Plastic Shed Base Foundation

The #1 priority regarding a plastic shed base foundation is to prepare a solid level substructure for the shed to stand on whilst raised slightly above the grounds floodplain level to avoid the shed being sat in a flood is highly beneficial.

Plastic Shed Base Foundation

Oakland Shed Laid on Wood Decking

Typical foundations for a resin shed relate to either a decked wood frame, paving slabs or concrete providing the solid substructure, elevated slightly above the ground to ensure efficient drainage and laid perfectly level to accomplish a flawless shed construction.

Whether resin, metal or wood sheds are your preferred choice, it’s imperative they are laid above a floodplain level. Sheds are not waterproof unless they are sealed which is rarely the case. Quality plastic sheds do have a built-in floor however due to their interlocking assembly procedure faint gaps within their ‘snap into place’ mechanism will leak rainwater therefore construction above a floodplain level is essential.

Unfortunately very few sales sites mention the importance of preparing the correct foundations, a stipulation headlining all manufacturers instructions leaving purchaser to find out after delivery, leading many to side-step this rule due to time restraints however failing to adhere can present frustrations.

Solid level foundations are imperative for any plastic shed construction. This one-step process regarding preparing the correct base eliminates assembly headaches and future issues in one fell swoop by ensuring a superlative shed stance.

Plastic Shed Base Foundation

Plastic Shed Base Foundation

  • Plastic sheds are manufactured with resin sheets, each sheet requires a plumb alignment with the next panel and their fixing holes to line-up with the holes in the metal framework prior to securing with screws. A perfectly level base escapes frustrations by delivering easy alignment and aids accomplishing a fast efficient assembly procedure.
  • The vertical alignment of the doors can present a nightmare from an irregular base. On the contrary, level footings enable achieving a plumb door alignment ensuring a true opening swing and the correct closure is delivered.
  • Unbalanced foundations can generate leaning pressures to one side of the shed. Level foundations eliminate stresses by ensuring the shed stands perpendicular to the base, imperative for the roof weight to apply equal force on all sides of the shed.

Wood Foundation

  • Quality plastic sheds are all inclusive of an integrated floor. Their floors vary in thickness and are purposely toughened to cope with the stresses heavy duty storage endures however they all require a solid flat base in order to survive the pressures and provide longevity for demanding use.
  • It’s important to anchor plastic sheds down onto the solid foundations to increase wind resistance levels and stability regarding their overall construction. Anchor screws are not included, their type is dependant on the foundation material laid below.
Factor 8 x 8 Situated on Solid Level Foundations

Factor 8 x 8 Situated on Solid Level Foundations

Shed Foundation Construction

There’s a plethora of different ways to install foundations, YouTube is full of ideas and demonstrations, it’s just a matter of choosing a method that suits your DIY skills, shed serviceability and location.

Many people prefer concrete foundations to be professionally installed due to their workload and machinery required but this maybe a preferred option if you require an extremely large shed for more stability.

Levelling paving slabs or making a wooden framework and topping off with either decking boards or OSB board etc can be accomplished by a more novice DIYer.

Our Decision – Wood Foundations

We decided on wooden decking for our resin shed foundations, simply because some friends had a surplus of decking left over after completing their patio, the left-overs fit our dimensions.

Purchasing pressure treated timber we made a framework slightly larger than the shed’s base expanse, making sure it was perfectly square by measuring across both corner-to-corners. Equal measurements across both corners deliver a perfect rectangle/square.

Pressure Treated Timber Frame

Pressure Treated Timber Frame

We fit a few spurs of timber across the widths in equal measurements to enable supporting the decking, secured 6 legs to the corners and centres measuring about a foot long and then proceeded with the ground location.

After choosing the required spot enabling movement around all sides for shed assembly purposes we levelled the ground with a rake and covered the base expanse with a membrane to prevent weeds growing.

