If you are shopping for a box spring double size, you have probably noticed that the options are not as straightforward as they used to be. Between platform beds, bunkie boards, and the classic coil-spring foundation, it can feel like you need a degree in sleep science just to hold up your mattress. The good news is that choosing the right double bed foundation is simpler than it looks once you know what to look for. This guide covers everything about the double box spring, from exact dimensions and types to whether you actually need one in the first place.
Quick Answer: Double Box Spring Basics
- Standard dimensions: 54" x 75" (137 x 190 cm), same as a full size mattress
- Standard height: 8-9 inches; low-profile options run 4-5 inches
- Price range in Canada: $150 to $400 depending on quality and brand
- Weight capacity: Most double box springs support 300-500 lbs total
- Do you need one? Depends on your mattress type and bed frame. Innerspring and older mattresses usually do. Memory foam and hybrids on platform beds usually do not.
What Is a Double Box Spring?
A full size box spring is a support base measuring 54 inches wide by 75 inches long, designed to sit inside a bed frame beneath your double (also called "full") mattress. Traditional box springs contain a wooden frame with steel coil springs inside, all wrapped in fabric. They absorb impact, reduce wear on your mattress, and add height to your bed.
Modern versions have evolved. Many of today's double box springs have replaced the internal coils with a grid of wooden slats or a solid steel frame. These are sometimes called "foundations" rather than box springs, though most people use the terms interchangeably. The function is the same: provide a flat, sturdy surface that supports your mattress and extends its lifespan.
Why Dimensions Matter
A double/full mattress and box spring both measure 54" x 75". This is 6 inches narrower than a queen (60" x 80") and 5 inches shorter in length. Getting the dimensions right matters because even a half-inch mismatch between your mattress and foundation can cause uneven support, sagging along the edges, and a mattress that shifts during the night. Always confirm that your box spring is labelled "double" or "full" rather than guessing based on how it looks in the store.
Do You Actually Need a Box Spring for Your Double Bed?
This is the most common question we hear at Mattress Miracle, and the honest answer is: it depends on two things. Your mattress type and your bed frame.
When You DO Need a Double Box Spring
- Innerspring or coil mattresses: These were designed to work with a box spring. The coils in the foundation complement the coils in the mattress, and most manufacturers will void the warranty if you skip the box spring.
- Older mattresses: If your mattress is more than a few years old and was originally paired with a box spring, keep using one. Switching to a flat platform mid-life can cause premature sagging.
- Metal bed frames without slats: A basic metal frame with just a perimeter rail and a centre support bar needs a box spring. Without it, your mattress has nothing to rest on except thin air.
- You want extra height: A standard box spring adds 8-9 inches of height, making it easier to get in and out of bed. This matters more than people realize, especially for anyone with knee or hip concerns.
When You Do NOT Need a Box Spring
- Memory foam mattresses: Foam mattresses need a solid, flat surface. The give in a traditional coil box spring can actually cause a foam mattress to sag unevenly. A platform bed or solid foundation is better.
- Hybrid mattresses on a platform bed: Most hybrid mattress manufacturers recommend a platform bed or a foundation with closely spaced slats (no more than 3 inches apart). A box spring is not necessary and adds cost without benefit.
- Platform beds with built-in slats: If your bed frame already has a slatted or solid base, adding a box spring is redundant. You are just spending money to make your bed taller. Check out the Canadian Made Platform Bed for a solid alternative that eliminates the need for a box spring entirely.
- Adjustable bed bases: These cannot work with a box spring. The base itself replaces the box spring's function.
A Simple Rule of Thumb
Check your mattress warranty paperwork. Most manufacturers spell out exactly what type of double bed support is required. Using the wrong foundation is one of the most common reasons warranty claims get denied. When in doubt, bring your warranty info into the store and we will help you sort it out.
