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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
87 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!"
Additional Photos
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Additional Photos
Additional Photos

+19

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

Yes, usually you will need some kind of vapor barrier on the exterior walls when the framing is attached to concrete and masonry surfaces.

A crawl space encapsulation isn’t always necessary, but it’s a wise choice, especially if you live in an area that sees a lot of precipitation. Sealing a crawl space not only reduces damage caused by moisture, mold, and pests, but it also increases your home’s value. It can also save you money by reducing energy bills and avoiding costly repairs for structural or foundation damage.

Yes, water and water vapor can seep through cracks in your basement floor, which means you should address all basement floor cracks, even if they don’t indicate structural issues. Sealing settling cracks and shrinkage cracks is a good idea to keep water and moisture outside where it belongs. Doing so can improve your indoor air quality, reduce the risk of mold growth, make your home more comfortable, and help prevent pest infestation.

Installing a bathroom in a basement isn’t a project for most homeowners. Many parts—plumbing, electricity, and carpentry—go into this project, each requiring expert-level knowledge and tools. One miscalculation can lead to very expensive repairs. Plus, some homeowner’s insurance might not pay for damages caused by a homeowner DIYing this project. You can protect yourself by allowing the pros to complete this job for you. 

You can DIY basement waterproofing in some ways to help save on the overall costs. If your basement isn’t experiencing a lot of water but is noticeably humid, you can try running a dehumidifier that will pull the excess water out of the air. If you notice water leaking due to outdoor drainage issues, you can add downspout extensions to keep rainwater away from your home. 

However, if the problem is more severe and requires a more extensive solution, it’s best to call a basement waterproofing professional to assess the treatment you need and install waterproofing safeguards properly. Since keeping water out of your basement is important, ensuring this job is done correctly the first time is best.

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.