We dug 6 holes for the legs to stand in and levelled the framework slightly above ground level by placing gravel in the holes until all legs were firmly grounded whist accomplishing a perfectly levelled frame.

Make sure Foundations are Perfectly Level

Make sure Foundations are Perfectly Level

We mixed Postcrete and water in each of the holes just like you do for installing garden fence posts, this sets in 20 minutes although we left it overnight to be certain.

We then proceeded to place a levelled surface of gravel across the entire ground-membrane underneath the frame to maintain its position followed by securing decking across the framework. A great tip we picked up was to drill a few holes into the deck-boards underneath where the shed sits to allow for drainage increasing the wood’s longevity against decay.

Assembly delivered quite a straightforward job for novice DIYers like Tracy and myself, much easier than mixing and laying concrete. A great way for an average sized resin shed, very pleased with the outcome.

We secured decking boards across the framework top

We secured decking boards across the framework top

Assembling the shed went like a dream, it’s all down to laying a perfectly levelled base ensuring the panels align correctly and at ease, leading our assembly on to a fast efficient construction.

After the shed’s construction we purchased some wood anchor screws and wide washers to ensure a good fixing between the sheds base and foundations, increasing overall stability, thus providing sustained defence against adverse weather.

Storage Shed Foundation Ideas

You can purchase shed-base foundation kits ( This is an affiliate link. Read the Affiliate Marketing Disclosureover in the UK nowadays to fit almost any shed foundation plans, consisting of a similar structure to our framework, available in various sizes to suit different shed base dimensions.

These specific kits contain wooden legs, secured to the corners and centre positions just like we created. Positioning is achieved by digging holes at the leg positions and levelled by placing grit or pebbles underneath the legs in the holes making sure the base is elevated slightly above ground level. Once perfectly level it’s time to fill the holes with concrete to produce a solid foundation followed by topping off with decking or OSB boards prior to constructing the shed.

Timber Framed Foundation

This video shows a very similar concreting process to which we performed yet with metal spikes rather than wood legs, notice the ground membrane under the decking, this prevents weeds from growing underneath yet allows for drainage.

Video – Shed Foundation Kits

Other shed foundation kits contain a similar framed structure to our method however instead of wooden legs to which we concreted into the ground these kits come with metal ground spikes which are secured to the frame and hammered down into the ground until a levelled sub-frame is produced.

Shed Foundations using Paving Slabs

Here’s a great B&Q video regarding how to level paving slabs into the ground to accomplish creating the perfect resin shed foundation. Top tips here:


How to lay a level concrete foundation

There’s a lot more involved with mixing and laying concrete, it requires more advanced DIY skills, hefty bags of concrete and a concrete mixer yet is the best solution for an extremely large shed construction in order to further increase stability. Many people ask a local builder to lay concrete foundations.


More ‘Build A Shed Foundation’ Ideas

Tiger sheds have an excellent post divided into 3 sections, explaining the process of laying concrete foundations, paving slabs and a timber bearers method which is worth inspecting.

B&Q’s dedicated foundation page describes the various ways and methods shed bases are professionally laid down for a garden shed.

Suncast Everett located on Solid Level Foundations

Suncast Everett located on Solid Level Foundations

Explore the various Quality Plastic Sheds reviewed on this website – Sizes, designs and budgets to suit a whole spectrum of low maintenance outdoor storage solutions.

Plastic Shed Base Foundation

Plastic Shed Base Foundation

Thanks for reading the various methods of preparing a plastic shed base foundation.

If you have any tips and wish to share, please feel free to drop them in the comment section below.

Thanks again,


Please share these foundation rules with your social friends. Thank you!



