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Innovative Techniques: Creating a Solid Foundation for Your Garden Workshop

Building a solid foundation for your garden workshop ensures it remains stable, level and damp-free. This comprehensive guide explains how to do it in detail.

The Ultimate Guide To Building A Base For A Garden Workshop

Shows image of garden building

Wooden workshops are a must-have addition to any traditional British garden. These sanctuaries allow you to enjoy the seasons in all its splendour while protecting from the sun, wind, and rain.

However, if you want your garden workshop to last, you must understand how to lay the foundation. It may decompose from the ground up, tip over, or fall victim to the wind if you don’t.

Fortunately, you won’t have to figure out how to build a garden workshop foundation independently. This guide is here to help. It covers the various types of bases for garden buildings, how to create one, who to hire for base construction, and how to repair and maintain your installation. Everything you need is in one place.

Why Do Garden Workshops Need Bases

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When constructing a garden structure, bases are essential for stability and durability. Without a solid foundation, the structure is prone to shifting and settling, which can have long-term consequences.

Bases provide a flat platform for the building to sit on, evenly distributing weight and reducing the possibility of structural issues. Bases also help to elevate the structure off the ground, reducing moisture exposure and preventing rot and deterioration.

Overall, investing in a strong foundation is critical for the stability and longevity of a building. They still need a solid foundation that will allow them to function indefinitely. Without it, they will not survive.


The primary goal of building bases is to ensure structural longevity. These constructions protect moisture, preventing ground moisture from permeating the garden workshop’s floor and walls.

Keeping the structure dry reduces the risk of rot, mould, and structural distortion and makes it easier to maintain.

Level Ground

Bases also provide level ground for all manner of buildings. Professionals build these to create a flat surface that allows the garden workshop to sit upright.

Without bases, garden workshops would be completely reliant on the flatness of the ground beneath them. The ground must be precisely level throughout the duration of the construction to keep it straight and accurate.

Bases keep one side of the workshop from sitting lower or at an angle than the others. This holds the structure upright, much like traditional home foundations.


Finally, wooden workshop bases offer stability. Hard materials, such as concrete or pavement slabs, keep the structure from shaking as people walk inside.

Bases for Garden Buildings

Garden structures require a variety of bases to remain level and stable. Your priorities, the climate, and other factors will all influence your decision.

The three basic base types available are as follows. We investigate what they are and the advantages and disadvantages of each. You should have collected enough data to determine which option is best for your project.

Concrete foundation

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Concrete foundations are solid slabs embedded in the ground (often during excavation). Installers use special tools to ensure the material sets smoothly, forming a strong foundation for the garden workshop.


  • Extreme stability and durability. Concrete is a highly durable material ideal for outdoor applications in exposed areas. It works especially well for heavier outbuildings like garden workshops.
  • Long life. Most concrete bases last for decades. (Some property owners continue to use concrete platforms built during WWII). Once installed, it often outlasts the structure it supports.
  • Needs minimal maintenance. Concrete bases do not require treatment. Once in place, maintenance is beneficial but not necessary.


  • Drainage concerns. Concrete slabs can collect moisture beneath them, which can seep into the material over time due to tiny porous holes.
  • More difficult to install. Professionals do not recommend DIY concrete base installation. Excavating, soil preparation, curing, and levelling are only a few of the many intricate stages required in construction.
  • Furthermore, correcting flaws is challenging, requiring breaking up and reinstalling the concrete.
  • Costly. Concrete bases are more expensive than other options (because of material and workmanship costs).
  • The installation process is time-consuming. garden workshop owners must wait for the concrete to be completely set before erecting the building on top. This procedure can take days or weeks, depending on the product.

Paving Slab Base

Shows image of paving slab base

Paving slab bases are simpler, consisting of slabs put over crushed materials such as gravel or with no sub-base (not advised). These provide many homes with a desirable look without the sturdiness of concrete.


  • Simple to alter. Installers do not have to lay paving slab bases properly the first time. DIYers and pros can experiment with each stone and the aggregate beneath it until everything comes together.
  • Built-in adjustment. Owners can move pavement slabs over time in response to ground density and subsidence. Sub-bases can be easily re-levelled for paving relaying.
  • Quicker installation. Aggregate foundations and paving slabs do not require any specific tools or equipment. Groundwork is still necessary, but it is less involved than concrete.


