Cast iron bathtub weight is the first question every homeowner should know about before buying, moving, or installing a tub. This guide covers everything you need to know about cast iron tubs, freestanding cast iron and alcove cast iron models, including exact weight of a cast iron tub (240–500 lb empty), how water and a bather can push totals past 600 lb, and whether your floor can support it (40 pounds per square foot). We compare acrylic tub vs cast iron tub, enameled steel tubs, and different bathtub materials, discuss durability, heat retention, and enamel coating on cast iron. Learn how to clean, maintain, or even remove an old tub, plan a bathroom renovation, and ensure safe installation for bathtub upstairs or clawfoot tubs. Avoid surprises on install day by understanding tubs are very heavy, proper floor support, and which type of bathtub is right for your home.
TL;DR: Key Numbers
Quick facts
Empty weight:
- 240–500 lb typical cast iron bathtub weight (Source: Prudent Reviews, 2025, Average Cast Iron Bathtub Weight (With 15 Examples))
- Alcove 60": about 320 lb
- Freestanding 60–75": average ~385 lb (large models up to 500 lb)
- Petite 45–55": about 250 lb
Water adds:
- 1 gallon ≈ 8.34 lb
- 32 gal ≈ 267 lb; 82 gal ≈ 683 lb
Example totals:
- 320 lb tub + 32 gal water ≈ 587 lb (before adding a bather)
- 500 lb tub + 82 gal water ≈ 1,183 lb (before adding a bather)
Floor load:
- Typical residential design live load: 40 pounds per square foot (psf) (Source: HUD User, 2017, Residential Structural Design Guide)
- A 5’×10’ bath floor designed for 40 psf has a uniform live load capacity of about 2,000 lb
Comparisons:
- Enameled steel tub: 150–200 lb
- Acrylic tub (60"): about 109 lb
What this means to you
- Verify joists and spans, especially for upper floors or older homes.
- Plan the delivery path and team. Most cast iron tubs need 3–4 helpers or lift equipment.
- Budget for reinforcement if choosing large freestanding or clawfoot models or if your floor shows any weakness.
Visuals & tools
- At-a-glance table of weights and water loads is below.
- Simple decision flow at the end of the next section helps decide if you should reinforce.
- Use a weight + load calculator if available to check your exact model and floor area.
Cast Iron Bathtub Weight by Type
Cast iron tubs are heavy because they’re made of iron coated with porcelain enamel. The enamel makes the tub easier to clean and protects against rust, but the iron is what drives the weight. Different styles and sizes shift how much your tub will weigh, how many gallons it can hold, and how that load spreads across the floor.
Alcove/built-in tubs
Most alcove cast iron tubs (the typical 30"×60" size) weigh around 320 lb empty. They often hold about 30–35 gallons to the overflow, which adds 250–290 lb when full. That means a standard tub + water total of about 570–610 lb, before counting the bather. Alcove models may be skirted or non-skirted; the skirt doesn’t change weight much, but framing and ledger support help spread the load into the surrounding walls.
Common questions come up here: How much does a 30×60 cast iron tub weigh? In most cases, a 30"×60" cast iron tub weighs about 300–350 lb, with ~320 lb a reliable average.
Freestanding & clawfoot
Freestanding cast iron tubs include clawfoot, slipper, and double-ended styles. They average ~385 lb, and larger models can reach 450–500 lb empty. These tubs often have higher waterlines, so even mid-size models can hold 60–80+ gallons, adding 500–670+ lb of water alone. Feet or a narrow base means the load is carried over smaller contact areas, which makes floor stiffness and subfloor quality more important.
Many ask: Are cast iron bathtubs heavy? Yes—tubs are very heavy. Even compact freestanding tubs weigh 250+ lb dry, and large ones can exceed 1,100 lb when filled with water and before anyone steps in.
Petite freestanding
Petite freestanding units can be a smart choice for small bathrooms or bathtub upstairs installs. These models commonly weigh ~250 lb empty and often hold similar water volumes to standard alcove tubs, depending on shape. They still feel solid, retain heat well, and reduce the stress on narrow hallways and stairs during delivery.
