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TRUSTED BY CORNELIUS, OR HOMEOWNERS

  • Average homeowner rating star icon4.1
    Average homeowner rating
  • Verified reviews icon96
    Verified basement waterproofing services reviews

Find Basement waterproofing pros in Cornelius

Avatar for TerraFirma Foundation Systems

TerraFirma Foundation Systems

13110 SW Wall Street
4.55(
218
)
Approved Pro

TerraFirma Foundation Systems

13110 SW Wall Street
4.55(
218
)
Approved Pro
Customers say: Super punctual
98 local quotes requested
20 years of experience

Thousands of NW homeowners have trusted TerraFirma Foundation Systems to keep their homes safe, dry and stable since 2005. Nearly half of our business comes from referrals or repeat customers. We can help you too! TerraFirma is the NW expert in home foundations, basement and crawl space waterproofing, concrete leveling, and wall stabilization.

"I hired TerraFirma Foundation Systems to level my home, expecting a professional job with clear communication, but the entire experience has been incredibly disappointing and costly. From the start, I hired the company to level the floors in my home, specifically to address a nearly 3-inch dip in my kitchen area, a 13x10 room. Yet after they “completed the job,” I still have a 1.5-inch dip in the center of the kitchen, and a corner of my home/kitchen that sits half an inch higher than it should be (above 0%), creating a full inch rise from the living room to the kitchen. Now they’re saying that leveling the kitchen wasn’t included in the original scope, blaming the remaining dip on my kitchen island and fridge being “too heavy” and lacking proper support—an issue they failed to identify in the initial assessment. To properly address this problem, they’re now asking for an additional $7,500, claiming this work was never part of the original job. This feels like a classic bait-and-switch tactic, and I can’t help but feel taken advantage of. To make matters worse, I discovered that they used an uncalibrated machine during the initial leveling when installing, which raised my house over an inch more than necessary, causing significant damage that wasn’t there before. Partway through the lift, they even asked me to sign a waiver to get my house closer to 0% level, effectively absolving them of any damage caused. The technician stopped mid-lift to show me the damage that was already occurring and warned that more would likely follow if we continued. I agreed to proceed, trusting their assurances and assuming their equipment was properly calibrated. I even pointed out to the technician at the time that it did not look level, and he assured me the machine was correct. Now, they refuse to take any responsibility for the resulting damage, dismissing it as “standard” and providing terms within the contract absolving them—despite them overcorrecting the home. There were also repeated measurement discrepancies, with reports showing one reading and verbal statements/emails suggesting different levels. When I sought clarification, I received vague responses and empty apologies. After all this, and nearly $30,000 invested, my floor remains unleveled. The only resolution TerraFirma Foundation Systems has offered is for me to pay additional money to level the kitchen and to wait for the overcorrected area to “settle naturally”—a process that, according to their technician, could take anywhere from two months to ten years. I hired TerraFirma Foundation Systems to fully level my home, not to leave me with an incomplete job, inconsistent results, and vague promises. If you’re considering foundation work, I strongly recommend looking elsewhere—this company has left me with extensive damage, unexpected costs, and a significant amount of frustration."

Chuck G on November 2024

Thousands of NW homeowners have trusted TerraFirma Foundation Systems to keep their homes safe, dry and stable since 2005. Nearly half of our business comes from referrals or repeat customers. We can help you too! TerraFirma is the NW expert in home foundations, basement and crawl space waterproofing, concrete leveling, and wall stabilization.