  • Less reliable. Paving slabs may slide and rock when the sub-base shifts, making any garden constructions less sturdy.
  • Higher maintenance. Concrete bases remain consistent throughout their lifespan, whereas paving slabs might migrate or change height. Depending on the surrounding landscape, owners may need to re-level paving slab bases regularly, which increases maintenance requirements.
  • Sub-base drainage problems. Paving slab aggregates may prevent water from draining adequately into the surrounding soil (particularly as they age). Sub-bases may require replacement (which entails raising the slabs, refilling the excavated area, and replacing them).

Timber sub-frame base

Shows image of timber subframe base

Timber sub-frame bases are constructed using treated wooden beams on concrete pads or foundations. The structure sits on top of these, lowering the chance of moisture damage.

Timber sub-frame bases were more popular in the past because the material was widely available. However, it necessitates the construction of a concrete supporting structure.


  • Suitable for lighter soils. Wood bases weigh less, making them better suited to softer soils.
  • It is cost-effective. garden workshop owners can add wooden beams to existing concrete work, significantly reducing installation expenses.
  • Easy to install. Timber subframes do not require curing or drying time.


  • Concrete must, ideally, be pre-installed. Most timber subframes require pre-installed concrete pads or pillars to function properly. Others require bricks to form a barrier with the underlying soil.
  • Poor durability. Timber is less durable than concrete because it is susceptible to moisture, decay, and burrowing insects.
  • High maintenance needs. Timber sub-bases require continual preservative treatment. Accessing individual beams beneath a summer home to perform this maintenance can be difficult.
  • Limited weight capacity. Wood beams are weaker than concrete and stone pavings, limiting their ability to support big garden structures above them.

1st Choice’s ‘No Concrete’ Answer with Timber Subframe Bases

Standard Timber Subframe Base
This is the ideal solution for garden sheds and workshops when the intended site is relatively level or when a base is needed to sit atop and level an existing concrete base; it is also very popular when access to the property is restricted or when people wish to avoid the disruption of concrete base construction.

A sturdy frame is constructed using 100mm x 47mm structurally graded C24 spruce, subjected to an enhanced pressure treatment process to improve its life.

To increase rigidity, cross members are placed at centres between 35cm and 42cm (14” and 16 1/2”) and noggins when the base’s width is greater than 1.5m (5’). The frame is levelled and supported on indestructible recycled plastic ground posts manually driven into the ground.

When the timber subframe is sat atop a concrete base, these plastic posts are not required, and chunky timber feet are used instead when levelling is required.

Heavy Duty Timber Subframe Base
Whilst our standard timber subframe bases are ideal for most situations, sometimes something more robust is called upon. This may be because the building is particularly large or heavy, the plan is to store a large amount of weight within the building, or simply because the ground on which the base is situated has more than a minor slope.

Whatever the reason, our installation team will upgrade the standard specification by upgrading the fixings to coach screws, digging out each post and concreting these into the ground and, where necessary, fitting diagonal braces to add rigidity to the joint between the ground post and the rame (when the base is elevated out of the ground). A wise upgrade when ordering a log cabin or other larger building; please ask our sales advisors for guidance if you need more clarification.

You can find more details here.

When deciding on a base for your garden room, consider these advantages and disadvantages. Manufacturers will usually advise you which base type works best with their items.

A Step-by-Step Guide to Creating a Garden Building Base

Some homeowners hire specialists to build garden bases. If you feel brave enough, you can do it yourself.

This method can be challenging to master, so strictly adhere to the directions provided. Deviating from them may endanger your garden workshop (or any other garden structure you place on top).

Site clearing and preparation

The first step is to clear and prepare the place for installation. Getting this right enhances the likelihood of constructing a long-lasting base.

Start by clearing the space. Remove anything that could come in the way of the building. For instance, make sure you eliminate:

  • Grass
  • Weeds.
  • Shrubbery.
  • Rocks
  • Bricks.
  • Garden waste.
  • Compost.

The site should be devoid of anything other than earth. If you want your garden workshop to sit on your lawn, limit how much grass you remove. Taking away too much may endanger your appearance.

