Bunk bed

From DIYWiki
Bunk bed with decorative rails

Bunk beds are popular with kids, and very practical. They're not a difficult DIY project to make. DIY beds can be substantial and high quality, or very low cost, and can be customised to suit.

Timber framed bunk beds are described here. Timber construction is accessible to all DIYers, needing only basic diy tools.


Construction

Timber bunk beds normally consist of:

  • Wood frame
  • Bracing
  • Side guard rails for top bunk
  • Ladder
  • Bases for mattresses

Wood frame

Asking what size to use is like asking how long is a piece of string. The larger the wood, the stronger and more durable the structure will be. Absolute minimum sizes are 2x2" or 1.5x2.5", but these sizes need reinforcement at all load bearing joints to be safe, and attachment to a wall to avoid sideways movement that can split joints. Larger timber is much easier and recommended. 2x4" makes a good solid framework.

Bracing

Bracing is required to stop the framework leaning over and breaking up. The main options are:

  • small wooden bracing pieces in all corners (Diagram 2)
  • a long wooden bracing strip at apx 45° on each of 3 sides (Diagram 3)
  • 3mm thick steel corner braces
  • Fixing to a wall can also be used as suitable restraint

For details of these bracing options, see Brackets


Guard rails for top bunk

The top bunk needs side guard rails to prevent someone falling out of bed in the night. The options are:

  • Full length wooden strips (eg 4x1)
  • 2/3 length wooden strip with short upright post on one side - the projecting corner should be rounded (or padded) for safety - and a full length strip the other side
  • Plywood cut to form an L (with rounded corners) (Diagram 4)
  • Crenellated plywood fixed to the base rail (Diagram 1)
  • Rope rails are not recommended, as they can stretch and sag, ceasing to be effective, and they put high levered loads on the woodwork.
  • Metal pole rails could be used, but they would need to be substantial enough not to bend when jumped on

Ladder

There are a few different ladder construction types:

  • 2x3 CLS with treads screwed onto the back or front of the uprights
    • Use 2 fixing screws for every fixing point
  • 2x3 with treads screwed between the uprights
    • supporting brackets are necessary on every rung
  • Sheet ply with tread holes cut out
    • Ply must be thick enough to pass the final load test
    • Holes should be small enough not to weaken the wood
    • Hole edges should preferably be rounded a little.
    • Extra smaller holes can be dotted about for a funky appearance
    • Ply should have cleaned up edges and be well varnished to avoid splinters.
  • extra wood can be fitted to the rear of the holes to widen the depth of the treads (Diagram 5)
  • 2x3 CLS or similar with pole treads inserted into holes drilled in each upright

More ladder points:

  • 2x3 CLS is convenient for ladder making, as it has 4 rounded edges ready machined, is low cost and chunky.
  • Smaller timber is liable to split at screw fixing points.
  • Splits are bad news in wood ladders, so all holes should be pilot drilled.


Bases for mattresses

The main options are

  • Sheet chipboard - 3/4" is best, 1/2" is usable.
    • ventilation holes optional
  • Wooden slats - 5x1 is good
    • Slats may be close spaced for best comfort, or 2-3" apart for economy.
  • 3'x2' 18mm flooring chipboard pieces.


Joints

Options are:

  • Timber butted, with heavy duty metal bracing
    • simple and tough
    • works with all timber sizes
  • Rebated joints
    • more work, but a neater finish
    • requires larger timber size
  • Timber butted & through bolted
    • simple
    • only strong enough with larger timber sizes
  • Plastic blocks used for kitchen cabinet fixing
    • fixes close to end of timber, reducing strength. Not very pretty.


Decoration

There are various ways to turn a basic bunk bed into something more decorative.

  • Round over the tops of timber rails.
  • 45° edges are easy to do with a plane, but not as pretty as rounded edges.
  • decorative infill panels may be painted, cut or carved
  • Turn a decorative end on the tops of the uprights, or attach large round knobs
  • Plywood infill panel with assorted holes dotted about (a couple of inches and bigger)
  • Decorative bracing
  • Extended uprights & a fabric canopy. Fabric should be open weave in case it falls on the sleeper - netting is good.
  • Thick glassy varnish - several coats with sanding between each
  • Carve the horizontal rails to fancy shapes - use large enough sizes not to compromise final strength


Optional extras

  • Gadget shelf for top bunk - with sides to avoid items falling off
  • Low voltage coloured LED Lighting built in
  • Drawers under lower deck on castors or sliding feet


Economising

Some options when cost needs to be minimised:

  • Omit 3 of the 4 uprights, fixing the woodwork to the walls (in a corner).
  • Omit 2 uprights, again fixing to the wall. A corner position is not needed this time.
  • Placing the ladder at the foot end reduces work and material use slightly.
  • A vertical ladder attached to the main frame saves on wood but affects safety, so is not recommended.
  • Assorted scrap can be used for slats. It should be sorted into widest at one end, narrowest at the other. If not sorted, different widths sag differently under load, causing uneven support. Don't use pieces too narrow or thin to stand on safely. (Prettier slats can always be bought later.)
  • If you already have rough sawn wood but no plane, it can be used covered with cloth (see finish section below). Cloth can be glued or stapled.
  • Omit the lower deck, putting the mattress on the floor. The uprights then need to be fixed to the floor.


Finish

  • Varnished wood - durable, easy to clean, chips don't show too much - avoid tinted varnish
  • Bare wood - minimum work & cost.
  • Painted - oil based gloss makes for easy cleaning. Will chip in time, so keep a little spare
  • Painted patterns - fun and kids love to join in - chips less visible - animal prints, battenberg, wild stripes, anything
  • 3d painting - colours fade from one tint to another. Requires careful use of a sprayer. Can look really good if done well, but is not simple to make a good job of it. Can be overpainted if it doesn't turn out well.
  • Metallic or pearlescent paints. Metallic needs varnish as a protective coat.
  • (Patterned) cloth folded over timber and stapled in place. Gives any wanted pattern quickly. Very hard to clean. Not hard to replace. Thicker cloth such as carpet can also be used.


Safety

  • All cut ends should be rounded off or trimmed at 45°
  • When pilot drilling into knots, use a bit 0.5mm larger than usual. The screw then cuts less thread depth into harder wood, with a good result.
  • check there are no splits on the timber ladder
  • Load test the ladder and bed with twice the required load rating before use.
  • All joints should be screwed. Nails aren't suitable.
  • All timber should be planed, sanded or covered with cloth to avoid splinter injuries. The simplest way is to buy ready planed PAR or PSE timber, then only cut edges and corners need tidying up.
  • All screws should penetrate over an inch into the wood they fix to.
  • All exposed timber edges should either be rounded off or trimmed to 45° by removing a few mm along the corner edges. This can be done with a basic plane.


Diagrams

 ____________________
|  ___   ____   ___  |
| |   | |    | |   | |  
|_|   |_|    |_|   |_|

Diagram 1: Crenellated plywood side
  __
 / /
| /
|/

Diagram 2: Small timber braces
||     /||
||    //||
||   // ||
||  //  ||
|| //   ||
||//    ||
||/     || 

Diagram 3: Long bracing strips
 _____________
|____________ \
             \ \
              \_\

Diagram 4: ply guard rail
   _
  | |
  | |  <--- ply sheet
  | |
  | |
 _     <-- foothole
| | |  <-- more ply attached to rear of sheet
|_| |      at base of foothole
  |_|

Diagram 5: Deepening treads in sheet ply

See Also