Plastic Shed Base Foundation

Are you thinking of getting a plastic shed for your backyard? That’s a great idea! Plastic sheds are durable, long-lasting, and require minimal maintenance. However, before you rush into purchasing one, there’s one thing you need to keep in mind – the foundation.

Plastic Shed Base Foundation
Oakland Shed Laid on Wood Decking

The #1 priority when it comes to a plastic shed base foundation is to prepare a solid level substructure for the shed to stand on. Furthermore, ensure it’s raised slightly above the ground’s floodplain level to prevent the shed from being submerged in water during heavy rainfall. Trust me, you don’t want to deal with a flooded shed!

There are a few different options for the foundation. You can use wood decking, paving slabs, concrete, or asphalt to provide a solid substructure. Elevated slightly above the ground will ensure efficient drainage while a level base makes sure that your shed stands perpendicular to the ground.

No matter what type of shed you choose – resin, metal, or wood – it’s crucial that it’s laid above the floodplain level. Sheds are not waterproof unless they are sealed, which is rarely the case. Even if your plastic shed has a built-in floor, there may be faint gaps within the ‘snap into place’ mechanism that could leak rainwater.

Best not to skip the foundation rule

Unfortunately, many sales sites fail to mention the importance of preparing the correct foundations. This is a major oversight and it should be headlining all manufacturer’s guidelines. If you don’t prepare the correct foundation, you’ll end up with a lot of frustrations down the line.

So, what’s the solution? It’s simple – prepare a solid level foundation for your resin shed. This one-step process eliminates assembly headaches and future issues by ensuring your shed stands correctly.

Best not to skip the foundation rule; it may seem like a small detail, but it’s crucial for the longevity and functionality of your shed. Trust me, you won’t regret taking the time to do it right!

Plastic Shed Base Foundation
Plastic Shed Base Foundation

A level base is super important for an easy assembly process.

First off, plastic sheds are made with resin sheets that need to be aligned just right with each other and the metal framework. This can be a real pain if your base isn’t level. So save yourself the frustration and make sure you start from a level foundation before you start putting everything together.

But it’s not just about ease of assembly – having a level base also ensures that your shed doors will open and close properly. Nobody wants wonky doors that stick or don’t quite close all the way. Trust me, I’ve been there.

And if you thought that was bad, an unbalanced foundation can even cause your shed to lean to one side. Yikes! That’s why it’s so important to make sure your shed stands at right angles to the base. This will distribute the weight of the roof evenly across all sides and prevent any leaning or sagging.

Wood Foundation

The reasons for a solid floor

Quality plastic sheds are the way to go! They come with an integrated floor that is tough enough to handle heavy-duty storage. But, here’s the catch – you need to make sure your foundations are solid so that the floor endures the pressures of demanding storage, such as rolling in a heavy-duty lawnmower.

You have the choice of wood decking, asphalt, concrete or paving slabs.

Now, let’s talk about wind resistance and stability. It’s super important to anchor your plastic shed down onto a solid foundation so that it withstands strong winds and keeps everything inside safe and secure. Just keep in mind that anchor screws aren’t included, so you’ll need to choose the right type depending on your foundation material.

So there you have it, folks! Make sure your base is level and you’ll be well on your way to a fast, efficient assembly process with perfectly aligned doors and a sturdy, straight shed that’s anchored down to resist the storms. Happy building!

Factor 8 x 8 Situated on Solid Level Foundations
Factor 8 x 8 Situated on Solid Level Asphalt Foundations

Shed Foundation Construction

There are various ways to install a foundation for your shed. You can find a bunch of cool ideas and how-tos on YouTube. All you’ve got to do is pick the method that works best for your DIY skills, the size of your shed, and where you want to put it.

If you’re not up for a big job, getting a concrete foundation installed by a pro might be the way to go, especially if you’re looking for some extra stability for a super-sized shed. That could be a good option.

For those of us who are less experienced, you can always lay paving slabs or make a wooden frame topped off with timber decking boards, or something like that. It’s totally doable!

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 leftovers fit our dimensions.

We purchased pressure-treated timber and made a framework slightly larger than the area of the shed’s base, 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, then secured 8 legs to the corners and centres measuring about a foot long and then proceeded with the ground location.

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

We dug 6 holes for the legs to stand in, then levelled the framework slightly above ground level by placing gravel in the holes until all legs were firmly grounded. We’d accomplished a perfectly levelled frame.

Make sure Foundations are Perfectly Level
Make sure Foundations are Perfectly Level

Easy Assembly, Lasting Results: A Hassle-Free Guide to Building a Sturdy Shed

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 laid a levelled surface of gravel across the entire ground membrane underneath the frame. After that, we secured decking boards 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 be sure rainfall drains away, increasing the wood’s longevity against decay.

Assembly delivered quite a straightforward job for novice DIYers like us, much easier than mixing and laying concrete. An excellent way for an average-sized resin shed, and we’re 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; building from a level base ensures the panels align correctly and at ease, leading our assembly to a fast efficient construction.

After the shed’s construction, we purchased some wood anchor screws and wide washers to make certain the base of the shed had a secure fixing to the foundations. Job done; we’ve increased its overall stability and provided defence against the gales and adverse weather.

