Bunk bed or loft bed
The one build where getting it exactly right genuinely matters. Slow, methodical, and double-check everything.
Not what you bought? Try Mattress in a box · Metal platform bed frame · Toddler bed and bed rail
What you need
In the box already: Allen key · Long bunk bolts, washers and barrel nuts · Guard rails · Ladder · Slats and clips · Anti-tip hardware
Before you open anything
- Measure your ceiling height. You need the mattress plus enough headroom for a child to sit up on the top bunk, usually around thirty inches above the mattress.
- Build it in the final position, in the room, with the door shut behind you. It will not move afterwards.
- Count every single bolt against the manual before starting. On a bunk bed, a missing bolt is a safety issue rather than an inconvenience.
- Allow real time. This is a two to three hour job and rushing it is exactly the wrong instinct.
Please don't skip these
- Top bunks are not for children under six. That is the standard guidance from safety regulators, not a suggestion.
- Guard rails on both sides of the top bunk, even the wall side. Children roll into the gap between bed and wall.
- The gap between the guard rail and the mattress top must be small enough that a child cannot slip through. Use the mattress thickness the manual specifies — a thicker mattress raises the sleeping surface and defeats the rail.
- Never let anyone sleep in it until every bolt has been checked twice and the bed has been anchored.
- No hanging anything from the bed: ropes, belts, scarves. That is a strangulation risk in a child's bed.
The whole thing, step by step
10 steps-
Count every bolt and part against the manual
Lay out all four posts, both bed frames, the rails, the ladder, the guard rails, and every bag of hardware. Count them against the list. Twice.
- All panels and posts laid out and labelled
- Count bolts, washers and barrel nuts against the manual
- Set anything missing aside and request it before you start
Watch out. On a bunk bed, do not substitute a bolt from the hardware store because it 'looks the same'. Bolt grade and length are engineered here. Request the real part. -
Build the bottom bunk frame first
Assemble the lower bed's side rails to the posts, finger-tight, so you have a rectangle standing on its four posts.
- Side rails to the posts, bolts and washers started
- Head and foot panels in
- Everything loose, nothing tightened yet
Tip. The posts are usually identical but the rails are not. Check head rail against foot rail for different hole patterns. -
Add the upper bunk rails, loose
With one person steadying each end, bolt the upper side rails and end panels onto the same posts. Still finger-tight. The frame will feel alarming at this stage and that is normal.
- One person per end, holding the posts vertical
- Upper rails bolted on finger-tight
- Washers under every bolt head
Watch out. Do not let go of the frame while bolts are loose. A half-bolted bunk frame will fold. -
Square and plumb it, then tighten hard
Check both diagonals on each bunk and check the posts are vertical with a level. Then tighten every bolt firmly with a wrench, not just the Allen key.
- Diagonals equal on the lower and upper frames
- Level against each post, both directions
- Tighten every bolt firmly with a wrench, then a full second lap
Tip. Firm means firm here. These bolts carry a child and the load changes every time someone climbs. Two full laps minimum. -
Fit all the slats and secure every one
Both bunks get their full set of slats, evenly spaced, and every slat screwed or clipped down. On a bunk bed no slat is optional.
- Count the slats against the manual, both bunks
- Even spacing, no gaps larger than the manual allows
- Screw or clip every slat, not just the end ones
Watch out. An unsecured slat on a top bunk can be pushed out from below by a child's feet. Secure all of them. -
Fit the guard rails on both sides
Bolt the guard rails to the top bunk on both sides, including the wall side. Tighten them fully and then try to move them.
- Both sides, even against a wall
- Bolts fully tightened with the wrench
- Pull hard on each rail to test it
Tip. If the kit only supplies one rail, order a second from the manufacturer. The wall-side gap is a recognized entrapment risk.Watch out. Measure the gap from the top of the mattress to the top of the rail. The manual gives a minimum — usually around five inches. A mattress thicker than specified raises the surface and shrinks that gap to nothing. -
Attach the ladder and test it with your own weight
Bolt or hook the ladder on according to the manual, tighten it fully, then climb it yourself. An adult's weight is the test, not a child's.