"I hired TerraFirma Foundation Systems to level my home, expecting a professional job with clear communication, but the entire experience has been incredibly disappointing and costly. From the start, I hired the company to level the floors in my home, specifically to address a nearly 3-inch dip in my kitchen area, a 13x10 room. Yet after they “completed the job,” I still have a 1.5-inch dip in the center of the kitchen, and a corner of my home/kitchen that sits half an inch higher than it should be (above 0%), creating a full inch rise from the living room to the kitchen. Now they’re saying that leveling the kitchen wasn’t included in the original scope, blaming the remaining dip on my kitchen island and fridge being “too heavy” and lacking proper support—an issue they failed to identify in the initial assessment. To properly address this problem, they’re now asking for an additional $7,500, claiming this work was never part of the original job. This feels like a classic bait-and-switch tactic, and I can’t help but feel taken advantage of. To make matters worse, I discovered that they used an uncalibrated machine during the initial leveling when installing, which raised my house over an inch more than necessary, causing significant damage that wasn’t there before. Partway through the lift, they even asked me to sign a waiver to get my house closer to 0% level, effectively absolving them of any damage caused. The technician stopped mid-lift to show me the damage that was already occurring and warned that more would likely follow if we continued. I agreed to proceed, trusting their assurances and assuming their equipment was properly calibrated. I even pointed out to the technician at the time that it did not look level, and he assured me the machine was correct. Now, they refuse to take any responsibility for the resulting damage, dismissing it as “standard” and providing terms within the contract absolving them—despite them overcorrecting the home. There were also repeated measurement discrepancies, with reports showing one reading and verbal statements/emails suggesting different levels. When I sought clarification, I received vague responses and empty apologies. After all this, and nearly $30,000 invested, my floor remains unleveled. The only resolution TerraFirma Foundation Systems has offered is for me to pay additional money to level the kitchen and to wait for the overcorrected area to “settle naturally”—a process that, according to their technician, could take anywhere from two months to ten years. I hired TerraFirma Foundation Systems to fully level my home, not to leave me with an incomplete job, inconsistent results, and vague promises. If you’re considering foundation work, I strongly recommend looking elsewhere—this company has left me with extensive damage, unexpected costs, and a significant amount of frustration."

Chuck G on November 2024


Avatar for John's Waterproofing

John's Waterproofing

219 Airport Rd
4.30(
240
)
Approved Pro

John's Waterproofing

219 Airport Rd
4.30(
240
)
Approved Pro
Customers say: Super punctual
28 local quotes requested
51 years of experience

Since 1974, John's Waterproofing has been helping the PNW have dry and healthy homes. We specialize in below-grade waterproofing for crawlspaces and basements. In addition to this we also provide radon testing and mitigation, and humidity and mold control. We are proud to offer the best in the industry solutions to your homes waterproofing needs. Cost is determined by the job. CCB#15830 (503) 873-5650 [email protected]

"Chris and Joel were great, they were in and out and our water heater was rewired and sump pump wired in no time at all."

Dawn S on May 2025

Since 1974, John's Waterproofing has been helping the PNW have dry and healthy homes. We specialize in below-grade waterproofing for crawlspaces and basements. In addition to this we also provide radon testing and mitigation, and humidity and mold control. We are proud to offer the best in the industry solutions to your homes waterproofing needs. Cost is determined by the job. CCB#15830 (503) 873-5650 [email protected]

"Chris and Joel were great, they were in and out and our water heater was rewired and sump pump wired in no time at all."

Dawn S on May 2025


Avatar for Pacific Waterproofing & Foundation Solutions, LLC

Pacific Waterproofing & Foundation Solutions, LLC

6404 NW Lincoln Ave
4.92(
6
)
Approved Pro

Pacific Waterproofing & Foundation Solutions, LLC

6404 NW Lincoln Ave
4.92(
6
)
Approved Pro
Customers say: Quality work
58 local quotes requested
13 years of experience

At Pacific Waterproofing, LLC, we take great pride in our experience, expertise, quality and customer service that we provide to meet the consumer's needs. It is our mission to provide excellent workmanship and complete customer satisfaction from start to completion of a project. In order to understand the needs and expectations of our customers, we take great care to work and communicate with every customer in a professional manner. Our reputation is based on service, safety, and quality, regardless of how large or small the job.

"Great work! Communication was rough at times but other than that, highly recommend"

Dan S on April 2025

At Pacific Waterproofing, LLC, we take great pride in our experience, expertise, quality and customer service that we provide to meet the consumer's needs. It is our mission to provide excellent workmanship and complete customer satisfaction from start to completion of a project. In order to understand the needs and expectations of our customers, we take great care to work and communicate with every customer in a professional manner. Our reputation is based on service, safety, and quality, regardless of how large or small the job.

"Great work! Communication was rough at times but other than that, highly recommend"

Dan S on April 2025


Avatar for TerraFirma Foundation Systems

TerraFirma Foundation Systems

13110 SW Wall Street
4.60(
62
)
Approved Pro

TerraFirma Foundation Systems

13110 SW Wall Street
4.60(
62
)
Approved Pro
Customers say: True professional
81 local quotes requested
20 years of experience

Thousands of NW homeowners have trusted TerraFirma Foundation Systems to keep their homes safe, dry and stable since 2005. Nearly half of our business comes from referrals or repeat customers. We can help you too! TerraFirma is the NW expert in home foundations, basement and crawl space waterproofing, concrete leveling, and wall stabilization.

