Semi Modular Semi Flat Pack Office Storage With Integrated Filing Cabinet




Introduction: Semi Modular Semi Flat Pack Office Storage With Integrated Filing Cabinet

I needed a storage unit for my office. I was unable to find a unit that I could buy that fitted and met my requirements. I considered modifying flatpack units but this didn't seem viable either. In the end, I chose a hybrid of a custom-made carcass to fit off-the-shelf doors.

The unit was designed with the following requirements in mind;

  • Needs to fit the space i.e. wider than the 'step' but narrower than the wall.
  • Needs to make as best use of the space as possible.
  • Doors to keep dust out.
  • Incorporate a filing cabinet.
  • Be installed into an otherwise finished room that was in daily use.
  • Not be fine cabinetry.
  • Avoid an awkwardly placed socket.

This list of requirements gave rise to the Frankenstein cuboard I'm about to describe to you. Half built-in, half homemade flat pack, half shop-bought flat pack. Total nightmare. In other words, two sides are made in the style of flat pack furniture, whilst the other two more resemble a proper built-in. Easily the most restrictive requirement turned out to be working in a decorated room which was still in daily use. This resulted in designing a modular unit, where each module could be fully finished in the garage and brought upstairs to be installed with limited dust & mess.



  • 18m Plywood - 2 8' x 4' sheets (1220mm x 2440mm).
  • 'U' section extruded aluminium channel. Length: 1000mm, Size: 22.2mm x 22.2mm x 3.2mm
  • 'L' section extruded aluminium angle. Length: 1000mm, Size 19mm x 12.7mm x 3.2mm
  • Primer/Undercoat - White matt water based.
  • Top Coat - White semi-gloss water based.
  • Wood Glue.
  • Wood Filler.
  • Clamps
  • Steel Angle
  • Masking Tape

Bought in Items

  • Doors - Ikea Billy
  • Brackets - generic angle brackets from a local DIY store. (Screwfix)
  • Screws - 4mm wood screws of varying lengths.
  • Wall Plugs - Your choice as required. I required for both Plaster & Brick Walls.
  • Foolscap Drop Files


  • Hand held circular saw
  • Tape Measure
  • Pencil
  • A long straight edge
  • Steel Rule
  • Calculator (Optional)
  • Profile marking gauge (If required)
  • Coping Saw (If required)
  • Rasps & Files (If required)
  • Brad Nailer
  • Speed Square
  • Router with Flush Trim Bit
  • Laser Level
  • Masonry Drills - 6mm
  • Metal Drills - 3.2mm, 5mm, 11mm
  • Wood Drills - 4mm
  • Counter Sink Bit
  • Hacksaw
  • Metal Files
  • Random Orbital Sander

Step 1: Marking, Cutting, & Preparation

In order to reduce the material costs I had ordered the material as full 8' x4' (2440mm x 1220mm) sheets along with another few projects. So the first step was to break the sheets down into more manageable sections, but in a way that meant I didn't have to immediately start with cutting the more high precision pieces.

I only really had one place within my garage where I was able to lay down the full sheets, so I started with the sheet on the top, reduced that into sections and then moved onto the next one in the stack. I used polystrene sheets saved from packaging to put under the sheet being cut and protect the sheet below from the saw blade.

How to cut the sheets up will vary on the shape, size & design of your project, and also the size of sheet that you buy. I chose the large awkward sheets as the cost is almost the same as the sheets that are 1/4 of the size.

Step 2: Mass Production

A significant portion of the unit was to be made from long, thin strips which would then be assembled together. You might have noticed that suddenly the colour of the plywood has changed significantly... Unfortunately the material that I was delivered was of very poor quality. The surface was rough, the thickness varied by up to 2mm in places, there were large pockets & air gaps such that when I cut many of the strips, the plywood literally just fell apart. I already had some 18mm ply left over from a previous project which was *just* of sufficient length and width to make the more visible pieces from. So I chose to try and make as many of the visible outside surfaces from this better material and save the new stuff for the inside where possible.

Ok, so onto the actual step... I had the cut a large number of long thin strips of plywood without a table saw. Using the floor again as a work surface (placing sheets under the board to protect the surface), I used another piece of ply with a known good straight edge as a guide. This was placed on top and could then be used as a guide for my hand-held circular saw by leaving the correct amount of the sheet below sticking out.

