How to build 3m x 1.51m wooden base for storage shed?

[stewbiedoooo]

I’m purchasing a 3 x 1.51m shed 

I need to build a base for it but Im unable to have a permanent foundation 

have decided to build a wooden foundation 

I need to know what wood to buy that will hold up to the elements 

what thickness wooden to suit the size of shed

how far I should have the spacing to then add flooring

And any other suggestions or tips would be greatly appreciated 

thanking you in advance 

nick 

[Jewelleryrescue]

Hi @stewbiedoooo 

Basically your building a mini deck of set dimensions.  So to advance your planning look up deck projects and best how toos. For starters  use H4 treated pine for the ground timber  as a guide.  

Others will be able to reference you too deck building resources soon

[JacobZ]

Hi Nick (@stewbiedoooo),

A warm welcome to the Bunnings Workshop community and thank you for your question.

It should be noted that most shed manufacturers will not offer a warranty on a shed that is not installed on a concrete base. You can do it, but it is unlikely it will be covered by a warranty. 

As @Jewelleryrescue has already mentioned, you are essentially building a timber deck, so the principles of deck building apply.

You might like to check out the following articles for some guidance.

• How to build a low-level deck
   
• How To Build A Deck
   
• How to understand deck components
   
• How to understand deck span tables.

You can look at the Absco Sheds 1.52 x 0.78m Timber Flooring Kit as an example of what would be required.

If it is in direct contact with the ground, you should use H4-treated timber. If it is elevated, you can use H3-treated timber.

Your joists should be spaced 450mm apart to support your flooring, which should be H3-treated to resist weathering.

A frame made from treated pine sleepers seems like a good option.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob

[MitchellMc]

Hi @stewbiedoooo,

I thought I'd just add that nothing beats a concrete base for a shed. It provides a secure, immovable foundation that ensures your shed stays in place, regardless of the weather or ground conditions. Concrete bases require no maintenance and are incredibly durable, lasting for many years. Unlike other options, you won’t have to worry about shifting or rotting, making it the most reliable and long-lasting choice for a solid foundation.

Here's a helpful step-by-step guide: How to pour a concrete slab.

Please let me know if you have any questions.

Mitchell