"We needed some posts in our basement replaced with proper footings. TerraFirma was quick to respond and quick to do the work. We are very happy with the result and would recommend."

Nicole C on December 2024

Thousands of NW homeowners have trusted TerraFirma Foundation Systems to keep their homes safe, dry and stable since 2005. Nearly half of our business comes from referrals or repeat customers. We can help you too! TerraFirma is the NW expert in home foundations, basement and crawl space waterproofing, concrete leveling, and wall stabilization.

"We needed some posts in our basement replaced with proper footings. TerraFirma was quick to respond and quick to do the work. We are very happy with the result and would recommend."

Nicole C on December 2024


Avatar for John's Waterproofing Co.

John's Waterproofing Co.

201 Airport Road
4.74(
47
)
Approved Pro

John's Waterproofing Co.

201 Airport Road
4.74(
47
)
Approved Pro
Customers say: Quality work
Recommended by 95% of Angi customers
Recommended by 95% of HomeAdvisor customers
405 local quotes requested

John's Waterproofing Co. is the premier waterproofing company serving in Oregon and southern Washington for almost 4 decades. We Specialize in Basement and Crawlspace Waterproofing and Repairs, we offer free inspections and estimates along with caring customer service. Contact our office today for your waterproofing needs!

"No."

Tracy W on January 2025

John's Waterproofing Co. is the premier waterproofing company serving in Oregon and southern Washington for almost 4 decades. We Specialize in Basement and Crawlspace Waterproofing and Repairs, we offer free inspections and estimates along with caring customer service. Contact our office today for your waterproofing needs!

"No."

Tracy W on January 2025


Avatar for Crawlspace Masters, Inc.

Crawlspace Masters, Inc.

2455 NW Nicolai St Suite B-014
4.90(
79
)
Approved Pro

Crawlspace Masters, Inc.

2455 NW Nicolai St Suite B-014
4.90(
79
)
Approved Pro
Customers say: Quick response
22 local quotes requested
13 years of experience

Dillon Rivera and Harlan Gross grew up together in the Pacific Northwest and quickly realized that they made a great team in business. The only issue was finding something that combined both of their passions. As the years passed, Dillon climbed the ladder at a restoration company to become the General Manager, while Harlan took interest in masonry and eventually got into a managerial role in his field. Eventually they both realized that they had the skills and drive necessary to go into business together in restoration and the rest is history. Restoration combined those two passions: helping people and creating a great product. They had observed all sorts of service practices from various trades including masonry, construction, remodeling and more. The main lesson they learned is: It's not worth it in the short or long run to not provide superb service to the customer.

"Royal was very polite and kept things clean and worked very hard "

Pete B on September 2025

Dillon Rivera and Harlan Gross grew up together in the Pacific Northwest and quickly realized that they made a great team in business. The only issue was finding something that combined both of their passions. As the years passed, Dillon climbed the ladder at a restoration company to become the General Manager, while Harlan took interest in masonry and eventually got into a managerial role in his field. Eventually they both realized that they had the skills and drive necessary to go into business together in restoration and the rest is history. Restoration combined those two passions: helping people and creating a great product. They had observed all sorts of service practices from various trades including masonry, construction, remodeling and more. The main lesson they learned is: It's not worth it in the short or long run to not provide superb service to the customer.

"Royal was very polite and kept things clean and worked very hard "

Pete B on September 2025


Avatar for Pacific Waterproofing and Foundation Solutions LLC

Pacific Waterproofing and Foundation Solutions LLC

6404 Lincoln Avenue
5.00(
1
)

Pacific Waterproofing and Foundation Solutions LLC

6404 Lincoln Avenue
5.00(
1
)
Free onsite estimate

Trusted by thousands of homeowners in the Pacific Northwest for expert waterproofing, crawl space repair and foundation repair. At Pacific Waterproofing, LLC, we take great pride in our experience, expertise, quality and customer service that we provide to meet the consumer's needs. It is our mission to provide excellent workmanship and complete customer satisfaction from start to completion of a project. In order to understand the needs and expectations of our customers, we take great care to work and communicate with every customer in a professional manner. Our reputation is based on service, safety, and quality, regardless of how large or small the job.

Trusted by thousands of homeowners in the Pacific Northwest for expert waterproofing, crawl space repair and foundation repair. At Pacific Waterproofing, LLC, we take great pride in our experience, expertise, quality and customer service that we provide to meet the consumer's needs. It is our mission to provide excellent workmanship and complete customer satisfaction from start to completion of a project. In order to understand the needs and expectations of our customers, we take great care to work and communicate with every customer in a professional manner. Our reputation is based on service, safety, and quality, regardless of how large or small the job.