  1. Aisling Judge

    Hi Steven,
    What a great post! I’m about to put a Keter Factor 6×6 shed onto a pre-existing gravel foundation on my allotment in Cardiff. It is fairly exposed so I need a heavy base to secure it too. Laying concrete is not an option – would concrete paving slabs just laid (and levelled) on top of the gravel be ok? What would I use to fix the shed to the slabs? They are Marshalls-Richmond-Smooth-Buff-Paving-Slab-450-x-450-x-32-mm, from Wickes

    • Hi, thanks for reading.
      We made a similar foundation and laid paving slabs. We drilled into the paving slabs, inserted raw plugs and secured the base down with screws. I also used wide washers to stop the screws from cutting the resin floor.
      Hope this helps – good luck with your build,

  2. You can build a geocell shed base without fabric material, but our team suggests it. There’s a chance your infill gravel will seep through the soil and leave space in the geocells, creating unstable ground.

  3. Stew C

    Hello Simon,

    First, thanks for being so generous with your time and knowledge. All great information.
    No dates posted on messages so not sure if you are still active with the site but figured I’d take a shot.

    Project Overview:
    I am about to install a Lifetime 8’ X 15’ vinyl shed onto an existing ¾” gravel base which measures 10’ X 16’ and is framed by 4”X4” pressure treated GC lumber. Due to the grade of the property depth of gravel runs from 5” (1” above grade) to 18” (16” above grade) the lumber is excellent condition and the gravel has been leveled and firmly tamped down by machine. Drainage has been provided for in frame however I am in the Northeast and I have some concerns about frost heave in the winter.

    In your opinion, should I build a 2”X4” platform topped with 1” PTGC plywood to place between shed floor and gravel? It doesn’t seem that paving stones would be an economical option.

    Thanks for your time and response.

    • Hi, Stew, thanks for messaging.
      In my opinion, I would build a 2” X 4” platform topped with plywood for the shed to be anchored down to – it would be a more economical option compared to paving stones, alleviate frost concerns, plus a wooden platform makes it a straightforward job to anchor down the shed floor.
      Hope this helps – good luck with your build.

  4. High-density polyethylene (HDPE) geocell panels are tried and true shed bases the Army Corps have used since the 70s. All you need to do is expand them over the subgrade, stake with rebar, infill with base material, and compact. Geocells for sheds are as strong as concrete while retaining perforation (holes) that allow for natural drainage.

    • Thanks for sharing your info about shed bases used by the Army Corps – these sound ideal for all sheds.

  5. DerrickS

    Hi Simon,
    Again there is a lots great information covered. I purchase a 7 x 7 resin shed and wanted to know what should I used for the base (wood or 24 x 24 paving bricks. either case I will need gravel. I am thinking wood will be ok as I will be storing lawn equipment. Yard does get a little flooded at time due to all the rain we get here in Georgia . May have to sit is a little high with a ramp.

    thanks for input.

    • Hi, Derrick, it sounds like a raised wood foundation sat on a level base of crushed gravel would better suit your requirements. Preventing the shed from becoming flooded by providing quick natural drainage through the gravel sounds an ideal solution.
      Wishing you all the best on building your foundations, thanks for leaving your message,

  6. Donna Scurrey

    Hi there I have a concrete foundation in place for a resin shed to be placed on it. Is it necessary to screw the floor of the shed into the concrete? I am planning on putting hook rings in the ground around the shed so I can put straps over the shed to hook in place so the wind does not take it . Please advise. Thank you.

    • Hi, Donna – yes, it’s recommended in the instructions to secure the floor down into the solid foundations.
      Hope this helps – thanks for visiting,

  7. Ray Kreuzer

    Hello I have an 8×10 lifetime shed being delivered I am getting foundation ready. I was going to put a frame of 4×6 with 1/2 in crushed stone down will this work.

    • Hi, Ray, thanks for messaging.
      I prefer solid level foundations for a resin shed for the reason the shed stands perpendicular plus you are able to screw the base of the shed down into the solid foundations, providing a firm grounding.
      If your 4×6 framework is heavy and it stands level, you should be okay
      Hope this helps,

  8. Andy

    I’m thinking of buying a Lifetime resin shed 8×12.5ft. For the foundation I was thinking of a gravel pad. I see in one of your images you have a wooden foundation over top of the crushed gravel. How does this work? How do I anchor the wooden foundation to the gravel? Do I even need the gravel or can I just put the wooden foundation straight on the ground?