Visuals & tools
Table: Typical weights and loads by tub type
| Tub Type | Typical Size (L×W, in) | Empty Weight (lb) | Typical Capacity (gal) | Tub + Water (lb) |
| Alcove (standard) | 60×30 | ~320 | ~32 | ~587 |
| Freestanding/clawfoot | 60–75×30–34 | ~385 (up to 500) | 60–82 (max) | 885–1,183 |
| Petite freestanding | 45–55×26–30 | ~250 | ~30–35 | ~500–540 |
Notes:
- Water weight uses 8.34 lb/gal.
- Totals above exclude bathers.
- Exact weights vary by model, skirt/feet, wall thickness, and overflow height.
Quick decision flow:
Is the tub empty weight >400 lb or capacity >60 gal?
- Yes → Check joists, spans, and subfloor. Consider reinforcement.
- No → Continue.
Is the tub going on an upper floor or in an older home?
- Yes → Inspect joists and subfloor condition. Consider reinforcement.
- No → Continue.
Do you see any deflections, squeaks, or notched/drilled joists near the bath?
- Yes → Reinforce before install.
- No → Plan install with 3–4 helpers or lift gear. Proceed.
Total Loaded Weight: Tub + Water + Bather
The formula and examples
You only need one simple line:
Total loaded weight = tub weight + (gallons × 8.34 lb) + bather(s)
Standard alcove case:
320 lb tub + 32 gal × 8.34 lb ≈ 320 + 267 = 587 lb (add bather to get final total)
Large freestanding case:
500 lb tub + 82 gal × 8.34 lb ≈ 500 + 683 = 1,183 lb (add bather to get final total)
Real-life example of a person:
320 lb tub + 32 gal water (267 lb) + 180 lb bather ≈ 767 lb
If you’re wondering, How much does a 5 ft cast iron bathtub weigh? A 5-foot (60") cast iron tub typically weighs around 300–350 lb empty; ~320 lb is a good planning number for a standard alcove tub.
Weight distribution and psf (pounds per square foot)
Your floor is designed for a uniform live load, usually 40 psf in homes. A tub is a concentrated load over a relatively small footprint. The good news is that the load spreads out through the tub base, the subfloor, and then into joists and walls. The bad news is that weak subflooring, long joist spans, or small bearing areas (like clawfoot feet) can spike pressure in certain spots.
- Dead load is the weight of the tub itself, framing, tile, and subfloor. These are permanent.
- Live load is temporary—people and water in the tub, plus moveable items.
An alcove tub often spreads weight into side walls with a ledger and into the floor along its base. Freestanding tubs may need load spreaders (wide pads or plates under feet) when installed on tile or older pine floors to reduce point pressure.
How much does water add to a cast iron tub?
- 1 gallon ≈ 8.34 lb
- 32 gallons ≈ 267 lb
- 82 gallons ≈ 683 lb
In short, water adds more weight than the empty tub in many cases. That’s why capacity matters as much as the bare tub weight.
Can My Floor Support a Cast Iron Tub?
Residential code basics and common joist specs
Most U.S. homes use a 40 psf live load for residential floors by design. Bathrooms also carry a small dead load (often 10–20 psf) for tile, mortar, and fixtures. These are uniform design numbers, but a tub acts over a smaller area, so joist size, spacing, and span decide how stiff the floor feels and how well it resists deflection.
Why does uniform vs. point load matter? A 40 psf room rating does not mean you can drop a 1,000 lb point load on a corner without checking the structure. Tubs are long and heavy but mostly static. You want the weight to sit over multiple joists and spread through strong subflooring. That’s what keeps grout from cracking and floors from bouncing.
Step-by-step floor check
Use this quick inspection before you buy or install:
Find joist details:
Measure joist depth (e.g., 2×8, 2×10), spacing (e.g., 16" o.c.), and clear span between supports.