NW Quality Inc

No reviews yet

NW Quality Inc

No reviews yet
Free onsite estimate

NW Quality Inc. Been in business for 20yrs. We do Stucco, Stone, and waterproofing decks as well as patios, landings, balconies. Also work with epoxy. We mainly use WestCoat products for our waterproofing, texture coats, and epoxy. Stucco Eifs, and conventional. Veneer stone as well as Natural.

NW Quality Inc. Been in business for 20yrs. We do Stucco, Stone, and waterproofing decks as well as patios, landings, balconies. Also work with epoxy. We mainly use WestCoat products for our waterproofing, texture coats, and epoxy. Stucco Eifs, and conventional. Veneer stone as well as Natural.


Avatar for Octopus Project Management LLC

Octopus Project Management LLC

12219 Sw Main St
4.77(
22
)

Octopus Project Management LLC

12219 Sw Main St
4.77(
22
)
Customers say: Quality work
Recommended by 95% of Angi customers
Recommended by 95% of HomeAdvisor customers

Octopus Project Management LLC. is a Disaster Reconstruction firm focused on mitigation and rebuilding of residential and commercial buildings undergoing the restoration claims process. We are General contractors able to take on a multitude of different types of home projects. our project minimum is around $350 plus materials as a standard trip charge and increases hourly for smaller projects. Estimates are free and can typically be provided same day.

"Amazing customer service, did exactly what I needed done!"

Sidney S on June 2025

Octopus Project Management LLC. is a Disaster Reconstruction firm focused on mitigation and rebuilding of residential and commercial buildings undergoing the restoration claims process. We are General contractors able to take on a multitude of different types of home projects. our project minimum is around $350 plus materials as a standard trip charge and increases hourly for smaller projects. Estimates are free and can typically be provided same day.

"Amazing customer service, did exactly what I needed done!"

Sidney S on June 2025


One Speed Services

22050 BOONES FERRY RD NE
No reviews yet

One Speed Services

22050 BOONES FERRY RD NE
No reviews yet
7 years of experience

One Speed Services is your one-stop-shop for indoor air quality solutions. We provide air duct cleaning, dryer vent cleaning, mold remediation, crawl space restoration, attic insulation, drainage correction, HVAC system servicing and installation. We provide free onsite evaluations.

One Speed Services is your one-stop-shop for indoor air quality solutions. We provide air duct cleaning, dryer vent cleaning, mold remediation, crawl space restoration, attic insulation, drainage correction, HVAC system servicing and installation. We provide free onsite evaluations.

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Basement Waterproofing questions, answered by experts

Yes, you can add a bathroom to an unfinished basement, but you’ll want to take proper precautions if doing so. As with any bathroom addition, you’ll need to make sure that it’s approved by local building authorities first. With unfinished basements, you especially need to keep an eye on proper ventilation practices.

It is better to have a crawl space that is tailored to the outside temperature, your needs, and the season. For example, it is much better to have a vented space when it’s very hot outside and your AC bills are sky-high. Conversely, when the temperature drops and humidity rises, it is almost always better to have your vents shut and covered if possible.

Rigid foam insulation boards are one of the best insulation materials for crawl spaces. This material insulates the home well, resists water damage, and won't settle like fiberglass or cellulose. Closed-cell spray foam insulation is another effective insulation that both seals the air and provides excellent thermal protection for hard-to-reach spaces like crawl spaces.

The only real negative when encapsulating a crawl space is that the cost is high. It can cost several thousands of dollars to do this project. However, it protects your house and those in it by providing an energy-efficient space instead of one that frequently pools moisture and causes damage through mold growth in your home. While less common, another disadvantage could be encapsulation making access to pipes and electrical slightly more complicated in certain crawl spaces.

You don’t always need to install a dehumidifier in your encapsulated crawl space, but it might be a good idea in certain instances. If you notice obvious signs of condensation, mold, or musty smells permeating from your crawl space, a dehumidifier can help. It’s ideal for homes in humid areas.

In a worst case scenario, structural damage like rust on metal beams, rotting wood, and swelling on doors and windows can signal moisture problems that would benefit from a dehumidifier.

The Cornelius, OR homeowners’ guide to basement waterproofing services

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

What do you need done? We’ll find top pros.
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