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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

"Very honest, great at communicating everything that was going to happen and how long, very helpful and accommodating. Very professional and made me feel comfortable! They showed up on time and did a great job!"
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 Groundworks
Groundworks
4.6(
26
)
Foundation, Basement or Crawlspace - Waterproofing / EncapsulationBasement Drainage Channels - InstallBasement Drainage Channels - Repair

Serving Sullivan, NH and surrounding areas

Approved (Corporate)

In business since 1996

Free estimates

Warranties offered

"Joe,James and Bobby did an excellent job replacing the sump pump And drains. My husband and I were so impressed with their abilities and how hard working they were. I would highly recommend Ground works Manchester to anyone who needs the same work done. Thanks to all the gentlemen for their professionalism and work ethic"
Foundation
Foundation
Foundation
Basement
Basement

+16

Response time12 hrs
172 neighbors recently requested a quote
Recommended by56%of homeowners
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 Four Seasons Masonry And ChimneyConstruction
Four Seasons Masonry And ChimneyConstruction
5.0(
3
)
Foundation, Basement or Crawlspace - Waterproofing / Encapsulation

Serving Sullivan, NH and surrounding areas

Approved

In business since 1969

Free estimates

Emergency services offered

"Excellent Work on My Fieldstone Foundation! I couldn't be happier with the work Four Seasons Foundation Repair did on my fieldstone foundation. They did a great job, and I'm extremely pleased with the results. Their workmanship and attention to detail really showed. It's not easy working with older fieldstone foundations, but they handled the job beautifully. I highly recommend Four Seasons Foundation Repair to anyone looking for quality foundation work. Thank you for a job well done!"
Chimney repairs
Chimney repairs
Chimney repairs
Chimney repairs
Chimney repairs

+3

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

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

Proper basement ventilation is very effective at reducing humidity. Without enough ventilation, your basement is prone to mold and moisture damage. Your basement should have as much natural ventilation via windows and doors as possible, and if your budget allows, you should also consider installing an ERV system to keep basement humidity levels at bay.

Several factors can impact the cost of waterproofing your basement. Some of the most common cost factors include:

  • Location

  • Square footage

  • Cause of the water leak

  • Type of foundation

  • Accessibility

  • Waterproofing method

  • Materials

  • Contractor experience and availability

  • Engineering reports, if needed

  • Structural and other repairs

  • Permits

When doing any type of project involving mold, it's important to wear the right protective gear. You'll want an N-95 or KN-95 mask to keep yourself from inhaling mold spores, which can be irritating or trigger an allergic reaction in people with weakened immune systems. You'll also want to wear protective eyewear and gloves to limit your contact with mold.

Water leakage through window openings is much more common in older homes, but it can also create issues with window frames that are improperly installed. If left unattended, water buildup can cause damage to surrounding fixtures, lead to harmful mold, and compromise the architectural integrity of your home. The potential damage that a water leak poses makes investing in weather- and water-proofing your window frames entirely worthwhile.

Yes, it is possible to over-dehumidify a house by removing too much moisture from the air. This can create an overly dry environment that negatively affects those with respiratory or skin issues, and may cause your skin, hair, and sinuses to feel dry. However, this is unlikely to happen with most modern dehumidifiers, as they are equipped with moisture sensors and adjustable settings. These features allow the unit to pause automatically when the desired humidity level is reached, preventing the air from becoming uncomfortably dry. In contrast, older or more basic dehumidifiers left running for too long could potentially over-dry the air. To avoid this, aim for a balance between removing excess moisture and maintaining a comfortable environment. You can often monitor your home's humidity levels using a modern thermostat for guidance.

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.