I was going to have to do a lot of these so took the time to work out how much the blade in the saw was offset from the guide edge. For me this was 151mm. This meant that if I wanted a strip 71.5mm wide I would need to leave 22.5mm of the board I was cutting sticking out from the guide. By clamping a block to a steel rule, I was easily able to set and double-check this at both ends of the cut. With careful setup & making sure the guide didn't move, I was reliably able to cut all pieces to within 1mm of the desired widths. Once I had set everything up, I made sure to stand on the guide piece, using my own weight to essentially clamp the guide to the piece being cut, preventing it from moving as I moved the saw along the long cuts.

Step 3: Cutting Out Profiles

The unit needed to fit around the skirting boards so I used a marking gauge to record the profile of the skirting and transfer this onto the side panel. Using a series of saws & files I cut the marked shape from the corner of the piece. Took it upstairs for a triumphant fit and... nope not really :-( Not a great fit. Turns out the floor and the walls were no where near at right angles, which I didn't check and am assuming threw everything off.

Recovery - I took a pencil, layed it flat on the floor and used this to draw a line along the bottom of the side panel when it was pressed up against the wall. I could then use this line as a guide to cut the bottom to match the floor. The same trick wouldn't work for the skirting board as I couldn't get the pencil in. By using a large Penny washer I was able to use the same trick and get a line that I could use as a guide for cutting the required shape. By doing this I was able to recover this to a good enough fit, only really the height that was still and issue.

Step 4: Assembling the Major Pieces

The body of the unit was made from 5 pieces, each of which was made up from between 2 & 3 bits of plywood glued together. Because I had done the cuts with a circular saw, I was happy that the cuts were square enough to use for gluing up. I used wood glue for the joints, with nails to hold the glued joint in position & closed while the glue dried. Once this was done, the edges were finished with a flush cutting router bit and filled, then sanded.

Step 5: Preparation, Painting & Repair

Painting, my nemesis! I've had nothing but issues with oil based paints made in the last 10 or so years and this just seems to be getting worse. I can get a lovely finish but the clean-up is a pain and the smell isn't great. Worst of all I can't find a white that will stay white for more than a week or so, a few months at best. It just doesn't seem to be made the way it used to be, where the excellent results were worth the smell and clean up. It was time to try the modern water-based alternatives. I was lucky here in that wanted a semi-matt, eggshell finish and not full gloss for which I have found the water-based paints to be excellent. No smell, easy clean up with water and drying times measured in minutes, meaning in the space of a few hours I could do multiple coats.

It was at this point however that the earlier issues I had with the plywod quality came back to haunt me. In many places as soon as I applied the paint, the surface layers of the playwood blistered and lifted away forming very noticable bubbles. By aggressively sanding, & filling, then sanding I was able to deal with most of these without too much trouble. I did a few cycles of coating with primer, seeing the terrible blemishes, sanding, painting, seeing a load terrible blemishes etc

Step 6: Fixing a Mistake

Another issue! Of the two walls this cupboard would sit against, one of these was very uneven. Perfect at the bottom (where I measured) and perfect at the top (also where I measured) and far from perfect in the middle (where I didn't measure). I had already cut this piece to size and assembled it so had to get a bit creative or it would be a case of ordering more plywood :-(

I used a variation of the washer & pencil technique used before. I held the piece in position against the wall, making sure that the finished surface was vertical and then using a washer, drew a line that was parallel to the wall and its massive bulge. I then affixed a strip to the edge of the plywood and roughly cut it to width. I used the router with a flush cut bit to cut it flush with the surface of the plywood.

Now by using the same washer and a short strip of wood as a guide, I made a line parallel to the first, this will be exactly where the wall was when I drew the first line. The first line was one washer width away from the wall and the second was one washer width back in the other direction. This gave me a line for where I needed to cut the new added strip back to. By doing it this way and measuring it in-situ I was able to end up with the piece wider and the correct shape, but not changing its position relative to the wall and the rest of the cupboard. This was important as this piece supported one set of the door hinges so would affect the door width and the rest of the unit.

