At Bunk Beds Canada, we offer a good selection of bunk bed mattresses to go with our bunk beds, loft beds, or platform bed frames. 
Generally speaking, you can not use any mattress for bunk beds since the thickness of mattresses are not standard. What is standard is the length and width of the mattress. 
Mattress manufacturers’s main objective is to offer maximum comfort for each budget segment. In the bunk bed’s world, safety comes first, then comfort.

Safety Clearance

For the upper deck of your bunk bed as well as your loft bed, you need to consider safety clearance. That is, the distance from top of your mattress to the top of your guardrail. Thicker the mattress, less clearance you have and therefore more chance of accidents. 
Suggestions are to have 5” of clearance from top of your mattress to top of the guardrail. We believe to have more clearance for younger kids, at least 6”.

Aim for at least 6” of space from top of your mattress to top of the guard rail.

Mattress Thickness For Upper Bunk and Loft

For upper bunk and loft beds, we recommend a SIX inches thick mattress. This thickness works for all of our product lines. Some bunk beds design allow you to use a thicker mattress, that depends on the design. Our Cottage Collection, for example, you can get away with maximum 8” thick mattress for upper bunk.

Mattress Thickness For Lower Bunk

For the lower deck of your bunk bed, you no longer need to worry about safety, that is for the upper deck. For lower deck, you need to consider the comfort zone.

Comfort zone is the space you have between your mattress and bottom of the slats of the upper deck. Naturally, the less space there the more claustrophobic you feel.

We recommend to use a SIX inches thick mattress for the lower deck of your bunk bed for most of our bunk beds and EIGHT inches for single over double bunks and tall bunk beds.

Mattress Thickness For Platform Beds

For platform beds, you can use any thickness mattress as you please. Most mattresses are between 8 to 12” in the marketplace.