Understanding Mattress-in-a-Box Expansion
When you unbox your new mattress in a box, it can seem almost magical how a full-sized bed emerges from such compact packaging. Vacuum-sealing technology compresses the mattress for easy shipping, and once unwrapped, it begins to expand back to its intended shape.
Most mattresses, like the Sleep Republic hybrid mattress, start expanding immediately. However, full expansion can take anywhere from a few hours to 72 hours, depending on the materials, room temperature, and airflow.
Explore our hybrid mattress collection →
Why Expansion Time Varies
1. Material Composition
Hybrid and memory foam mattresses expand differently.
-
Hybrid mattresses (like the Sleep Republic Mattress) contain both pocket springs and foam layers, which regain their shape faster — often within 4 to 6 hours.
-
All-foam mattresses may take longer (up to 72 hours) because dense foam layers need more time to decompress fully.
2. Room Environment
Warm, well-ventilated rooms encourage faster expansion. In cooler climates or air-conditioned rooms, the process may slow down — something to keep in mind for Melbourne’s winter nights.
3. Packaging Duration
The longer a mattress stays compressed in its box, the more time it may need to reach full size. Thankfully, Sleep Republic mattresses are delivered quickly across Australia, ensuring minimal compression time and optimal freshness on arrival.
When Is It Safe to Sleep on Your New Mattress?
Technically, you can sleep on your Sleep Republic mattress a few hours after unboxing. However, allowing a little extra time helps it reach its full comfort and support potential.
Our hybrid models — including the Sleep Republic Luxe Mattress — feature high-definition pocket springs and gel-infused memory foam, designed to offer stable support even during early expansion. Still, waiting 6–8 hours ensures the best feel from the first night.
If you’d prefer to protect your new bed immediately, pair it with a Sleep Republic Mattress Protector to keep it fresh from night one.
Signs Your Mattress Has Fully Expanded
You’ll know your mattress is fully expanded when:
-
The surface feels even and supportive across the entire bed.
-
Corners and edges have regained their full height and shape.
-
The “new mattress smell” (from natural foam off-gassing) has mostly dissipated.
-
Lying on it feels balanced — not overly soft or uneven.
A Sleep Republic mattress typically reaches 100% expansion within 24 hours, thanks to its high-quality materials and hybrid pocket spring structure designed for rapid recovery.
Tips to Help Your Mattress Expand Faster
-
Unbox immediately after delivery.
The sooner you release it, the quicker it returns to shape. -
Let it breathe.
Keep the room ventilated with windows open or a fan running. -
Avoid heavy use early on.
Wait until it feels evenly expanded before placing heavy bedding or jumping in. -
Use a proper bed base.
A sturdy, supportive Sleep Republic bed base helps the mattress settle evenly and maintain long-term durability.
Why Sleep Republic Mattresses Expand Faster
Sleep Republic’s premium hybrid technology combines pocket springs, gel-infused memory foam, and natural latex, all engineered to regain form efficiently. Each layer is crafted for balance — contouring support, airflow, and pressure relief — meaning you’ll enjoy comfort without waiting days for the mattress to “fluff up”.
With a 150-night sleep trial, fast delivery, and a 12-year warranty, you can trust your Sleep Republic mattress to perform at its best from the moment it arrives.
Conclusion
Your mattress in a box doesn’t need to take days before it feels amazing. With Sleep Republic’s hybrid design, most customers experience full comfort within hours of unboxing — a testament to quality engineering and premium materials.
Whether you’re in Melbourne or anywhere across Australia, your best night’s sleep is just one unboxing away.
Shop the full Sleep Republic range →
FAQs
Can I sleep on my mattress before it’s fully expanded?
Yes, most hybrid mattresses are safe to sleep on after 4–6 hours. For full comfort and support, it’s best to wait 24 hours.
What happens if my mattress doesn’t fully expand?
If corners or edges remain compressed after 72 hours, contact Sleep Republic’s customer service — our team will guide you through solutions or replacements.
Does temperature affect mattress expansion?
Yes. Warm rooms help foam layers expand faster, while cooler temperatures can slow the process.
How long does the “new mattress smell” last?
Off-gassing typically fades within a few hours to a day, especially if the room is well-ventilated.