Once I had the line it was simply a case of cutting, planing & sanding to the line. Then the usual process of sand, fill, sand paint and then the added strip was invisible with no evidence of my mistake :-)

Step 7: Trial Assembly

Next was to trial assembling the pieces in place. This would confirm that they fitted correctly, let me cut the top front piece to length (which I had left over size slightly, see the 3rd/4th pictures), and set the height of the kickboard.

The kickboard was made from two overlapping strips of ply; the front one fitted to the bottom of the unit and the back one to the floor. This is to account for any unevenness in the floor. I used a spirit level & a laser level to align the unit. It would almost hold itself in place, but for some assistance I fitted a couple of temporary brackets to the wall.

Step 8: Assembling the 'Flat Pack'

I had bought some brackets from the local DIY shop to fix the unit to the wall but when I fitted them it didn't really feel solid or secure. Of particular concern was the left hand upright which directly supports a door. I decided to make my own additional brackets to supplement the shop bought ones. These were the perfect size, being long enough to allow me to get access to screw them to the wall but not so long that they protruded into the cupboard and would be visible. This however meant that they were only fixed to the wall at the end, far away from the cupboard upright, which resulted in quite a lot of flex.

I decided to make very similar brackets of my own but put the wall fixing hole as close into the corner of the bracket as possible. This would result in the two different types of bracket working as a pair, the shop bought ones stop it flexing out, while my homemade ones stop it flexing in. The shop bought ones were also good as they had adjustment built in, so I can use these to fix down the final position, then mark and drill for my non adjustable DIY versions. Because of the position of the screws in my DIY brackets, the only way to access the screw holes to drill & screw would be to make a holes through the cupboard, however I had a cunning plan to hide these. I decided I wanted two DIY brackets to supplement the two shop bought ones, as the doors I chose have 3 hinges, I could use the hinge brackets to hide the required holes. I then made a fill-in piece to stop dust and dirt accumulating between the side panel and the 'step' that the cupboard will house as I won't be able to clean in here once assembled.

Now I know how wide & tall the unit will be once installed I could paint the area, the edge could be fairly rough as it would be covered by the 18mm plywood, so as long as the 'roughness' of the edge was less than 18mm wide it would appear perfect when the unit is installed.

Just worth noting that it would make much more sense to use masking tape but at some point, a previous owner of the house hasn't followed the proper procedure when painting fresh plaster so unfortunately masking tape is a big no for me as I can almost guarantee that huge pieces of paint will come away when I try to remove the tape.

Step 9: Final Painting

My original plan was to avoid any kind of sanding, painting or 'messy' work in the room, as this was otherwise finished, decorated and being used on a daily basis. As the project progressed, with the success I was having with the ease of use of the water-based paints I decided that I could probably get a better finish overall if I did the last coat in-situ. This would help to cover any joints and let me glue and nail the top and bottom to the side, avoiding brackets.

By lightly sanding before installing, I could do one final coat after it is installed without making mess our subjecting us to days of paint odour. This also had the advantage of my having to just be a little less careful when handling the units as no longer would any little knocks or scratches be permanent. The walls either side had taken a bit of a beating throughout all the trial fit & assembly process but this was no issue as I knew I had spare paint left over from painting the room, and masking onto the cupboard would be no issue. I managed to avoid getting as much white paint as possible onto the walls without masking them by tucking strips of brown paper beind the cupboard.

Step 10: Doors

I didn't much fancy trying to also make my own doors so I had opted to use shop-bought doors (from Ikea). It was just a case of copying the hinge mounting holes from another shop-bought Ikea unit. I started with the middle door and then, using the laser level, set the holes for the doors either side to match this one. You can see in picture 3 how the hinge will cover the access hole for tightenting the DIY wall mounting brackets.

Step 11: Filing Cabinet

As well as being "homemade flat pack", the unit was intended to act as shelves and a filing cabinet. As well as not being able to find anything to buy & modify the correct sizes, I had never seen this filling arrangement. I have been constantly annoyed over many years by shop-bought filing cabinets being frustrating to use. They always seem to have shockingly low storage capacity for their size and, due to stability issues, the drawers open less than 1/2 way, sometimes less than 1/3.

