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Crawl Space vs Basement: Which Do You Need?



V Susan
Hi! I'm Susan. I am passionate about woodworking, general DIY and home improvement. If you'd like to connect with me or talk about something you like at mellowpine, drop me a mail at susan@mellowpine.com


Crawl Space vs Basement

Crawl spaces and basements lie beneath a home, creating a hollow space between the ground and the first floor.

A crawl space is a narrow gap between the ground and the house. It is usually between 18 inches and 3 feet in depth, making it impossible to stand upright. Basements are larger and pricier, with 8-foot ceilings. They are essentially standard rooms, albeit entirely or partly below street level.

What is the Difference Between a Crawl Space and a Basement?

The following are the differences between a crawl space and a basement.

ConsiderationCrawl SpaceBasement
UtilityConceal basic utilities (such as plumbing and wiring), and provide limited storageAct as extra rooms or storage alongside concealing basic utilities
HeadroomSufficient headroom to crawl in; typically 18″ to 3 ft. heightSufficient headroom to stand in;typically 8ft. height 
AccessAccessible only from the outside, inconvenient tight spaceComfortable access from inside the house
SecurityOpen to the elements when left unfinishedAlways enclosed on all sides
Disaster SafetyBetter protection from floodsEmergency shelter during hurricanes and tornadoes
CostSignificantly cheaper whether finished or unfinishedExpensive to construct but add to the resale value
FlooringUnfinished, uneven dirt flooring is commonConcrete slab acts as flooring
Maintenance Vulnerable to dampness, mold, and pests ranging from termites to raccoonsSusceptible to dampness, mold, insects, and small rodents
Damage detectionLess visibility, harder to notice damageBetter accessibility and visibility, easier to detect damage
Ideal forSlopes and flood zonesRegions of heavy frost and storms
Crawl Space vs Basement


Crawlspace vs Basement
Crawlspace vs Basement

The most visible difference between crawl spaces and basements is their headroom.

Generally, crawl spaces have a limited headroom about 18 inches to 3 feet in height, whereas basement are larger, with a minimum height of 7 to 8 feet.


Home Theatre in a Basement
Home Theatre in a Basement

Crawl spaces are relatively cramped, which restrains their use primarily to housing ductwork, wires, and other basic utilities.

Regarding structural safety, crawl spaces protect the house from floods by raising the first floor from the ground.

In contrast, basements are potential extra living spaces.

Their function can range from laundry rooms to fully-fledged home theaters.

Since they’re underground and often windowless, basements protect occupants from falling debris during tornadoes and hurricanes.

Construction and Maintenance 

Being large and multipurpose makes basements more expensive to build.

Since they are easy to enter and inspect, the maintenance of basements and anything placed inside them is a breeze.

On the other hand, crawl spaces are significantly cheaper to construct.

The constrained size makes it inconvenient to enter crawl spaces to inspect and address problems such as mold or dampness.

Which is Better: a Crawl Space or a Basement?

Extremely dry ground and bedrock are challenging to excavate.

Shallow crawl spaces are preferable in these cases. 

Additionally,if the foundation has to contend with soils that slide, a high water table, or the risk of floods, crawl spaces are safer than basements.

In cold regions, however, basements are a smarter choice.

Building foundations need to be dug deeper than the depth to which the ground freezes.

Since this necessitates much excavation, spending a little extra on developing a full basement is preferred.

Climatic and ground conditions aside, even code-compliant crawl spaces are often highly cramped, damp, and inconvenient for repair and storage compared to basements.

Basements, though more expensive, provide a safer and more accessible environment.

Their concrete flooring prevents moisture, pests, and radon ingress.

Property values also favor the conventional choice.

A house with a basement can be valued less if it looks different from all the surrounding homes featuring crawl spaces, and vice versa.

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The Cost of Construction: Crawl Space vs Basement

Constructing a moisture-proof crawl space generally costs about $13 per square foot (including labor and material costs).

An uninsulated dirty crawl space can cost less at about $7 per square foot.

Existing crawl spaces can be refurbished later to protect them from moisture and pests.

It takes about $5,500 to waterproof the average crawl space.

The final price of waterproofing varies with the extent of protection provided.

Thin plastic “vapor barriers” that block moisture from the soil cost less than a dollar per square foot.

Complete encapsulation involves robust sealing and dehumidifiers.

This can cost about $3-$7 per square foot.

Basements are costlier at about $10-$25 per square foot for an unfinished basement,whereas finished basements can range from $25 to $100 per square foot.

Recent estimates pegged the average cost of finishing a basement at $18,400.

The actual cost varies with geographic conditions and soil, materials, interior design, and basement shape with irregular shapes increasing the price.

Waterproofing a Crawl Space and a Basement

The first step in waterproofing is ensuring proper drainage to protect the foundation by directing water toward the edges of the house’s perimeter.

When the water table is high or rainfall is plentiful, sump pumps push the water out before it finds its way into the crawl space or basement.

Sealing the walls and floor comes next.

Polyethylene vapor barriers are used to line crawl spaces on all sides.

In basements, concrete floors are coated with waterproof resins. 

You can also use dehumidifiers to ensure the inside remains dry.

Proper waterproofing goes a long way as it prevents mold, staining, and dampness.

Sealing basements and crawl spaces improves their energy efficiency, protects homes from pests, and help avoid radon intrusion (a colorless and odorless carcinogen) from the ground.