After you’ve cleared the area, measure the base’s outline. Marking where it will go reveals its footprint in your garden.

Most DIYers use a combination of string and stakes. You can also mark the area with paint, but let it dry first to avoid destroying the basic materials.

Always use a measuring tape to mark the contour of the base. When picking a footprint, remember to consider the shape of your garden workshop. Most units are square or rectangular, while some are hexagonal or octagonal, making base construction more challenging.

Ground Leveling

The next stage is to level the exposed ground. Making it flat makes it easier to construct the base.

Most terrain is not level, so you must consider the slope. Identifying minor peaks and dips allows you to assess whether you require complete levelling.

You may notice that the land is lumpy but generally level. Other patches have significant slopes and are more challenging to level.

If the site has a steep incline, consider building your building somewhere else. Slope removal necessitates extensive excavation, and new retaining walls may be required.

Earth must be added and removed to level slopes for garden buildings. Unless the slope is steep, ensure the levelled area is the same height as the surrounding region.

Use a shovel or rake to disperse soil across the land for smaller jobs uniformly. Removing soil from specific locations and depositing it in others can result in a more level surface.

Rent machines for more extensive operations. Diggers and tractors can level areas of land using various scoops and attachments.

Ground levelling is a complicated process that might take a long time. Be patient with it. If you aren’t satisfied with the levelling after one day, return to it the following and try again with fresh eyes.

During levelling, make sure the soil stays within your defined border. If possible, avoid removing soil from other locations.

Finally, ensure that the levelling does not harm drainage near the site. Don’t level land that slopes towards an existing building.

When preparing land, observe where the water flows. Check that it flows away from existing structures and into appropriate drainage channels.

Skilled garden-building base installers can level the land to slope slightly in the desired direction. However, you should only do this if you have the ability and motivation to do so.

Weed Membrane Installation

In rare cases, it may be required to lay a weed membrane. Putting it down keeps persistent weeds from penetrating the soil and destroying the subbase.

Do not use ordinary weed membranes. These are more robust and durable to protect your garden building. Use items designed exclusively for garden workshops, then put them over the base area’s edges using the supplied fittings.

Allow the soil to compact.

After you’ve finished levelling, give the soil time to consolidate. Allowing it to squash removes air pockets and increases stability.

Unfortunately, passive soil compaction may take weeks or months. To work faster, professionals employ a variety of compaction instruments. These continually press into the dirt, pounding it in place.

Compaction equipment can rapidly identify differential densities in your soil foundation. If you observe any development, add more soil, rake it over, and continue compacting.

When compacting, be methodical. Begin at one corner and move in lines until you have covered the marked space. Continue continuing until the soil stops moving.

If you don’t have any compaction tools, you can rent them from a nearby builder’s yard or equipment store. Compacting land to an adequate density should take at most a day.

Add the base material.

Once you’ve prepared your garden base, the next step is to add the base materials. Here are the three base materials and how to install them.

The Concrete Base

Concrete preparation is the first step in installing a concrete basis. You can use ready-mix concrete (made in a mixer) or bagged concrete for a modest garden construction.

You’ll also need:

  • A spirit level.
  • Edging boards
  • Crushed rock sub-base
  • Mixing tools
  • Wheelbarrow.
  • Shovel
  • Goggles and gloves

Excavating for concrete bases is only sometimes necessary. As a result, you may need to dig into the dirt.

Most experts recommend digging down 100mm (about 5 inches) if you have moist soil or wish to construct a large building on the base. Once the excavation is finished, you can add the aggregate. It will function as a base drainage system, preventing rising water from causing flooding or other harm.

Formwork may be required in big concrete base projects. Edging boards border the base’s boundaries and keep the concrete in place while it hardens.

After these preparations, it’s time for the concrete. Mix according to the manufacturer’s directions (concrete mixing varies greatly between brands).

Once mixed, pour the concrete fast. Leaving it too long may lead it to set before entering the base.

Pour the concrete into the indicated base area. You will observe it spreading to occupy the available space. (If it is too thick, it will not spread, and you should make a fresh batch).

For big bases, utilise a concrete pump. These move large amounts of material from a truck to the nozzle, avoiding the need for wheelbarrows and other temporary solutions.

