Jacks guide: How to build a shed base.

by Jack Gardener on June 21, 2010 · 3 comments

in Sheds

Rowlinson Wooden Workshop 9x15

Rowlinson Wooden Workshop 9x15

All garden sheds require a strong and sturdy base. If you are planning to build a new shed in your garden you must ensure that you have a level sound base for it to go on. Always remember that your new shed requires a level and dry foundation, if the base area is not level the screw hooks that connect the wall panels will not line up.

Two types of suitable shed base:

  1. Concrete shed base.
  2. Paving slab shed base.

With both methods please ensure that you create a 2 inch lip around the base of your garden shed. To calculate the exact size of the foundation base you need simply add 4 inches to the overall base dimensions and this will give you the additional 2 inches on each side.

Concrete Base Method

When constructing a concrete shed base you will require the following equipment:
Pegs and String
Building Sand
Cement
Timber for base formwork
Shovel
Sweeping Brush
Rake
Saw

Use the pegs and string to mark out where you want the shed base to go and remember to include the additional 2 inch lip on each side using the method above. Once you have marked out the space measure the diagonals to ensure the area is square.

Now it’s time to get digging! A concrete shed base needs 3 inches of compact hardcore underneath the layer of concrete which also must be 3 inches. You can choose whether you want your shed base to be level with the ground or raised above it. IF you want your new garden shed to be level with the ground then dig and remove 6 inches of top soil which will allow plenty of room for the layer of hardcore and the layer of concrete. Then level the area with a rake and remove the pegs.

Ok the next task is now to set up the levelled formwork. For this you must cut and fit your timber into the shape of the base so that the concrete will be contained. Make sure that you check that the formwork is 100% level and also that it is square by checking the diagonals.

Spread a layer of compacted hardcore and on top of it a layer of sand.

Create the concrete mix using one part cement and 5 parts ballast, adding small amounts of water each time so that the concrete never gets too sloppy and always remains quite dry.

Spread the concrete and level off using a large piece of wood.

If rain has been forecast cover the concrete with polythene for 24 hours if not dimply cover the base with damp sacks that have been sprinkled with water and keep then over the shed base for 24 hours. This will stop the base concrete from shrinking or getting cracks.

Slab Base Method

When constructing a slab shed base you will require the following equipment:
Pegs and String
Building Sand
Paving slabs that are flat and level
Cement
Shovel
Sweeping Brush
Rake
Tape Measure
Spirit Level

Use the pegs and string to mark out where you want the shed base to go and remember to include the additional 2 inch lip on each side using the method above. Once you have marked out the space measure the diagonals to ensure the area is square.

Dig down 2.5 inches, this is the depth required to accommodate the shed base. Once completed remove the pegs.

Next mix together one part cement and 8 parts building sand and cement mix and spread this evenly out making sure that the mix is approximately 4cm in depth. Level the mixture so that the base is level.

Now you can lay the paving slabs. Start from one corner and work outwards laying each slab down and then gently tapping it in the centre with a rubber mallet. Use a spirit level to check that all the slabs are square and level so that you have a solid shed base.

Once all the paving slabs have been laid and the level checked, brush off any excess sand or cement and your work is done!

For a fantastic range of wooden sheds, metal sheds and plastic sheds visit Jacks Garden Store where not only will you find great prices but also free delivery on our entire garden sheds range.

Good Luck

Gardener Jack!

About The Author

Jack Gardener has been gardening all his life, and is passionate about passing on his experience to the next generation of gardeners.

{ 2 comments… read them below or add one }

Brian January 14, 2011 at 6:58 pm

I have a serious condensation problem in a large wooden shed used to hold yoga classes (max of 7 persons breathing). The shed is off the ground, on concrete blocks. The low ceiling and the walls are all tongue and groove, which have been varnished. The floor is laminated. There are three windows and a door. The shed is approx 27ft x 11ft. During classes, the floor gets saturated with moisture as do the windows, walls and ceilings. I know the breathing and heat emanating from the people plays a big part in this, but I wonder how can I reduce or solve this problem? Thanks.

Reply

Jack January 31, 2011 at 4:27 pm

You cannot solve the problem but using electric fans and improving the ventilation in your shed will help to reduce this problem. Try keeping the windows or doors open where possible to allow air to circulate and moisture to escape.

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