    • Hi, Andy, Wood foundations are okay for small plastic sheds but an 8 x 12.5 ft shed would be better anchored down to a solid base such as concrete, tarmac, or paving slabs in my view due to the sheer size.
      A shed this size requires solid, flat, and level foundations to ensure the shed stands perpendicular and to enable firm anchorage.
      Hope this helps,

  9. Lawrence Rose

    Hello Simon

    Thank for all the interesting content!

    I’m planning to use a Keter 8’ x 6’ plastic shed (it has its own plastic floor) and site it on a plastic (EcoBase) base. The base will be infilled with gravel.

    The top of the base will be above ground level, so there should be no risk of flooding.

    Would you recommend using battens under the shed or should it be OK to just place the shed directly onto the base?

    Thanks for any advice you can provide, and keep up the good work!


    • Hi Lawrence, I would use battens on the base to make sure the shed sits on a solid flat levelled surface, then anchor the base into the wood.
      Hope this helps.

  10. AlexRockin

    Hi Simon,

    This is a great article and very detail information. I live in Florida and in need of a new shed. We currently have a wood base and it’s rotting due to the weather here.

    When we are ready to get a new shed we will definitely have to put down a concrete or paving slabs foundation.

    It’s great to know the other options instead of wood. I am not sure why someone in Florida would do that, but that is for another time LOL 🙂

    Alex & Ann

    • Simon

      Hi Alex & Ann,

      Thanks for dropping by and reading about the various methods and materials a plastic shed base foundation can be prepared with.

      Yeah, rotting issues, that’s the major issue regarding wood. We did use decking simply because some friends had a surplus left over after building their patio, all we really required was a levelled framework preparing however we took a great tip on board and drilled a load of holes beneath where the shed sits to ensure water runs straight through rather than puddle, this does increase the wood’s longevity to decay.

      Concrete or paving slabs are ideal, there’s two great videos here on how to prepare them both level as this is a resin shed’s requirement. If you opt for extra large sheds where heavy duty equipment is gong to be rolling in and out on a regular basis, I would sway towards concrete to maintain a levelled position long term.

      You in Florida have very similar rainfall levels to us here in the UK however you get plenty of summer sunshine and red hot weather in among, unfortunately this is quite rare over in the UK – ha!

      Thanks Alex & Ann. Good luck building your next foundations,


  11. HappyB

    Thanks Simon. This is really helpful. I am buying a resin shed for my son (belated birthday present!!,)who has a “base” already in place and I was wondering how to ensure the shed remained stable and did not blow away. The base is concrete and probably supported a shed from a previous occupier.
    If it proves to be level, we should only have to solve the problem of fastening it.
    If, as I suspect, the base is not level, do you think it is better to skim it with concrete to level it or build a timber base?
    It is pretty sheltered with walls on 2 sides and would face a house wall about 10 feet away.
    Maybe a Keter shed with integrated base would be a good idea. Then I would worry about the concrete being uneven below it.
    Thanks for a detailed coverage of all these sheds. It has been extremely helpful.

    • Simon

      Hi HappyB,

      Thanks for visiting and reading about preparing a plastic shed base foundation.

      For any resin shed, the priority is to have a solid level flat base, sounds like you’re nearly there however I would skim the surface completely level and flat prior to assembly. Resin shed floors are all purposely toughened to cope with heavy duty storage pressure IF they are mounted on the correct foundations, their construction certainly requires it.

      Failing that, dependant on one’s DIY skills if levelling concrete is not your bag, level a timber frame on top, that would be fine also.

      Hope this helps and thanks again for getting in touch,


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