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Find Basement remodelers in Portsmouth

Avatar for Total Basement Finishing, a Blackdog Affiliate
Total Basement Finishing, a Blackdog Affiliate
5.0(
1
)

Angi Approved

In business since 1989

Free estimates

Warranties offered

Total Basement Finishing, A Blackdog Affiliate serves the Greater Lowell area of Massachusetts and New Hampshire with basement finishing and basement remodeling. Finishing your previously unused basement gives you additional space in your home and so much more. It offers you a rare opportunity to exploit your creative side through the design process. And ultimately, you will transform a dark, uninviting space into a room that adds value and comfort to your home, making it an integral part of your family’s daily life.

Avatar for Envy Homes, LLC
Envy Homes, LLC
4.8(
2
)

Angi Approved

In business since 2021

Warranties offered

Customers say: Terrific value

"They showed up on time each day, were very knowledgeable of the work they performed. Showed up for the quote when we scheduled the first meeting and we were very impressed with the overall experience. The deck they built was spot on and perfect for our needs. They did make some recommendations as to how it would look and work better for us and we went with their decisions and are so happy and impressed. They were very neat about their work and very easy to talk with. I would never use anyone else, and HIGHLY RECOMMEND them for whatever you need. So great to work with."
Recommended by100%of homeowners
Ram Construction & Home Remodeling
4.1(
17
)

Angi Approved

In business since 1979

Free estimates

Emergency services offered

"We hired Rich with RAM Construction to complete a major renovation to our property. With my husband being a contractor himself but having no time to do the work, this was a big step to take on our behalf and we needed a contractor we could trust to show up and complete this major renovation. Rich took the job on knowing full well what challenges may exist with working at another contractorâ s home. Rich was completely open to my husbandâ s suggestions as well as being able to provide his own ideas on how to complete the project. Even though we had a contract Rich has been very accommodating with allowing us to veer outside of the project specs. Rich has been great to work with and we recommend him 100% to anyone who may be looking for a great Contractor."
Recommended by76%of homeowners
Avatar for Owens Corning Basement Finishing System
Owens Corning Basement Finishing System
4.8(
342
)

Angi Approved

Super Service Award Winner

In business since 1990

Free estimates

Customers say: True professional

"Very good experience, they handled all permits and kept me updated every step of the way. Always arrived on time, very professional, amazing craftsmanship and when they were done they left a perfectly clean area. Would definitely recommend"
131 neighbors recently requested a quote
Recommended by78%of homeowners
Avatar for Remodel or Renew Home Improvement
Remodel or Renew Home Improvement
4.8(
256
)

Angi Approved

In business since 2018

Free estimates

Emergency services offered

"Ill never use Angi again. There was no way to contact my installer. They never showed up for my job. I say call a local pro. At least they shoe up and appreciate your business. "
412 neighbors recently requested a quote
Recommended by91%of homeowners
Avatar for Total Basement Finishing
Total Basement Finishing
4.0(
5
)

Angi Approved

In business since 1989

Free estimates

Warranties offered

"The company (Black Dog) was hired to expand the bathroom and part of the basement renovation. The project started in October 2020 and it is still going through May 2021 with an unclear restart date after 2 no shows. It was promised to finish by Christmas. The company used 2 different colors of grout in the same room. They are planning to come back and redo it, waiting for 2 months now. They do not want to spend time on fixes. Leakage around the shower was noted, they promised to contact the subcontractor, but I have not heard from them yet. There are minor things missing, would pay attention to their contract as they may not do things like shelves installation as originally discussed. They seemed professional on initial evaluation and at the beginning, but now I am regretting that I hired them."
12 neighbors recently requested a quote
Recommended by80%of homeowners
Avatar for HONEYCOMB CONSTRUCTION, LLC
HONEYCOMB CONSTRUCTION, LLC
4.9(
7
)

Angi Approved

In business since 2022

Free estimates

"Honeycomb helped save our house. As they were replacing our deck, they discovered rot and quickly removed and replaced all the bad material. They also discovered that we had a termite infestation. The issue was in the structure of the house. They assured us everything would be fine and efficiently dispatched all the rot and talked us through next steps with detailed recommendations, involving other contractors. The additional charge to remove the rot was minimal and I would have gladly paid 10x for the security of having a safe house. And just look at how beautifully it turned out. The photos really don't do it justice, when you get to sit out there enjoying a coffee in the morning or actually having a family gathering. It is such a game changer meeting space. Also, and it might seem like a little thing, but its the details that matter. It was really hard for me to get on my deck as a physically handicapped person. Taylor made it easy for me to go outside alone. I love you guys 11/10"
1 neighbors recently requested a quote
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FAQs for basement remodeling projects in Portsmouth, NH

Finishing a basement turns unused square footage into livable space and returns up to 70% of what you spend when you sell your home. Beyond that resale boost, you gain a playroom, home office, or guest suite you can start enjoying right away. That mix of daily comfort and solid return on investment (ROI) makes basement finishing one of the smartest upgrades you can tackle.

In some parts of the country—especially lots on swamps, high water tables, or other wetlands—local codes prohibit basements. Saturated soil puts constant pressure on foundation walls and lets water seep in faster than any sump pump can handle. 

If your property sits on waterlogged ground, building on a slab or crawl space is often safer, more affordable, and code-compliant.

Most basements wrap up in four to eight weeks. Framing takes three to five days, with electrical and plumbing rough-ins following over the next week. Add five days for drywall, two to three for flooring, and another week for paint, trim, and punch-list items. 

Delays can happen if materials run late or your contractor’s calendar is packed, so build in a little cushion when you plan.

Whether a finished basement counts toward your home’s official square footage depends on local rules. Many areas only include below-grade space if it has code-approved egress, fully finished walls, ceilings, and floors, plus consistent heating. 

Check with your local assessor or building department before you start; meeting those standards can affect taxes, appraisals, and resale value.

Building codes require a checklist: dedicated heat and electrical service, a code-approved stairway, and at least one egress window or exterior door. Walls, ceilings, and floors must be fully finished and meet insulation, ventilation, and fire-separation standards. If you add a bedroom, you’ll also need a closet, proper clearances, and safe exits. If you change the layout later, be ready to update the space so every new room still meets today’s code.

The Portsmouth, NH homeowners’ guide to basement remodelings

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