Can a Crawl Space be Converted into a Basement?

Can a Crawl Space be Converted into a Basement?
Can a Crawl Space be Converted into a Basement?

While the final answer is subject to ground conditions, crawl spaces can sometimes be turned into basements.

This process begins with providing temporary support at the foundations.

The crawl space is then deepened by either raising the house level or laying new foundations beneath the existing ones.

Insulating and waterproofing the resulting basement follows.

Crawl space conversion is best done in consultation with a professional since it involves changing the structure’s foundations.

The whole process costs about $50 per square foot on average.

Crawl Space and Basement: Uses

Crawl spaces and basements lift the house off the ground, making insulation easier.

When built up to code, they also protect the house’s structural elements during floods and earthquakes.

Basements can act as additional living space and emergency shelter during hurricanes.

Both allow the homeowner to neatly tuck ductwork out of sight while maintaining access for repair and maintenance.

Ample storage space is another benefit of basements and crawl spaces with sufficient headroom.

Finishing the Crawl Space and the Basement

Waterproof and insulated (“encapsulated”) crawl spaces offer better storage conditions and make heating systems more energy-efficient.

When crawl spaces are insulated, mold growth and the entry of toxic gases from the ground are reduced.

This improves the quality of air supplied by the ventilation ducts passing through crawl spaces.

An unfinished basement generally has flooring, walls, minimal utilities, and waterproofing.

It may serve as a convenient workshop or storage area, but little else.

Making an unfinished basement livable involves finishing it by adding drywall, plumbing, heating, and electricity, alongside structural changes such as adding windows.

Finished basements are handy for families that require extra room for older children or guests, or they can be rented out.

Some prefer to have semi-finished basements to avoid paying extra taxes.

Alternatively, partially or fully finished basements can be turned into home gyms, media rooms, and the like.

As the increased livable space raises the house’s resale value, finished basements are estimated to provide a return on investment of about 70%. 

Maintenance of a Crawl Space and a Basement

Leakage in the Basement
Leakage in the Basement

Inspecting crawl spaces and basements every six months is ideal, especially after experiencing wet or cold weather.

Moisture can creep in during rain, and the warmth of these spaces attracts pests in winter.

Mold also accumulates quickly in these parts of the house, so the source of any dampness or musty smell should be swiftly located and caulked.

Signs of pest infestations include rodent and insect droppings.

Fine sawdust from unidentified sources or tiny holes in the surface of wood indicates an infestation of carpenter ants.

Certain termites leave ‘mud tubes’ or paint blisters along the walls.

Monitoring energy and water consumption is also necessary.

Unexpected surges can result from leaks or other issues in the basement or crawl space.

Building a basement knee wall will prevent moisture from entering your basement.

Is it Preferable to Have a Crawl Space or a Slab?

Slab Foundation
Slab Foundation

Concrete slab foundations crack or get flooded in earthquake-prone regions, flood zones, and cold climates where the ground freezes.

They break when the soil underneath shifts or tree roots penetrate them.

Homes in such situations require the extra height provided by crawl spaces.

Building an uneven crawl space on slopes is easier than leveling the ground for a slab.

In friendly ground conditions, the choice between slabs and crawl spaces comes down to cost, maintenance, and accessibility.

Due to their cheaper and faster construction, foundation slabs are perfect for budget-conscious homeowners.

Prices for slabs begin at around $4 per square foot.

They are easier to maintain and come with minimal risk of pest infestation.

Heating is also more energy efficient in these homes.

Additionally,homes built atop slabs do not require steps, unlike those lifted off the ground by crawl spaces.

For this reason,slab foundations are preferred by inhabitants using mobility aids or families with young children.

However,properly sealed crawl spaces are better for future remodeling, maintenance, and storage.

Slabs do not provide easy access to ductwork, and water and gas lines are often embedded in the foundation slab.

Changes to HVAC, electrical, or plumbing systems are more expensive when they involve cutting the slab.

Furthermore,aesthetic concerns include conforming with other homes in the neighborhood.

Being the only house with a crawl space in a community that prefers slab foundations (or the other way around) impacts resale value.

Personal preference in flooring comes into play as well.

Concrete slabs are harsher on the feet than the soft wooden rafters that make up the floor above crawl spaces.

Frequently Asked Questions(FAQ)

Is it Worthwhile to Purchase a Home with an Unfinished Basement?

An unfinished basement is more affordable than a finished basement.

The lack of carpeting and wallpapering makes it easier to inspect the house and detect problems before signing the contract.

Unfinished square footage is also taxed less.

Does Finishing My Basement Need a Building Permit?

Rules vary between municipalities, but most require permits to expand an existing structure or undertake major heating, electrical, and plumbing works.

Finishing a basement involves many such changes.

Obtaining a permit requires filling out an application and submitting the basement or crawl space plans.

Finishing Crawl Spaces and Basements: DIY it or Hire Out?

DIY-ing the finishing of a basement or crawl space needs a wide range of skills and pricey tools.

While laying the flooring or painting can be taken up individually, others may still require professionals.

Wiring, plumbing, waterproofing, and major retrofitting of basements are best left to professionals to ensure the final result is up to code.

V Susan
Hi! I'm Susan. I am passionate about woodworking, general DIY and home improvement. If you'd like to connect with me or talk about something you like at mellowpine, drop me a mail at susan@mellowpine.com