I had considered two side-by-side rails running from front to back of the cupboard, but due to issues on how to support the rails that would be floating in free space in the front centre of the unit, I decided to go with the unconventional sideways approach. This would use two extruded Aluminium profiles as rails for the files. The back rail was first. I drilled a hole through, one at each end 5mm for the 4mm screws. The front hole of each of these pairs was then enlarged to 11mm to accomodate the screw head and give access for a screw driver. I measured the required height for this rail based on the foolscap folders I had bought and drilled the left hand hole. I fixed the channel to the wall and then using a spirt level, set the right hand hole from this.

The front rail was a bit more involved. I cut two short lengths from the end of the 'L' Aluminium angle the same length and the short leg of the unequal angle. Into the short leg of these pieces I drill and tapped a hole for an M4 thread. Threads in aluminium are never particularly strong but this just need to hole the rail in-situ, the bracket takes the load, this just stops it falling off the bracket. Into the longer leg I drilled a 4mm hole and counter sunk this for a wood screw. This will fix the bracket to the cupboard. I then cut the front rail to length.

Using a piece of wood and a spirit level I set each side level relative to the rear rail in turn and screwed it in place.

A light coating of wax (from a candle) to the top of each rail finished then job. It was then a case of putting the files in and transferring all the paperwork.

Step 12: Time for Shelves

I cut the shelves by hand from the remaining pieces of plywood using a belt sander to fine tune the shape to get a good fit. The was of particular importance in the left hand narrow cupboard where it fits into the corner of the room as this was far from 90° and even varied quite considerably from the top to the bottom of the cupboard. Because of this, on the back edge of every shelf I made sure to write its position and orientation. I only did one coat of primer on this edge so this was always visible.

I had debated for quite a while what to use to support the shelves. I wanted a metal shelf rail with repositionable clips but these were either very expensive or out of stock. I quite liked the recessed ones where they sit in a routed strip so when installed they sit flush with the inside of the unit but I hadn't routed these before the cupboard was assembled so this was a no go.

In the end I decided on using some pieces of Ash I had around to make battens to support the shelves. I felt that this natural wood would contrast with the vast areas of white of the rest of the unit. These were made from some off cuts from previous projects which hadn't been used due to blemishes or knots. I managed to cut most to avoid these as far as possible. Firstly I cut them to length by hand and then cut the strips to width using a small benchtop band saw. They were finished on a benchtop belt sander. A hole for a 4mm wood screw was drilled into each end.

I used an off cut of plywood as a spacer to one end of one rail. The other end of this rail was then set with a spirit level from this with the front of the shelf ever so slightly higher than the back (this will stop things rolling and falling out). The other side used the shelf as a guide. I put the shelf in place lifting it up untl the spirit level indicated it was level and while someone supported the shelf I was able the screw the bracket in to set the shelf level at this height. I chose to do this so that any imperfection might result in the shelf not being perfectly level but it would sit and not rock. If one of the battens was slightly out, or more likely, if I set the battens level and the shelf was warped, it would rock. This sets the battens to accomodate any imperfections or warp in the shelves, so they felt solid. This was more of an issue in the smaller left hand cupboard where I was fixing into a brick wall. Depending where you drill and exacly where on the brick your hole lands, it can tend to wander a bit. This method let me fix the left hand batten as close to level as I could and not worry about the holes in the brick wandering as I was setting the other batten (screwed into wood) to match the batten and not truly level.

Step 13: Shelf Install & Removal

It was tight but even being a good bit (more than 4 inches) wider than the opening, all of the shelves can be removed and reinserted individually if needed.

Step 14: Finished!

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    Liz in AL
    Liz in AL

    16 days ago

    A nice job on what turned out to be a tricky set of requirements! I was especially happy to see you anchor the cabinets in place. Should you ever need them, you can get box-bottom hanging file folders (for those fatter-than-expected files) as well as hanging file pockets (with closed sides) to corral the odd small papers (e.g., receipts).


    Reply 16 days ago

    Oh yeah, they would be perfect, I've got a few thicker things already that could benefit from fatter folders. Plenty of spare space left to add a few. Thanks for the tip!


    16 days ago

    Amazing idea!! Genius thank
    You for sharing this


    Reply 16 days ago

    Thank you :-)


    17 days ago

    Such impressive work! and so organized!


    Reply 16 days ago

    Thank you, I can assure you it is just well hidden mess & chaos! ;-)


    22 days ago

    Wow! That looks SO nice :)


    Reply 16 days ago

    Thank you :-)