Check subfloor:
Note thickness (e.g., 5/8" vs. 3/4" plywood) and condition. Look for water damage near the old tub or toilet.
Scan for red flags:
- Deflection or bounce when you walk
- Squeaks, cracked grout, or soft spots
- Notched or drilled joists near plumbing
Decide on placement:
- Place the tub so weight crosses two or more joists, not just one.
- For clawfoot tubs, consider load spreaders or pads under each foot.
When in doubt, call a pro:
A licensed contractor or structural engineer can size reinforcement. It’s a short visit that removes guesswork.
Reinforcement options
- Sistering joists: Add full-length lumber alongside existing joists.
- Add blocking or a beam: Shortens spans and stiffens the floor.
- Upgrade subfloor: Add a new 3/4" plywood layer, properly glued and screwed.
- Use load spreaders: Wider plates under feet to reduce point pressure on tile or softwood planks.
- Relocate the tub: Move slightly to align over stronger framing or a bearing wall.
If you’re installing a large freestanding model upstairs or in an older home, talk to a structural pro first. A small reinforcement now is cheaper than fixing cracked tile and ceilings later.
Installation & Moving Logistics (Upstairs, Narrow Halls, Stairs)
Moving and installing a cast iron tub is a team sport. Even a petite unit is heavy and awkward through doorways, landings, and the top of the stairs. Smart planning prevents damage to floors, walls, and backs.
Delivery planning checklist
Measure:
Doorways, hallways, stair width, turns, and ceiling height on every level of the route.
Protect finishes:
Cover stairs, corners, and door jambs. Lay down ram board or plywood paths.
Plan the route:
Identify the widest path with the fewest tight turns. Remove doors or trim if needed.
Confirm rules:
Check permits or HOA rules for delivery hours or elevator use if in a condo.
Stage tools:
Have dollies, straps, and padding ready at entry, landing, and bathroom.
Labor, equipment, and safety
People:
Plan for 3–4 people. Even with a dolly, someone must steer and spot.
Equipment:
Piano dolly, moving straps, and stair-climbing dolly where possible.
Temporary ramps for steps and thresholds.
Technique:
Keep hands dry and wear grippy gloves. Lift with legs, not your back.
Avoid lifting over heads or twisting with load. Take breaks.
Real-world moving tips
Remove what you can:
On clawfoot tubs, remove the feet to clear tight corners. Keep hardware bagged and labeled.
Be careful with old tubs:
If you need to remove a cast iron tub during a remodel, cutting or breaking it is common. A sledgehammer can break old cast iron in place, but use full PPE and protect surroundings. Know that the broken pieces are still heavy.
Disposal:
Cast iron can be scrapped. Rates vary by region (often pennies per pound). Call local yards for pickup and price.
Some salvage yards or reuse centers accept vintage cast iron tubs in good shape.
Real-World Cases, Pro Insights, and Social Proof
Installers and homeowners agree on a few core points about cast iron tub weight:
- Upstairs bathrooms and older homes often need extra floor support. The risk is not just total weight—it’s also point loads at feet, long spans, and weak subfloors.
- Moving a cast iron tub is heavy even for pros. People report lifts in the 250–300+ lb range for small sections and full tubs closer to 300–500 lb. Teams of 3–4 are common for safe handling.
- Jobs go well when there’s prep, a clear path, and protection on stairs and floors. They go wrong when teams rush or underestimate how big and heavy the tub is.
If you’re restoring an 1880s or early 1900s home, you might find a vintage cast iron tub. These often weigh about the same as modern models of similar size because the enamel coating on cast iron and wall thickness are similar. The shape (like slipper profiles) affects capacity more than the age itself.
Cast Iron vs. Other Tub Materials (Weight, Cost, Performance)
If you find cast iron bathtubs too heavy, you can also choose an acrylic bathtub. Acrylic bathtubs are made by thermoforming acrylic sheets and are usually reinforced with fiberglass and resin. As a result, cast iron bathtubs are much heavier than acrylic ones.
