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Best basement waterproofing pros near Sullivan, NH

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Top-Rated Basement waterproofing pros in Sullivan - Updated Nov 2026

Avatar for Northern Basement Systems
Northern Basement Systems
4.6(
21
)
Foundation, Basement or Crawlspace - Waterproofing / EncapsulationBasement Drainage Channels - InstallBasement Drainage Channels - Repair

Serving Sullivan, NH and surrounding areas

Approved

In business since 2010

Free estimates

Warranties offered

"Paul Swann evaluated our foundation problem and referred us to an engineer who provided a detailed repair plan. Unfortunately, the nature and scope of the proposed repair plan was outside the parameters of what Northern Basement System's themselves could provide. We appreciated their honesty and have been looking for a contractor to take on the project."
Additional Photos
Additional Photos
Additional Photos
Additional Photos
Additional Photos

+25

Response time1 day
3 neighbors recently requested a quote
Recommended by88%of homeowners
Avatar for LeBlanc Basement Waterpoofing, LLC
LeBlanc Basement Waterpoofing, LLC
5.0(
3
)
Foundation, Basement or Crawlspace - Waterproofing / Encapsulation

Serving Sullivan, NH and surrounding areas

Approved

In business since 2007

Free estimates

Emergency services offered

"I was impressed with his knowledge and professionalism. He installed a French drain system with a vapor barrier on the walls. He prepped the area to protect our belongings, made sure everything was cleaned up after the end of each day, and provided exceptional service and quality. I would highly recommend him!"
Ion sump pump
Airtight solid sump cover
Ashburnham, MA.
Ashburnham, MA.
Ashburnham, MA.

+28

Response time1 day
8 neighbors recently requested a quote
Recommended by100%of homeowners
Avatar for Green Home Solutions of North Central MA
Green Home Solutions of North Central MA
4.8(
13
)
Foundation, Basement or Crawlspace - Waterproofing / Encapsulation

Serving Sullivan, NH and surrounding areas

Approved

In business since 2021

Warranties offered

Credit card accepted

"Kenson was able to come in and do the work quietly as I was working from home. He explained all the steps and the possible remediation. Paying by cc did have a heavy charge, but otherwise everything was awesome."
Attic Mold Remediation - Fitchburg, MA
Mold Contamination in Attic
Living Room- Mold remediation - Lowell MA
Living Room Mold Remediation - Lowell, MA
Attic Mold Remediation - Derry, NH

+11

Response time12 hrs
Response rate90%
43 neighbors recently requested a quote
Avatar for Freedom Framing and More, LLC
Freedom Framing and More, LLC
4.3(
14
)
Foundation, Basement or Crawlspace - Waterproofing / Encapsulation

Serving Sullivan, NH and surrounding areas

Approved

In business since 2014

Free estimates

Warranties offered

"I had a great experience with Freedom Framing! Matthew was very easy to work with and did a great job for a great price! Matthew is not only a great carpenter he is a very good project manager, ensuring the supporting contractors needed to complete the work arrived on time and performed top quality work. I would strongly recommend him for any construction work needed. I will be calling Matthew for the next project on my list! Excellent job Matthew! Thank you very much!"
Before
During
Wrapping up
Finished
Prep

+34

Response time2 days
Response rate95%
Recommended by84%of homeowners
Avatar for Basement Solutions LLC
Basement Solutions LLC
New to Angi
Foundation, Basement or Crawlspace - Waterproofing / EncapsulationBasement Drainage Channels - InstallBasement Drainage Channels - Repair

Serving Sullivan, NH and surrounding areas

Approved

In business since 2025

Free estimates

Warranties offered

We pride our company on reliability, integrity and quality work. We are experts in our trade. We look forward to earning your business! We specialize in concrete crack repair and injections, basement waterproofing, sump pump installations, basement and egress window installations, crawlspace repair, moisture control, foundation repair and so much more.\nCall us today for a free estimate.

Egress
Egress
Egress
Sump Pump
Perimeter System

+4

11 neighbors recently requested a quote
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Basement Waterproofing FAQs, answered by experts

Whether to waterproof your basement from the interior or exterior depends on several factors, including your budget.

Exterior waterproofing is generally considered the superior method because it stops water at the source, preventing it from seeping into and damaging your basement walls. This approach offers the most protection, making it ideal if you use your basement for storage.

By contrast, interior waterproofing is often less expensive and requires less labor because the area is more accessible.

For maximum protection against water leakage and moisture, applying waterproofing measures to both the inside and outside is the best solution. However, if you must choose only one, stopping water from the outside is the most effective approach to preserve your foundation and prevent damage.

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.

Topical sealers adhere to the surface of concrete to create a protective layer. In many cases, this is all you need for concrete that sees light to moderate traffic, such as your basement. Penetrating sealers, on the other hand, bond with the free lime in the top layer of concrete to form calcium silicate, which prevents liquid from passing through. This type of sealer protects the surface from water, oil, and gasoline spills.

Although the two terms are closely related and often used interchangeably, pier and beam foundations and crawl spaces are different things. A pier and beam foundation is made up of concrete piers and wooden beams and creates a space under the home known as a crawl space. There are several types of foundations that create crawl spaces, often collectively known as “crawl space foundations,” but the crawl space itself is separate from the foundation. 

The best way to ensure the ground next to your home’s foundation drains properly is to divert water away from it as much as possible. While a flood wall can stop water from entering the house, gutters and spouts can help direct rainwater and melting snow away from the foundation. Keep your gutters as clear as possible from dead leaves and other yard debris so they can effectively divert water from your house. Add extenders to the spouts so the water runs out and away from your home, not into the surrounding soil.

The Sullivan, NH homeowners’ guide to basement waterproofing services

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