How to build a shed base

Introduction

All garden sheds must be assembled on a firm and level base to give the shed a good foundation and maximise the longevity of the building. Without a firm and level base, you may find that that the shed can drop out of square causing problems with doors not closing or the roof twisting potentially leading to water ingress. An incorrect base may also invalidate any product guarantee and therefore is it essential that this part is done first and done well before assembling the shed. 

 

Where to put your garden shed base?

Please consider the following when deciding where to put your garden shed base: 

  • Ensure you leave access around the shed for iinstallation, and future maintenance / treatment;
  • Consider surrounding areas / foliage that may come into contact with the shed such as trees etc; 
  • Take into account the shed comes with a roof overhang and so don’t build too close to walls or fences;
  • Test where drainage water runs in your garden – if it runs to the area where you plan to put your shed it could cause water damage to your shed or base in the future. 

 

What size should my garden shed base be?

There are different schools of thought for the size of the base with some companies recommending a base larger than the shed floor size to give some room to move the shed and to give an element of margin for error and some companies recommend a shed base be slightly smaller so water cannot pool around the base or floor. 

Our advice is simply for the shed base to be the exact same size as the shed floor. We would advise you to consult with the shed company you go for on the exact size of the floor, which may differ to the dimensions of the shed and what they advertise as the size of the shed on the website. An 8×6 shed may not have an exact 8ft x 6ft floor size. 

Our Power Base range will fit the shed floor perfectly.

Shop Power Shed Base

 

Which type of garden shed base should I to go for?

There are a number of options for shed bases and customers often ask which is the best shed base to go for. All of the following methods are suitable and which one you choose depends on budget and skill level. For larger sheds a concrete base would be the strongest but also expensive and time consuming to prepare. Our Power Shed Bases are suitable for all of our sheds and is the easiest type of base to construct. 

The three recommended bases to go for are either:

  • Power Base;
  • Paving slab shed base;
  • Concrete shed base. 

 

How to install a Power garden shed base?

Number of people installing: 2 

Approx time to produce (if an 8×6): 1 hour 

Tools required: Spirit level, tape measure, drill, lump hammer 

  1. Roughly lay out the components for the wooden frame Power shed base. You will have a separate wooden frame for every shed floor panel.
  2. Measure the timber and mark out the positions for the shorter cross bearers spreading them out evenly between the larger bearers.
  3. Screw the framework together with the 90mm screws provided. We would strongly recommend pre-drilling the timber to avoid it splitting.
  4. Move the Power shed base to where you want your base to sit.
  5. Using a spirit level find the highest corner of your Power base and with a lump hammer, drive one of the steaks into the ground in the corner (on the inside of the wooden frame).
  6. When the top of the steak is just below the top of the framework, screw the steak to the framework using 50mm screws provided. 
  7. Using a spirit level ensuring the base remains level, hit the base level and drive the remaining steaks into the ground in each corner of the base and attach to the framing.
  8. To complete your shed base check that it is completely level with the spirit level and secure to the surrounding ground so doesn’t go out of square or level when the shed goes on. 

 

How to build a garden shed paving slab base?

Number of people installing: 2 

Approx time to produce (if an 8×6): 3 hours 

Tools required: 90 degree builders square, builders string, wooden stakes to tie string around, fork, shovel, spade, spirit level, rake, lump hammer, tape measure, hand brush, trowel, gloves.

Materials required: aggregate / hardcore (10mm to dust), sand and cement mix, paving slabs

  1. Ensure gloves are worn plus any other personal protection you feel is required and complete your own risk assessment of the task for health and safety reasons before starting. 
  2. Mark out the area with builderstring lines in the desired position of your base and use wooden stakes to tie the string to the ground. Use a 90 degree builders square to ensure the base is not out of square. Alternatively measure the base from corner to corner and check that both measurements are equal.
  3. Work out how many flags are required for your shed base. It may be that your base will need to be a little larger than the shed floor if you plan on using full slabs. If not, you may need to cut the flags down (or spread them out a little bit).
  4. Inside the designated area of builder’s string use the fork and shovel to start digging out the grass to a depth of approximately 100mm. This leaves is 30mm for the paving slabs, 20mm for dry mix of sand and cement and 50mm base of the aggregate.
  5. Start with the 50mm of aggregate / hardcore (10mm to dust) and spread out with a rake. Using a plank of wood the width of the base you can pack the aggregate down making it as flat as possible and check it’s level using a spirit level. Use a lump hammer to help pack it down by hammering on top of the plank of wood which is resting on the aggregate.
  6. This is a good time to check / adjust the height of the builder’s lines to the height of the finished flags. This should be 50mm above the aggregate. Check it is flat and square using a spirit level.
  7. Now we add in the sand and cement mix. This is a mix of 9 part sharp sand to 1 part cement which you can mix using the spade. Spread across the base with a rake.
  8. You can now start adding on the paving slabs. They might need a gentle tap with the lump hammer to make sure they are flat – but ensure you don’t hammer too hard which could break the slabs.
  9. Keep using a spirit level to ensure they are flat.
  10. You now need to fill the joints between the slabs in with 5 parts sharp sand to 1 part cement. You can do this simply by using a hand brush and then push down into the joint with a trowel.
  11. Finish by sweeping off any remaining sand cement mix. 

 

How to build a garden shed concrete base?

Number of people installing: 2 

Approx time to produce (if an 8×6): 5 hours 

Tools required: 90 degree builders square, builders string, wooden stakes to tie string around, fork, shovel, spade, spirit level, rake, lump hammer, tape measure, hand brush, trowel, gloves.

 Materials required: aggregate / hardcore (10mm to dust), sand and cement mix, paving slabs 

  1. Ensure gloves are worn plus any other personal protection you feel is required and complete your own risk assessment of the task for health and safety reasons before starting.
  2. Mark out the area with builder’s string lines in the desired position of your base and use wooden stakes to tie the string to the ground. Use a 90 degree builder’s square to ensure the base is not out of square. Alternatively measure the base from corner to corner and check that both measurements are equal.
  3. Inside the designated area of builder’s string use the fork and shovel to start digging out the grass to a depth of approximately 150mm. 
  4. Start with the 75mm of aggregate / hardcore (10mm to dust) and spread out with a rake. Using a plank of wood the width of the base you can pack the aggregate down making it as flat as possible and check it’s level using a spirit level. Use a lump hammer to help pack it down by hammering on top of the plank of wood which is resting on the aggregate.
  5. Remove the builder’s string and wooden steaks.
  6. Add lengths of timber / timber rails around the perimeter of the base. Use a tape measure, spirit level, and 90 degree builder’s square to ensure the base with shuttering is square and level.
  7. Then the 75mm of concrete can go in which is produced with bags of dry mixed concrete and small amounts of water at a time. Please ensure the concrete is not too wet or the concrete will not set properly.
  8. Spread the concrete around the shuttering as evenly as possible ensuring concrete is pushed into corners and edges. Keep filling in the shuttering with concrete until it’s at the top of the framework and smooth it out using a wooden plank of timber. 
  9. Once the concrete is dry you can install your garden building. 

 

After you have got a garden shed base

Once the base is completed, you need a shed to sit on it. To view our range of sheds please click this link below:

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