After pouring the concrete, level it to make a smooth surface. Most do-it-yourselfers use a screed, which is simple portable equipment. Rake it over to ensure the concrete is level with your edging boards (if you are using them).

The concrete should slope slightly away from nearby buildings to ensure efficient drainage. A perfectly flat surface may cause water pooling or surface runoff in the wrong direction.

The final step is to finish and cure. Concrete needs time to set correctly.

Most products dry in 24 to 48 hours. However, some concretes may take up to 28 days to attain full strength.

While the concrete is curing, some specialists erect buildings on top of it. This strategy is dangerous since the weight of the building may leave impressions on the concrete. Always follow the manufacturer’s directions. Please don’t use a concrete base until it’s ready.

Paving Slab Base

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Installing a paving slab base necessitates a different strategy. The first stage, like with concrete, is to gather your ingredients. You’ll need:

  • Paving slabs
  • Crushed rock.
  • Sharp sand
  • Spirit level.
  • Rubber mallet
  • A mortar-like compound.

Once you have the materials, the first step is to lay the sub-base. This phase is almost identical to concrete. You begin by excavating the ground to a depth of 100mm and filling it with hardcore appropriate for the weight and size of the garden workshop.

Next, add the sharp sand. It provides a soft and even bedding material for the pavings. (Concrete does not need this step because it can fill gaps surrounding the aggregate).

After that, lay the slabs. Professionals generally start at one corner and work their way around.

When laying every slab:

  • Make sure it is even with the spirit level.
  • Make sure it doesn’t wobble from side to side.
  • Make sure it reflects the general pattern or impact you wish to create.

If a slab isn’t level, use a rubber mallet to force it into the correct position. If desired, sprinkle more sharp sand underneath or around the slab to provide additional stability.

The third procedure is to “join the slabs,” which includes filling the gaps between them with a substance similar to mortar. Do not build the compound yourself; instead, use the one given by the vendor.

Sometimes, you must employ a slab breaker to cut slabs into the proper shape. These hew into the rock with diamond-edged cutters, breaking it into smaller shards.

If you need clarification on this phase, employ a professional to pre-cut slabs according to your foundation plan. This strategy reduces risk while improving the likelihood of a positive outcome.

Timber Sub-Frame Bases.

Timber sub-frame bases are the simplest to construct and require the least technical equipment. To construct a timber subframe foundation, you will need:

  • Use pressure-treated timber beams that are appropriate for the weight of your construction.
  • Concrete foundation blocks
  • Screws are provided.
  • Drill.
  • Spiritual level.
  • I saw
  • Sharp sand.

If you are still determining whether the timber is suitable for your garden workshop, speak with a timber merchant. Experts can offer the best outdoor wooden beams for use.

The concrete blocks or pads are placed first in the timber sub-frame base installation process. If you don’t already have any, you’ll need to put them in the ground and space them appropriately for the weight of the structure. Check that they are level with your spirit level; if not, add sharp sand.

Next, cut and install the timber beams (unless you bought pre-cut timber). Use a saw to cut the desired lengths of wood. Using the drill and screws, assemble the wood pieces according to your design.

Finally, place the completed foundation on the concrete pad. Use L-shaped metal brackets and secure them using concrete-specific screws.

Who will build the base?

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There are two options for constructing a foundation for your garden workshop:

  • Do it yourself with help from friends.
  • Professional “no-nonsense” professionals ensure peace of mind.

Building the foundation yourself is less expensive initially, but the risks are higher. While your friends may appear capable, the mistakes they make today could cost you later.

People with substantial building or construction experience should create bases for their vacation homes. If you’ve done work like this before, there’s no reason why you can’t apply the same principles to your property.

All three bases listed above require specialised construction knowledge. Concrete variations, on the other hand, are unquestionably the most complicated because they necessitate specialised equipment and expertise in levelling and curing.

If you already have concrete pillars or pads (or supporting masonry), installing a timber sub-base could be a DIY project. However, you must closely follow the layout designs and utilise the proper beams (heat and pressure-treated).

You might benefit from a professional “no-nonsense” approach if you’ve never built a foundation. This technique is more expensive at first, but it could save you money in the long term if you make mistakes.