Choosing between acrylic tub vs cast iron tub or enameled steel tubs comes down to weight, comfort, cost, and install complexity.
- Cast iron: Heaviest (240–500 lb empty). Very durable, quiet, and holds heat well. Can chip if hit hard and may rust at damaged spots if the porcelain is cracked. More expensive and harder to move. Often the most durable for long-term use.
- Acrylic: Light (60" tub often ~109 lb). Easy to handle on stairs, many shapes. Warm to the touch. Can scratch, but surface fixes are often easier. Not as stiff as iron; quality varies.
- Enameled steel: Mid-weight (150–200 lb). Hard surface, but tends to cool faster than acrylic or cast iron. Can chip to steel; rust may follow if not repaired.
When should you choose lighter materials? If the tub goes upstairs, the route is tight, your joists are long, or your budget cannot include reinforcement, lighter acrylic or enameled steel is a smart move. You still get a good soak, and your install team will thank you.
Ownership Factors: Budget, Maintenance, Recycling/Disposal
Total project costs
When you set your budget, look beyond the sticker price of the tub:
- Tub price: cast iron often $1,400–$9,000+ depending on size and finish
- Delivery and moving labor or equipment
- Reinforce the floor if needed (joists, blocking, subfloor)
- Plumbing and drain/overflow kit
- Tile, waterproofing, and finish materials
- Permits if required
It can be cheaper to reinforce before install than to fix cracked tile or ceilings after a problem.
Maintenance and Lifespan
A cast iron bathtub is among the most durable bathtub materials available, and can last decades with proper care. Cast iron tubs retain heat exceptionally well, making them ideal for long, relaxing baths. To maintain your freestanding cast iron or alcove cast iron tub, keep the enamel coating on cast iron clean and free from scratches or chips. Use gentle cleaners recommended for cast iron bathtubs—avoid harsh chemicals, steel wool, or abrasive pads that can damage the porcelain enamel. For clawfoot tubs or freestanding tubs, routinely check floor support, ensuring the heavy tub and its weight when filled with water do not cause shifting. Knowing how you clean a cast iron bathtub properly ensures the tub remains durable and visually appealing for decades. Compared with an acrylic bathtub or enameled steel tubs, cast iron tubs may require more care but reward homeowners with unmatched longevity and heat retention.
Disposal / Recycling
When it’s time to remodel or remove an old cast iron or alcove cast iron tub, remember that cast iron is recyclable. Because these tubs are extremely heavy—some freestanding cast iron tubs weigh up to 500 pounds—they can be sold for scrap at local recycling centers. Pickup may be available for a fee, depending on the weight of a cast iron tub and local market rates. Homeowners looking to remove a cast iron tub from a bathroom renovation should plan carefully; older clawfoot models or freestanding tubs may need to be lifted top of the stairs in sections, sometimes requiring a sledgehammer to split the old bathtub safely if space is tight. If the cast iron bathtub is still in good condition, consider resale, donation, or repurposing rather than scrapping, keeping it out of the landfill. Proper planning also helps protect flooring and ensures floor support can handle the tub weight, whether in upstairs bathrooms or older homes.
FAQs
1. Will my floor support a cast iron tub?
Many floors can support a standard cast iron tub, but it depends heavily on joist size, spacing, span, and subfloor quality. Since cast iron bathtubs are extremely heavy and may weigh 385 pounds or more empty—and up to 1,000 pounds filled with water—it’s important to evaluate weight limits before installing. Installing a cast iron bathtub upstairs or on older flooring often requires a structural check, as the amount of weight concentrates on a small footprint, unlike lighter steel bathtubs or acrylic tubs. Look for floor deflection, squeaks, or damage as warning signs, and consider reinforcing joists or adding blocking to safely support the tub weight, especially for freestanding or clawfoot bathtubs. Proper planning ensures your floor can handle the heavy load of the tub, water, and bather without risk of damage. Prudent reviews suggest consulting a contractor if unsure.