- Ladder brackets bolted, fully tight
- Check it cannot lift off its hooks
- Climb it yourself, all the way up, and bounce
Watch out. A ladder that merely hooks on must also have its securing screw or clip fitted. Unsecured ladders lift off under a climbing child's weight. -
Anchor the bed to the wall
Loft beds and tall bunks must be anchored. Find a stud, bracket the frame to the wall, and tighten it so the bed cannot rock away from the wall.
- Stud finder, or a heavy-duty anchor rated well above the bed's weight
- Bracket to the post and to the wall
- Push the frame hard to confirm it does not move
Tip. Even if the manual calls anchoring optional, do it. A loft bed is tall, narrow, and gets climbed.Watch out. A loft bed with a desk underneath is the tallest, narrowest furniture in the house. Anchor it. -
Check the mattress thickness against the rail
Put the top mattress in and measure from its surface to the top of the guard rail. If it is less than the manual's minimum, you need a thinner mattress.
- Mattress in, no extra topper
- Measure from the mattress surface to the rail top
- Compare against the manual's minimum, usually about five inches
Watch out. This is the mistake that undoes all the other safety work. A thick mattress plus a topper can leave almost no rail at all. Use the thickness the bed was designed for. -
Full safety walkthrough, then a monthly reminder
Go over every bolt one final time with the wrench. Shake the whole bed. Then set a monthly reminder to re-check the bolts, because they loosen with use.
- Every bolt, one more lap with the wrench
- Shake the bed hard at the top
- Monthly phone reminder to re-tighten
Tip. Bunk bed bolts genuinely do loosen — a bed with a child climbing it is a structure under constant cyclic load. A monthly two-minute check is the whole maintenance plan.
If something has gone wrong
The frame wobbles side to side
Bolts are not tight enough, which is very common because an Allen key cannot generate enough torque. Go around every bolt with a socket wrench or wrench. Also confirm the diagonals are square and all slats are fitted and secured.
A bolt hole does not line up
Loosen every bolt on that bunk a couple of turns. The frame will shuffle and the bolt will go in. Then retighten everything from the center outward. Never drill a new hole in a bunk bed.
I am missing a bolt
Stop and order the exact part from the manufacturer. Do not substitute a hardware store bolt — length and grade are engineered for this load. Every major brand ships bunk bed hardware free and quickly.
The guard rail gap looks too big with our mattress
Your mattress is thicker than the bed was designed for. Use a thinner one. This is the single most common bunk bed safety failure and no amount of tightening fixes it.
The bed creaks when my child moves
Do a full wrench lap. Then check for wood-on-wood contact at the slat ends and add felt pads. Also make sure the bed is not touching the wall — that knock is often mistaken for a frame creak.
Can I separate it into two single beds?
Only if the manual says so and only using the parts supplied for it. Many bunks convert, but some posts are not designed to be bed legs on their own.
Words you will see in the manual
- barrel nut
- A metal cylinder that drops into a round hole in a crib or bed frame, with a threaded hole running across it. The bolt comes in from the side and threads into that cross hole. If the cylinder is rotated even slightly, the bolt cannot find the thread — turn the slot on its end with a flat-head screwdriver until you can see straight through it.
- guard rail
- The barrier along a top bunk. Needed on both sides, including the wall side, and the gap above the mattress must meet the manual's minimum.
- plumb
- Truly vertical. A gate that is not plumb will not latch reliably.
- square
- Describes a frame whose corners are true right angles. You check it by measuring both diagonals: if the two numbers match, it is square.
- stud
- The vertical timber inside a wall, usually every 16 or 24 inches. It is what you screw an anti-tip bracket into. Drywall alone will not hold furniture.
- anti tip
- A strap or bracket that ties furniture to the wall so it cannot fall forward. Required on anything taller than it is wide, and on every dresser in a home with children.