Shed Base Foundation Kits

If you’re in the UK and looking to build a shed, I’ve got some great news for you. Shed-base foundation kits are now available for purchase (Here’s one example, if you’re interested). These kits are perfect for an average shed foundation; they come in various sizes to fit your shed-base dimensions.

The kits themselves are pretty nifty. They contain wooden legs that are secured to the corners and centre positions, just like the framework we created. To position them, all you need to do is dig some holes at the leg positions and level them out by placing grit or pebbles underneath the legs in the ground holes. Make sure the base is elevated slightly above ground level for optimal results.

Once everything is level, it’s time to fill those holes with concrete to create a solid foundation. After that, top it off with some pressure-treated timber boards and you’re ready to start building your shed. It’s pretty straightforward.

Video – Timber Base Foundation

This video shows a very similar concreting process to which we performed 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 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.

Video – Shed Foundations using Paving Slabs

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


Video – 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 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

Hope these ideas help – take a look around this website and check out the Quality Plastic Sheds if the low-maintenance route captivates your interest.

Plastic Shed Base Foundation
Plastic Shed Base Foundation

Disclaimer: I do my best to provide accurate information, however, I may make mistakes. Please check the Seller’s description, read the comments and ask the Seller any questions you may have.



  1. Wil Laurent

    Hello. I live in Southern California and am building a wood base for a small (4’x6’) plastic shed. The base will be 6” to 8” off of the ground. Will I need a vapor barrier? If yes, is the barrier installed beneath the deck or between the deck and the shed floor? Thx for your help.

    • Hi, Wil, a breathable membrane helps prevent any water penetration if you are going to insulate a shed, however, it’s not usually recommended if you’re not insulating. We didn’t install a vapor barrier underneath our plastic shed, and it’s stood the test of time for years – just make sure rainwater can drain away quickly from the foundation.
      Hope this helps, thanks for stopping by,

  2. Steve

    Hi Simon,
    Great article on plastic sheds, wish I found you earlier!! I’ve recently put up a lifetime 10×8 shed on a raised wooden base, which was done by professionals not myself but I am getting rain water in between the gaps in the plastic floor,I put in drainage holes but maybe not enough or big enough, am I going to need to take down the shed to put in more holes or could a drill through the floor and cover with a waterproof flooring?
    Many thanks for any advice.

    • Hi, Steve, it sounds like you need to drill some more holes to drain the rainwater away.
      Is there any way you can empty the shed, remove the anchor bolts and move it across the wood foundation, supported by a few people, so that you can drill more holes underneath where the shed stands; rather than dismantle the shed. Obviously this depends on the size-weight of your shed.
      I wouldn’t opt to drill holes through the shed floor. I would drill holes at any spots where the water puddles – you need to create immediate drainage.
      I hope you manage to get things sorted – good luck,

      • Steve

        Thank you for taking the time to reply Simon, unfortunately I cannot move the shed enough as it is on a raised wooden base that is only slightly bigger then the shed, I understand it is not ideal drilling through the floor but do you think that would work if I managed to cover up the holes in the floor only?
        I can only assume the water is leaking in between floor and the wooden base,I have tried to use a sealant but that hasn’t seemed to work, is it inevitable that water will get in between the base and floor due to the design of a plastic shed or can this be stopped?
        Once again thank you for any advice, can’t seem to get much help on plastic sheds.

        • Hi, Steve, it sounds like drilling through the floor seems to be your only option – try and think of some way you can seal the hole (in just the floor) after drilling through. The main thing is creating a way for rain water to immediately drain away. I know it’s not ideal but I personally would opt for that way than dismantling the shed.
          Good luck – I hope you manage to get things sorted.

          • Steve

            I’m going to drill the holes through the floor, cover with a heavy duty waterproof duck tape and then put down floor mats.
            Hopefully that will solve the issue. Once again thank you so much Simon for taking the time to reply, your advice had been much appreciated. All the best.

          • That sounds like a good plan, Steve – hope you manage to solve the issue and drain the rainwater away.
            Wishing you all the best.

  3. Kerry

    Hi Simon
    We have just got 8×8 resin shed. Concrete base. That part is all good. However after a week we got really high winds. To our horror the roof started to lift off. Woth quick action nothing cracked or broken. How do we prevent this happening in the future?
    Regards, Kerry

    • Hi, Kerry, that’s not good.
      I would go to the manufacturer’s website and click on their Contact Page and ask them how you could prevent this from happening again in the future. Most shed companies are very helpful and respond quickly.
      Hope this helps and you get a quick reply to get things sorted – good luck,

  4. A geocell type of foundation is a versatile panel system that you install by laying on the ground and filling with aggregate or other material. This affordable product has the strength of concrete without ongoing maintenance costs. Our customers love geocell as a durable and affordable option for their backyard shed projects.

    • Thanks for sharing your info about the geocell type of foundation.

  5. 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,

  6. 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.

  7. 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.

  8. 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.

  9. 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,

  10. 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,

  11. 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,

  12. 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,

  13. 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.

  14. 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,


  15. 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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