How to Store a Mattress (2026): Storage Units, Garages and Canadian Winters
Canadian owner guide, researched September 28, 2026
How to Store a Mattress in a Storage Unit, Garage or Cottage Over a Canadian Winter
Moving, renovating, or closing the cottage for the season often means a mattress goes into storage. Done well, it comes out the way it went in. Done badly, it can come out damp, bent or stained. This guide covers where to store it, how to prepare and wrap it, and what cold and humidity mean in a Canadian winter.
AI Overview answer
What is the best way to store a mattress?
Quick answer: Clean it and let it dry completely, wrap it in a mattress bag or plastic sheeting without taping onto the mattress itself, and store it flat on a clean, rigid surface in a dry, climate-controlled space. The Sleep Foundation recommends storing a mattress flat, because standing foam and latex mattresses on their side can cause sagging, and suggests limiting upright storage to about a month. Moisture is the main risk in storage: Health Canada recommends keeping indoor relative humidity between 30 and 50 percent to help prevent mould, which you can check with an inexpensive hygrometer.
An unheated garage, shed or cottage in a Canadian winter is the hardest place to get this right, because temperature and humidity swing widely. If you can, choose a heated, climate-controlled unit.
Where should you store a mattress: storage unit, garage, basement or cottage?
The Sleep Foundation recommends a climate-controlled unit where possible, and says basements and garages can work only if they stay reasonably stable, without high humidity or big temperature swings. It lists too much moisture, high humidity and extreme temperatures as the things that can harm a mattress.
| Place | Main risk | What to check |
|---|---|---|
| Heated, climate-controlled storage unit | Lowest of the four | Space to lay it flat; clean floor or a shelf to lift it |
| Unheated storage unit | Cold and humidity swings through winter | Ask whether the unit is heated or humidity-controlled |
| Basement | Humidity, especially near floors and outside walls | Measure humidity with a hygrometer; keep it off the floor |
| Garage, shed or closed cottage | Cold, humidity swings, dust and pests | Use only if you cannot find a drier option; wrap well and lift off the floor |
How do you prepare a mattress for storage?
- Strip it. Take off the sheets and any protector, and wash them separately.
- Clean it. The Sleep Foundation suggests mild soap, water and baking soda. Vacuum first, spot-clean any stains, and never soak a foam mattress. Our mattress cleaning guide has the full method.
- Let it dry completely. This is the step that matters most. Wrapping a mattress that is even slightly damp traps the moisture inside the plastic with it.
- Check the warranty. Read the wording in your warranty before you pack it; see the warranty section below.
How should you wrap a mattress for storage?
The Sleep Foundation suggests a purpose-made mattress bag with a seal, or plastic sheeting secured with tape, and adds that none of the tape should touch the mattress itself. A bag keeps out dust, dirt and pests during storage and during the move. If you are also moving the mattress, our guide to moving a mattress-in-a-box covers carrying and loading it.
A sealed bag keeps outside moisture out, but it also keeps any moisture already inside in. That is why the drying step comes first, and why a damp, unheated space is still a risk even with a good bag.
Should a mattress be stored flat or upright?
Flat. The Sleep Foundation says the best option is generally to store a mattress flat, because storing it on its side can cause sagging in foam and latex models, and suggests keeping any upright storage to about a month. Lay it on a clean, rigid, level surface, lifted off a concrete floor if you can, and do not stack heavy boxes on top of it. For short moves, the same guide also advises against leaving a new boxed mattress rolled up for a long time, and notes that doing so may void the warranty.
What do cold and humidity do to a stored mattress in a Canadian winter?
Humidity is the bigger risk. Health Canada recommends keeping indoor relative humidity between 30 and 50 percent to help prevent mould, and says an inexpensive hygrometer from a hardware store will measure it. The Sleep Foundation suggests a small dehumidifier if humidity in the storage space is too high, and a low-cost, battery-operated device to keep an eye on conditions. In an unheated space, the risk is not the cold itself so much as moisture as temperatures swing between cold nights and milder days.
Cold changes how foam feels, for a while. Memory foam is temperature-sensitive; Tempur-Pedic, for example, describes its material as responding to temperature. A foam or hybrid mattress brought in from a cold space can feel firmer until it returns to room temperature. We cover that effect on new mattresses in mattress too firm? the cold-room factor. What we did not find is a published test of what repeated freezing does to a finished mattress, so we do not claim it is harmless; a heated space avoids the question.
