Furniture

Knockdown Bed

Brief

A modern platform bed with a headboard that provides good back support for reading. Storage space behind the headboard and underneath the platform was also a requirement.

Tools

  • Skilsaw
  • Sander
  • Orbital Sander

Role

  • Furniture Maker

Year

2012

[Fig01] Photomontage showing bed structure.

Design

This bed has a wide skirt and a foot of storage space behind the headboard. It's designed as a set of interlocking plywood beams. Each beam is made of 3 nearly identical 1/2 inch 7 ply furniture grade Baltic Birch pieces glued together. The joint at the criss-crossing glue-laminated beams is a variant of a double dado cross half lap. With minimal screws, the bed is held together by gravity. It's unstained, the final finish is just clear varnish on the baltic birch veneer.

[Fig02] Massing Study

Context

Our master bedroom is in a converted garage with a layout where 2 doors prevent the placement of night tables on either side of a standard width bed. Storage has to be behind the headboard or under the bed.The concrete floor slab is carpeted for noise and insulation.

There are very few ready made beds with storage behind the headboard and underneath the sleeping platform. Hiring a furniture or cabinetmaker would be cost prohibitive and I didn't see anything out there that was close to interesting.

The initial idea was worked out in Sidefx Houdini. The model is a massing study that gives an idea about how the a king size bed would look through a camera relative to the back wall. The headboard was clearly a concept with not much thought on how 2 angled boards would stay put and serve as backrests.

Construction Drawings

There wasn't a great way to convert the Houdini model into something useful in the real world like CAD shop drawings. I was too inexperienced to attempt a CnC approach to cutting plywood.  

I sketched cut diagrams on graph paper to scale so I could plan out the number of boards I needed to purchase and cut at plywood store's table saw.

[Fig03] Longitudinal Spine
[Fig04] Cross Ribs
[Fig05] Platform Skirt Overlay

Built-up vs Carved Beams

I knew that compared to regular lumber, laminated wood was strong and dimensionally stable through heat and humidity cycles. Also, beams combining 2 or 3 sheets of plywood would have enough thickness to stand upright.

[Fig06] Testing beam assembly

I had seen images of intricate Japanese joints designed to lock perpendicular beams in place. The joints require great skill to precisely carve and chisel. I cutout the joint on each flat sheet of plywood with a jigsaw and chisel. I created the interlocking double dado joint when the pieces get laminated together. Each 3/4 inch thick Europly laminated plywood had 7 plys of thin wood, the combined pieces are 21 ply, so there's significant redundancy.

The beams were laminated together with white carpenter's glue overnight. The assembled beams were routed and sanded to smooth out any splinters and rough edges. Finished beams were sealed with a clear varnish to protect the plywood.

The design of the platform and headboard was refined along the way. The platform used interlocking pieces to prevent sliding. 21 plys are seen on the edge but the sleeping section is only 1 7-ply piece thick. The pieces would have been too heavy to move if they were full thickness throughout.

I was not able to wedge the headboards into the platform. Instead the final design is supported on the back and rests on the platform, locked to prevent tip-overs in an earthquake.

[Fig07] Time Lapse of Bed Assembly

Assembly

Two people are needed to assemble or disassemble the bed. The pieces can be slotted in position without tools. Due to the size and weight of the components it's harder to man handle than an equivalent sized Ikea bed.

[Fig08] Final Bed

Conclusions

I began the project trying to solve a personal problem with basic woodworking skills and tools. If I were to do it again a few places to improve come to mind.

  • Over-engineering - The design is over-engineered with 2l-ply components, 14-ply pieces might work equally well with less labor, materials, and weight.
  • CNC cutting - All the pieces are cut from a North American standard 4x8 sheet. CNC cutting could create better fitting pieces with less waste.  
  • Headboard to platform connection - Precise slots could allow the headboard to slide into the platform tightly at a slight angle and simply the design tremendously.

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