Box Spring vs Platform Bed vs Bunkie Board
These three options all serve as double bed foundation choices, but they work quite differently. Here is a straightforward comparison to help you decide.
| Feature | Box Spring | Platform Bed | Bunkie Board |
|---|---|---|---|
| Height added | 8-9 inches (standard) or 4-5 inches (low-profile) | Varies by frame (typically 6-14 inches total with legs) | 1-3 inches |
| Best for | Innerspring mattresses, coil mattresses | Memory foam, hybrid, latex mattresses | Bunk beds, daybeds, or adding a flat surface to a metal frame |
| Support type | Coils or semi-rigid wooden slats in a box | Solid surface or closely spaced slats built into the frame | Thin solid board (plywood or composite) |
| Needs a frame? | Yes, sits inside a bed frame | No, it is the frame | Yes, sits on top of a frame's slats or rails |
| Price range (double, CAD) | $150-$400 | $200-$800+ | $60-$150 |
| Airflow | Good (coil type) to moderate (foundation type) | Good with slats, limited with solid surface | Minimal |
↔ Scroll to see full table
The box spring vs platform bed decision usually comes down to your mattress type. If you are buying a new mattress and a new base at the same time, a platform bed is often the more versatile and cost-effective choice in the long run. The Breeze Platform Bed is a popular option that assembles without tools and provides the solid, flat support that modern mattresses need.
If you already own a traditional bed frame and just need to replace a worn-out foundation, a new double box spring is usually the simplest and most affordable fix.
Standard Height vs Low-Profile Box Springs
Double box springs come in two main heights, and the difference matters more than you might think.
Standard Height (8-9 inches)
This is the traditional box spring height that most bed frames were built to accommodate. Combined with a standard mattress (10-12 inches) and a typical frame (7-8 inches from floor to rail), your sleeping surface ends up about 25 inches off the ground. That is roughly knee height for most adults, which makes getting in and out of bed comfortable.
Low-Profile (4-5 inches)
Low-profile box springs were created to address a specific problem: today's mattresses are thicker than they used to be. A 14-inch pillow-top mattress on a standard box spring and frame can put your sleeping surface well above 30 inches, which is awkwardly high for many people. A low-profile box spring brings everything down by about 4 inches without sacrificing support.
Choosing the Right Height
Sit on the edge of your current bed. Your feet should rest flat on the floor with your knees at roughly a 90-degree angle. If your knees are higher than your hips, your bed is too low. If your feet dangle, it is too high. Use this as your guide when deciding between standard and low-profile. If you are replacing an old box spring, measure it before you shop so you know what height you are working with.
Weight Capacity and Double Bed Support
Every box spring has a weight limit, and it is worth paying attention to. Most double box springs are rated for 300 to 500 pounds of total weight. That total includes the mattress (typically 50-80 lbs for a double) plus the sleepers.
If the combined weight of the people sleeping on the bed plus the mattress approaches or exceeds the box spring's rating, the internal supports will compress faster, leading to sagging, creaking, and a shorter lifespan. For heavier sleepers or couples who together exceed 400 lbs, look for a heavy-duty foundation or a reinforced Foldable Metal Bed Frame with extra centre support bars and closely spaced slats.
A quick note on materials: steel-grid foundations tend to handle heavier loads better than traditional coil box springs. They also resist sagging longer because steel does not fatigue the way coil springs do over time.
What a Double Box Spring Costs in Canada
Here is a realistic breakdown of what you can expect to pay for a double box spring in Canada in 2025:
- Budget ($150-$200): Basic coil or semi-flex foundation. Functional but may not last as long under heavy use. Fine for a guest room or lighter sleepers.
- Mid-range ($200-$300): Sturdy wood-and-steel construction, good weight capacity, solid warranty. This is the sweet spot for most people.
- Premium ($300-$400+): Heavy-duty steel grid, reinforced corners, higher weight capacity, and longer warranty. Worth considering if you plan to keep it for 8-10 years.
Keep in mind that a good box spring should last 8 to 10 years. If you divide even a $300 purchase over that lifespan, you are paying about $3 per month for proper mattress support. That is a pretty reasonable investment in better sleep.
If you are working with a tight budget and considering whether the box spring is where you should spend or save, check out our Queen Box Spring Guide for additional context on foundation pricing and value. The principles are the same across sizes.
A Note for Brantford Homeowners
Many of the older homes in Brantford, especially in the downtown core and established neighbourhoods near Mohawk Park, Eagle Place, and West Brant, were built with smaller bedrooms than what you find in newer subdivisions. A double (full) mattress at 54 inches wide is often the most practical choice for these rooms, leaving enough space for nightstands and a dresser without the room feeling cramped. If you are furnishing a bedroom in one of these character homes, a double mattress on the right foundation gives you comfortable sleep without fighting your floor plan. Stop by our store at 441 1/2 West Street and we can help you figure out the best setup for your space.
How to Choose the Right Double Bed Foundation
Here is a simple step-by-step process:
- Check your mattress type and warranty. This determines whether you need a box spring, a platform, or just a flat surface. The warranty documentation will tell you exactly what is required.