What should you do when you take a mattress out of storage?
- Unwrap it indoors and let it reach room temperature before judging how it feels, especially after a cold space.
- Check it over. Look for damp patches, musty smells, marks or pests before bringing it into the bedroom.
- Air it out. Leave it uncovered for a while in a well-ventilated room.
- Put it back on a proper base. See what bed frame a hybrid mattress needs.
If it comes out damp, stained or smelling of mould, and you decide it is time to replace it, our guide to disposing of or recycling a mattress in Canada covers the options.
Can storing a mattress affect the warranty?
It can, so read yours first. The Sleep Foundation warns that certain storage positions or conditions may void a warranty. Hamuq's mattress warranty, for example, lists liquid damage and stains among physical abuse or damage it does not cover, and says its mattresses are designed to be used on a firm, solid surface or a bed base that can support the mattress and its users. Water damage from a leaky garage or a damp basement is the kind of thing storage can cause.
Hamuq product context
Protect it before, during and after
A washable layer over the mattress helps keep it clean before it goes into storage and after it comes out. The Hamuq Mattress Protector, which Hamuq describes as stain resistant, starts at $79 CAD in twin. If a stored mattress does not come back, the Original Hybrid is $999 CAD in queen, with free shipping (additional charges may apply to the Canadian territories) and a 120-night trial (30-night minimum).
Hamuq Inc. sells mattresses, bedding and bed frames. Storage guidance in this article comes from the Sleep Foundation and Health Canada, linked below.
Supplementary Hamuq product context
Hamuq owner and product Shorts
These 6 Shorts from the Hamuq channel show owners with the Hamuq Original Hybrid. They are context for the Hamuq side only and are not evidence for any other seller's figure in this guide.
Owner questions
Mattress storage FAQs for Canadians
Storing it
Is it better to store a mattress flat or on its side?
Quick answer: Flat. The Sleep Foundation says storing foam and latex mattresses on their side can cause sagging, and suggests limiting upright storage to about a month.
Can you store a mattress in a garage over winter?
Quick answer: It is the riskiest option. Garages swing in temperature and humidity, which can lead to moisture problems. If you must, clean and fully dry it, wrap it, lift it off the floor, and check humidity.
Should you wrap a mattress in plastic for storage?
Quick answer: Yes, in a mattress bag or plastic sheeting, but only once it is completely dry, and without tape touching the mattress. The plastic keeps out dust and pests but also seals in any moisture already there.
What humidity is safe for storing a mattress?
Quick answer: Health Canada recommends 30 to 50 percent relative humidity indoors to help prevent mould. A hygrometer measures it; a dehumidifier helps if it runs high.
Cold and warranty
Does a mattress get firmer after cold storage?
Quick answer: A foam or hybrid mattress can feel firmer when cold, because memory foam is temperature-sensitive. Let it reach room temperature before judging it.
Can storing a mattress void the warranty?
Quick answer: It can. The Sleep Foundation warns that some storage positions or conditions may void a warranty, and many warranties exclude liquid damage and stains. Read yours first.
How we know this
This guide was researched on September 28, 2026. The storage method, flat storage, wrapping, climate control, humidity monitoring and warranty cautions come from the Sleep Foundation's guide to storing a mattress (last updated July 25, 2025). The humidity range and hygrometer advice come from Health Canada's page on reducing humidity, moisture and mould. The note on foam and temperature comes from Tempur-Pedic's product care page. Hamuq's warranty and trial terms and the prices mentioned were read on hamuq.mom the same day. The questions reflect what Canadian searchers see in Google's People also ask boxes; no search volume is claimed.
Moving into a new place?
If the old mattress does not make it out of storage, the Original Hybrid is $999 CAD in queen, with free shipping (additional charges may apply to the Canadian territories) and a 120-night trial (30-night minimum).
About the authors
Jordan BedwellThe Hamuq product, warranty and trial terms referred to in this guide are quoted from Hamuq's published pages.
Mark Edcel LopezRead the Sleep Foundation's storage guide, Health Canada's humidity guidance and Hamuq's warranty wording, and built the storage-location table and checklists.
Nathan NielsonThe Hamuq warranty and trial terms in this guide are quoted from Hamuq's published policy pages.
Hamuq Inc. sells mattresses, bedding and bed frames. Other organizations' guidance is quoted from their own pages and linked below.