Building a garden workshop

This is great, my own workshop and I got to build it myself. I’ve been looking forward to this for years and now I’m there. I still have a little to do including a workbench, shelving, storage and running power but the essence is there and I’d like to share how I got there.

If you want to build your own flat pack garden workshop then read on to see how I did it. If you’d like to build a workshop from scratch then this post will also be worth reading: How to build a garden workshop from scratch

I had a reasonable size space to work with for this project but decided to go for a 12 x 10ft build. This would allow me to leave a reasonable amount of space between the workshop and the garden boundary. I was tempted to squeeze in a couple of extra feet but this would leave it very close to my mulberry tree. It’s strongly advised not to build near trees or bushes as these over time can grow into the building and cause damage.

Once I had decided on the size I needed to choose an actual building. Was I going to build this myself or save some time and buy a flat pack one? On this occasion I purchased a building from which (in my opinion) is one of the best websites for customisable garden buildings and they offered 10% off the first purchase.

Before purchasing a garden building I recommend doing your research and reading online reviews to make sure you are buying something that is good quality and right for you.  There are independent websites such as What Shed that do a really thorough Garden Buildings Direct review online.  Sheds and outdoor buildings are pretty costly so you want to make sure you buy right the first time.  That website also has discount codes for Garden Buildings Direct so it’s definitely worth checking out to help you make the right choice and save some money.

So the building was on the way but I needed some solid ground to put it on. I knew I had a few options here but I had to consider what I could actually achieve on my own with the tools I had. I ended up going for a paving slab base. This would offer me a robust, strong and level base to build on. This part of the project was probably the most physically challenging but is actually quite easy in terms of skills required. I’d repaired some of existing patio before so I had a little experience but never attempted anything of this size. Here’s how I did it.

Building a garden shed base or patio


For the base there were a few materials required to ensure a good strong surface for the shed to sit on.  These included:

  • MOT Type 1 Sub base – This stuff is perfect for creating a solid surface to lay your slabs.  It consists of 1mm – 40mm jagged stones that compact down to form a strong level surface.
  • General purpose cement – Combined/mixed with sharp sand to make your mortar mix (Concrete)
  • Sharp sand – Mix with cement to make mortar.
  • Paving slabs – I didn’t use anything fancy here, just a basic slab to support the shed.


To complete this base you will need a few basic tools and one not so basic, the cement mixer.  You can try mixing the concrete by hand but for the amount required it’s much easier to buy or hire a cement mixer.

  • Wheel barrow – Moving your materials around the garden
  • Cement mixer – Mix the mortar.  I purchased one and now rent it out via Fat Llama
  • Trowel – For applying the mortar to the base
  • Shovel– Round edge shovels are ideal for digging into the MOT materials.  Flat edge shovels or spades are better for moving larger loads
  • Compactor – I created my own out of a sledge hammer and an old slab but you can also buy or hire one
  • Spirit level – The larger the better.
  • Rubber mallet – to tap the slabs into place
  • Tape measure – 8m is ideal
  • String –  for marking out a level area
  • Wooden pegs – for marking out a level area
  • Gloves – hand protection

Step by step guide for how to create a shed base

  1. I started by marking out the area with some wooden pegs and string. Square this off by measuring from corner to corner until both lengths are the same.
  2. Level out the area. This took a lot of digging and back pain but was essential to the overall build.  The overall area needs to be flat but also requires a bit of run off for surface water.  So don’t worry too much about levelling this perfectly.
  3. Fill the area with the type 1 MOT and level off by walking over the whole space with tiny stomps steps. I used enough for about 60mm depth. In some cases you might need to go a little thicker but as my soil is mostly clay it wasn’t essential.  Clay is a very tough soil that hold weight well.  To calculate the amount of Type 1 MOT you require you can use this calculator.
  4. As you can see I had a little help. 
  5. I used a roller and makeshift compactor to create a nice flat surface.  I used a piece of wood and spirit level to get this as level as possible.  It’s important to compact the sub-base as much as possible to make sure the base doesn’t sink when all the extra weight is added after.
  6. Mix up the concrete. I used a cement mixer because the thought of mixing all that in a wheelbarrow or mixing tray was very off putting. You can purchase one for about £230 or hire one for about £15 a day. The mix should be about 4 parts sand to 1 part cement. Water is added after to make a wet mix. There are plenty of YouTube videos to help if you get stuck.
  7. Using a large blob in each corner of the slab and levelling off with a large spirit level. Each slab should have about a 6mm gap and level with the last. To get a nice level base you can use a long piece of wood to lay across the slabs and gently tabs each into place with a rubber mallet.
  8. Ensure you follow the string line as you go along which should have a 2cm drop for every 1m.  This is to allow water run off.
  9. Once all the slabs have been laid leave to go off for 12 – 24 hours. Now to fill the gaps. Simply mix some slightly damp sharp sand with some cement, about a 1 part cement to 2 or 3 part sand. Then using a scrapper push the mix into the gaps and level off with a small pipe or similar shaped tool.

That’s it for the base. Now onto the workshop. It was relatively easy to put this building together as the instructions were pretty clear.

Garden Buildings Direct promo

Building a flatpack shed step by step guide

There are a few key points to take note here to ensure a good sturdy build.

  1. Ensure the base is completely level. Any slight unevenness will affect the way the walls and roof fit together.
  2. Use two drills. One for drilling pilot holes and one for screwing. This will speed up the build.
  3. When screwing the walls together, only use a couple of screw to start with as it’s very likely you will need to adjust each slightly.
  4. I managed to build most of this on my own but there were a few times I required an extra hand. Thanks wifey 🙂
  5. Check all the parts and arrange into piles before you start. This makes it easier to find everything and speeds up the build.
  6. Don’t buy cheap drill bits from eBay. I went through a pack of 10 in two days!
  7. Avoid rainy days. Ideal time to build would be in the summer. I was caught out by a couple of rainy days that prevented me from building. You can’t fit the roof materials when wet.
  8. Think about what floor you want. I went for the cheaper floor on this model but wish I’d gone for the thicker flooring. This was about an extra £150 but I think it’s worth it. I added a cheap laminate floor just to strengthen it up a bit. This cost about £50.

So far This is just a big empty space. The next stages for me to finish this project and make this a fully operational workshop will be:

  1. Add some security. I won’t be putting anything in here until I’m happy it’s protected. I’ve purchase a decent smart home Yale alarm system, home security lighting and triple bolted doors.
  2. Workbench with storage. I’ve got some great ideas for a workbench I intend to build myself. Stay tuned for more on this.
  3. Fit lighting and electrical points. Not too sure how this is going to pan out as I’m not a big fan of electricity as you can read in one of my other posts.
  4. A suitable path. At the moment I just have some loose paving slabs laid in the grass but this isn’t ideal so I’d like to lay a proper path with a nice border.

That’s it for now but as always, if you’d like to know more just drop me a mail.

Garden Buildings Direct promo

If you liked this post then take a look at some of my others for some great ideas.


  1. The gardensbuildingsdirect link points to a generic dns page suggesting that the site doesn’t exist any more.

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