation

Serving Diamond Bar, CA and surrounding areas

In business since 1985

Free estimates

Credit card accepted

"We had a second story deck that was leaking water into the garage. We got 4 companies to come and give us a quote.  Two of them were cheaper but they seemed as puzzled as we were about what to do and could not guarantee from future problems. The other company suggested rebuilding the entire deck and was way out of budget. Ryan from Monarch Custom Coatings came with a sample that had several layers to waterproof the deck - we were very impressed that he was very knowledgeable and has a lot of experience with this type of work. He and his crew worked very hard, always professional, prompt, courteous, and our deck looks amazing now. We were so happy with them that we hired them again to redo the garage floors. We have had bad experiences in the past with contractors, so we know that finding a good, reliable, and honest one is very hard and rare. We highly recommend Monarch Custom Coatings!"
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+19

Recommended by93%of homeowners
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Basement Waterproofing FAQs, answered by experts

Interlocking garage tiles made with PVC are the most effective for garages with past issues of humidity and flooding because damp concrete is not suitable for paint. Epoxy coating is also water-resistant and can prevent mold buildup. Finally, porcelain tiles are a wonderful option for wet conditions if your budget allows.

Yes, you can enclose your crawl space. Enclosing your crawl space can promote energy efficiency and reduce the risks of pests and mold by limiting factors like humidity. It can also reduce heat loss, which is why doing so for the winter can make your home more comfortable.

Underfloor insulation alone will not cause moisture and mold, but improper installation can. Although the purpose is to seal any drafts, your subfloor still needs ventilation. If you seal the area too tightly and prevent all airflow, this can cause moisture to get trapped. This moisture eventually leads to mold and—if your floors are wood—rotting.

Roughing in and connecting utilities are the hardest parts of finishing a basement, and they’re the parts we typically don’t recommend doing as a DIY project. Unfortunately, your finishing timeline can be extended by weeks while you wait for contractors and inspectors to install electrical wiring, plumbing lines, and heating/cooling equipment and carry out inspections.

Yes, outside leaks can easily cause damage to your home if you don’t have waterproofing measures in place. Regularly check your property for signs of a leak, ensure your home’s landscaping is at least at a 5% slope, your basement windows are sealed, and you have an aligned gutter system to catch rainwater.

The Diamond Bar, CA homeowners’ guide to basement waterproofing services

From average costs to expert advice, get all the answers you need to get your job done.