Professionals, for example, bring their expertise to construction projects. Unlike do-it-yourselfers, they have years of experience doing similar work and understand all aspects of site preparation.

Better still, they can finish the job faster. Professionals spend less time on simple activities and work faster to complete projects.

Furthermore, hiring specialists rather than buddies will yield better results. Experts must stand behind their work and deliver high-quality results to be recognised. Someone you know in the community does not have to follow the same standards.

Finally, employing professionals is safer. Experts remove paving slabs and pour concrete daily, so they know the hazards. Amateurs may not. DIY work can result in splinters, stumbles, falls, and back, neck, hand, and toe injuries.

How Can First Choice Help You?

We at 1st Choice specialise in offering an extensive collection of quality timber, concrete and metal buildings, so you can be assured that you will find your ideal building with minimal fuss. There are occasions, however, when other specialists are required to complete your project, and our years of experience in this field mean that we have built up many valuable connections with reliable tradespeople whom we have put forward here for your consideration.

Whilst the individual tradespeople are independent of us (thus keeping the pricing as low as possible), we are happy to liaise with them to make arrangements on your behalf. We, therefore, take a deposit, which is passed along to them with your order. They will collect the balance outstanding upon completion of the works and leave you with an invoice for your records.

Prices quoted presume a suitable, accessible work site within 50 miles of our display area near Woking. If your site is further afield or access is poor, the standard quoted prices may be subject to an additional charge. You can find more details here.

Tips for Maintaining and Repairing Garden Building Bases

Garden-building bases are often relatively robust. However, they still require regular maintenance.

So, what should you do? Let’s find out.

Inspections occur regularly.

Regular inspections are required for optimum maintenance. Checking your base for damage keeps minor issues from worsening.

During an inspection, you should look for the following signs of deterioration or disrepair.

  • Damp areas remain even in warm weather or after storms pass. (Damp patches will seem darker on concrete and wood).
  • Concrete pads or beams that wobble or shift when contacted.
  • There are cracks in the base.
  • Rot can occur in wood-based items.
  • Position bases at a different angle than when they were placed. (Bases may occasionally shift due to ground movement or subsidence).
  • Soil is pushing on the foundation or bottom of the garden workshop.
  • Cracks or breaks in the jointing material of paving slab bases.
  • Uneven paving slabs.
  • Evidence of excessive aggregate or sand washing out from under the foundation (usually in the direction of draining water).

If your base is designed correctly, most examinations will reveal no issues. However, keeping an eye on it is critical because problems can be costly to fix if left unchecked.

Repairing cracks and damage.
Cracks in foundations can be cause for concern. However, your steps should be appropriate for the issue’s intensity.


Minor hairline cracks in concrete are probably not worth worrying about. Note them and take action if they worsen.

However, fissures in concrete larger than 6mm (about a quarter of an inch) must be filled. Leaving them can result in freeze-thaw weathering, in which ice freezes within and expands, pushing them apart. Over time, this process could cause structural damage.

To repair a concrete fracture, clear the area of any debris, such as leaves, soil, or twigs. Next, add concrete filler. Ensure that the filler is completely put into the crack. Filling it prevents dangerous water ingress (which causes the freeze-thaw damage mentioned previously).

Most professionals recommend applying flexible sealants to the repaired area after it has dried. These can expand and contract with the underlying crack and filler, sealing the patch.

Paving Slab

Paving slab bases can also crack. The severity of the damage determines the type of repair you adopt, just as it does with concrete bases.

To correct uneven slabs, add or remove sand beneath individual pavings. However, accessing them may entail removing your garden workshop from its pedestal.

Replace and rejoin any severely broken pavings. A single cracked paving can be divided into two slabs using appropriate jointing. Ensure that it is not load-bearing.

If you notice multiple cracks in your paving slab base, this may indicate earth movement or subsidence. Unfortunately, this situation may demand a complete reinstall on more stable terrain.

Timber Sub-Frame Bases.

Finally, timber sub-frame bases may crack in some cases. You will need to repair any non-superficial damage.

If you discover a minor crack in a beam, sand it to determine its depth. Superficial cracks sometimes appear to be more severe than they are.