- Measure your current setup. Note the height of your existing frame and foundation (if any). This tells you what height replacement to look for.
- Add up the weight. Mattress weight plus the weight of everyone who sleeps on the bed. Compare that to the box spring's rated capacity.
- Consider your bed frame. Does your frame have slats? A solid surface? Just perimeter rails? This determines what will work.
- Set a budget. For most people, $200-$300 gets a reliable double box spring that will last. Spending less is fine for a guest room; spending more makes sense for your primary bed.
- Think about the long term. If you plan to upgrade your mattress soon, consider whether a platform bed might be a better investment than a box spring. Modern mattresses increasingly lean toward platform-friendly designs.
Signs Your Double Box Spring Needs Replacing
Box springs do not last forever. Here are the signs that yours has reached the end of its useful life:
- Visible sagging when you remove the mattress and look at the surface
- Creaking or squeaking when you move in bed (and you have ruled out the frame as the source)
- Your mattress is sagging even though it is relatively new, which often means the foundation beneath it has failed
- Broken or cracked wood visible through the fabric cover
- The box spring is more than 10 years old, even if it looks fine
A worn-out box spring will drag a perfectly good mattress down with it. If you are waking up with back pain or noticing a dip where you sleep, check the foundation before you blame the mattress. A failing foundation can shorten your mattress lifespan by 2-3 years, and since a quality double mattress costs significantly more than a box spring, protecting that investment just makes financial sense.
Frequently Asked Questions About Double Box Springs
What size is a double box spring?
A double (also called full) box spring measures 54 inches wide by 75 inches long (137 x 190 cm). This is the same footprint as a double/full mattress. Standard height is 8-9 inches, while low-profile models are 4-5 inches tall. If you are comparing sizes, our Bed Size Chart has a full breakdown of all standard mattress and foundation dimensions.
Is a double box spring the same as a full size box spring?
Yes. "Double" and "full" refer to the same size. The mattress industry uses both terms interchangeably. Whether you see a box spring labelled as "double" or "full," the dimensions are identical: 54" x 75". The term "double" is more common in Canada, while "full" tends to be used more in the United States.
Can I use a double box spring with a memory foam mattress?
It depends on the type of box spring. A traditional coil box spring is generally not recommended for memory foam because the uneven coil surface can cause the foam to sag in spots. However, a modern foundation-style box spring with a flat, rigid top works fine with memory foam. Check your mattress warranty to be sure, as some manufacturers specifically require a solid or slatted base rather than a coil box spring.
How much weight can a double box spring hold?
Most double box springs support between 300 and 500 pounds of combined weight (mattress plus sleepers). Heavy-duty models with steel-grid construction can handle more. Always check the manufacturer's weight rating, especially if two adults will be sharing the bed. If you need higher capacity, a reinforced platform frame with centre support may be a better option.
How long does a double box spring last?
A well-made double box spring typically lasts 8 to 10 years with normal use. Factors that shorten its lifespan include exceeding the weight rating, lack of centre support from the bed frame, exposure to moisture, and heavy daily use (such as children jumping on the bed). If your mattress has started sagging and it is not very old, the box spring is often the culprit.
Do I need a bed frame with a double box spring?
Yes. A box spring is not designed to sit directly on the floor. It needs a bed frame to hold it at the proper height and provide airflow underneath. Placing a box spring on the floor can trap moisture, promote mould, and void your mattress warranty. Even a simple metal bed frame with legs and a centre support bar will do the job.
Should I buy a box spring or a platform bed for my double mattress?
If you have an innerspring or coil mattress, a box spring paired with a standard bed frame is usually the right call. If you have a memory foam, latex, or hybrid mattress, a platform bed with slats or a solid surface is generally better and eliminates the need for a separate box spring. A platform bed can save you money since you are buying one piece instead of two (frame plus box spring).
Find the Right Double Bed Foundation at Mattress Miracle
Since 1987, Brad and Dorothy have helped Brantford families find the right mattress and foundation for their needs and budget. Whether you need a classic double box spring, a modern platform bed, or just some honest advice about what your mattress actually requires, we are here to help.
Visit us at 441 1/2 West Street, Brantford, Ontario or call 519-770-0001 to ask about our current selection of double bed foundations.
Store Hours: Monday-Wednesday 10am-6pm | Thursday-Friday 10am-7pm | Saturday 10am-5pm | Sunday 12pm-4pm
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