2. Are cast iron bathtubs heavy?
Yes. Cast iron tubs are among the heaviest bathtub materials, with empty tubs typically ranging from 240–500 pounds. Some freestanding cast iron tubs, including large clawfoot bathtubs, weigh 385 pounds or more before adding water. Once filled, the amount of weight can exceed 1,000 pounds, depending on the size of the tub and gallons of water it holds. This is far heavier than a typical steel bathtub or acrylic bathtub, which makes installing a cast iron bathtub more labor-intensive and sometimes requires multiple people or lifting equipment. Since cast iron bathtubs are coated with enamel, they retain heat exceptionally well and offer long-term durability, but their weight limits must be respected to prevent floor damage. Prudent reviews note that careful planning for delivery and placement is essential to avoid injuries or property damage.
3. What are the disadvantages of cast iron bathtubs?
The main drawbacks of cast iron bathtubs relate to weight, cost, and installation complexity. These tubs are heavy and may exceed 500 pounds when filled with water, which can necessitate floor reinforcement, especially for upstairs bathrooms or older homes. Unlike acrylic or steel bathtubs, the shapes of cast iron tubs are more limited, though clawfoot bathtubs remain popular for aesthetics. The enamel coating on cast iron can chip or rust if damaged, requiring repair or refinishing. Moving an old cast iron tub is challenging; sometimes the tub must be cut in half with a sledgehammer or other tools. While the durability is excellent, the amount of weight and complexity of installing a cast iron bathtub make it less convenient than lighter options. Prudent reviews emphasize checking weight limits and planning floor support to avoid costly damage.
4. Which is better, acrylic or cast iron?
Choosing between an acrylic bathtub and a cast iron tub depends on priorities. Cast iron tubs excel in durability, heat retention, and quiet soaks. They are coated with enamel, which protects the surface and adds longevity, and standard cast iron or freestanding cast iron tubs are highly regarded in prudent reviews for long-term use. However, they are extremely heavy, often weigh 385 pounds or more, and the total amount of weight when filled with water may exceed 1,000 pounds, so floor support and weight limits must be considered. In contrast, acrylic bathtubs are lightweight, easier to install, and often more flexible in design. If the right tub for your bathroom must include upstairs placement or a tight route, acrylic is more practical. For homeowners prioritizing durability and heat retention, cast iron tubs outdoors or indoors remain a premium choice.
5. What do you use to clean a cast iron bathtub?
Cast iron bathtubs, which are coated with enamel, are relatively easy to clean when properly maintained. For daily cleaning, use mild dish soap, warm water, and a soft sponge to avoid damaging the enamel surface. For stubborn soap scum, a baking soda paste works well. Avoid harsh abrasives or steel wool that can chip the enamel and compromise the tub’s durability. How do you clean a cast iron bathtub correctly is essential, especially for freestanding cast iron tubs, clawfoot bathtubs, or standard cast iron tubs that may weigh 385 pounds empty. Proper cleaning helps preserve heat retention, prevent rust, and maintain aesthetic appeal. Prudent reviews note that since cast iron bathtubs are heavy and may be difficult to move, consistent cleaning avoids costly refinishing. Comparatively, acrylic bathtubs require gentler care but are lighter and easier to manage.
6. Can you use a Magic Eraser on a cast iron tub?
Yes, with care. Magic Erasers are micro-abrasive and can dull the enamel coating on cast iron, so it’s recommended to test a small area first and use light pressure. Avoid using it on chipped or rusted areas to prevent further damage. Since cast iron bathtubs are heavy and may already require careful handling during installing a cast iron bathtub, cleaning tools should minimize risk to the surface. For freestanding cast iron tubs, clawfoot bathtubs, or any standard cast iron tub, regular gentle cleaning preserves the amount of weight the tub can safely support over time, maintains heat retention, and keeps the surface smooth and shiny. Prudent reviews suggest combining Magic Erasers with mild soap for spot cleaning while protecting the enamel finish.
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