If the crack widens, replace the beam. Unscrew it from the structure and replace it with a new piece of wood that fulfils your specifications.

Cracks may develop due to deterioration or insect attack. If this occurs, look for evidence of dampness and insect damage. Also, make sure you properly treat the beams before installing them. Most insects will avoid preservative-coated timber beams.

Water damage prevention

Reducing water damage entails stopping it from entering your base in the first place. Consider starting from the construction process.

The most straightforward technique to avoid water damage is to plan the base so that it slopes in one direction away from your buildings. A slight slope allows water to drain while providing a sturdy base. As previously stated, building a shallow angle while providing a stable foundation for your garden workshop is challenging, so many homeowners seek expert assistance.

You can also prevent water damage by ensuring enough drainage around your building. Using a suitable sub-base, drain lines, and gullies will allow your garden workshop to drain excess water during rainstorms. During your inspections, look for drainage that flows into the nearby land and waterways. Slowing the runoff can help to prevent flooding and restrict water from entering the excavated area.

Finally, consider the materials you use. Most professionals use waterproof concrete for their foundations. These compounds prevent porosity holes from emerging during the curing process. Waterproofing keeps moisture out of the substance, even with standing water.

Treating wood also helps to prevent water damage. Repeat this every couple of years or so.


Shows image of heavy duty base

After reading this guide, you should better grasp the significance of a sturdy foundation for your summer home. The structure above it must remain sturdy, level, and damp-free.

However, getting it right requires knowing what you’re doing. If you need more clarification, speak with an expert.

If you’re considering building a garden workshop in your yard, consider the ideal foundation. In some circumstances, concrete may be preferred over paving slabs. Consider the weight of your garden building and the type of soil.

What are you waiting for if you still need to start your garden workshop base project? Begin your project today and construct your own stunning getaway.

Frequently Asked Questions (FAQ) Garden Workshops

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  • Can you build a workshop on grass?

    Ensure your garden is adequately prepared prior to shed delivery. Avoid placing the workshop directly on a lawn, bare ground, or gravel. Doing so can cause subsidence, warping, and water damage. Choose a solid foundation for optimal stability and longevity.
  • Can you put a garden workshop on paving slabs?

    Yes, you can place a garden workshop on paving slabs. It is important to ensure that the paving slabs are level and stable to provide a sturdy foundation for the workshop. Using paving slabs can help reduce moisture and provide a clean and durable surface for your workshop. Make sure to properly secure the workshop to the slabs to prevent any movement or damage. Overall, placing a garden workshop on paving slabs is a practical and effective solution for creating a workspace in your outdoor area.
  • What is the best base for a garden workshop?

    The best base for a garden workshop is a solid concrete foundation. Concrete provides a stable and durable surface for your workshop, ensuring that it can withstand heavy equipment and frequent use. Additionally, a concrete base is resistant to moisture and will help prevent issues such as mold and rotting. It also provides a smooth and level surface for your workshop, making it easier to set up machinery and work on projects. Overall, a concrete base is a reliable choice for a garden workshop that will provide a sturdy and long-lasting foundation for your creative endeavors.

About Author:

Robin Antill is an established authority in the field of quality garden building manufacturing, boasting over four decades of experience. Having founded Titan Garden Buildings in 1979, he demonstrated a commitment to excellence from the outset by moving away from subpar materials and embarking on crafting buildings of superior quality.

His lineage of craftsmanship, traced back to his father and grandfather's business in Cleethorpes, underscores his dedication to quality and customer satisfaction. Robin's son, Craig, who joined the business in 1990, brings additional expertise, having honed his skills at Guildford College in joinery.

Together, they elevated Titan Garden Buildings, which eventually evolved into 1st Choice Leisure Buildings. Their enduring focus on premium materials, top-notch manufacturing, and unparalleled customer service, along with Craig's digital acumen in creating the company's online presence, showcase their expertise and reliability in the industry.

Robin’s expertise was featured in Realtor.com, Homes&Gardens, The London Economic, and dozens other publications.

Woking Show Site
1st Choice Leisure Buildings
Woking Garden Buildings Show Site
Sutton Green Garden Centre,
Whitmoor Ln, Sutton Green,
Phone 01483 237550