Suitable shed base on a slope

Question

Hi, I need some help with a shed build. My garden is sloped. The garden is approx 9/10m long and I would estimate the drop off at the rear of the garden to be about 2ft. I was thinking of putting the shed here at the bottom of the garden, would it be suitable, if yes , which type of base would be best suited?Thanks

William · Accepted Answer

Yes you can do this, dig of the area then install timber sleepers to act as retaining walls infill with mot type 1 then lay slabs on a bed of concrete

Roger · Answer

does your garden allow for a mini digger to enter it a small machine 1/2 to or1 ton  would do your job for you if not thers a few hours hard manual involved to dig your base . once dug your base till you reach solid ground you need 50 m  of sub hase put down and then tampacted in . once tis done your ready to put in wood shutttering around the base of your concrete pad  saw timber to size and place around your 6/4 bsae support timger with pins so when you lay concrete the timber doesnt give way. your know ready to mix concrete  a 3 to 1 general mix would suite . once you start mixing and laying concrete you need a piece of ti mber a foot or so longer than your base width to screen concret e  once you start laying concrete allow for a day before you walk or put preasure onpad JOB DONE

Sam · Answer

Morning Darren, there are a few types of sub bases which can be used most commonly is slabs however the most robust option would be to have a concrete base especially near a drop off area

Connor · Answer

Timber sleeper base with compacted hardcore and slabs or concrete inside

Ryan · Answer

Yes, provided:
	•	The ground is stable (not soft or boggy)
	•	You can create a perfectly level base
	•	Water can drain away from the shed (very important at the lowest point)

A 2 ft drop over 9–10 m is a gentle slope, but at the bottom the base still needs proper support.

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2️⃣ Best base options for a sloped garden

✅ BEST OPTION: Timber frame base on concrete pads / piers

Most common and practical solution

How it works:
	•	Dig holes for concrete pads or postcrete footings
	•	Pads are set level, stepping down the slope
	•	A pressure-treated timber frame is fixed on top
	•	Shed sits on the timber frame

Why it’s good:
✔ Handles slopes very well
✔ Keeps shed off damp ground
✔ Good airflow under shed
✔ Less digging than a full slab
✔ Easier and cheaper than retaining walls

Typical setup:
	•	Pads every 1.2–1.5 m
	•	Deeper pads at the downhill end
	•	Treated timber (UC4) for ground contact

💡 This is the method most professional shed installers use on slopes.

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⚠️ Option 2: Concrete slab with retaining edge

Only recommended if you want something very permanent

What’s needed:
	•	Dig into slope
	•	Build a small retaining wall (block or concrete)
	•	Hardcore + DPM + concrete slab

Pros:
✔ Extremely solid
✔ Ideal for large/heavy sheds or workshops

Cons:
❌ Most expensive
❌ Most labour
❌ Drainage must be done properly
❌ Overkill for standard sheds

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❌ NOT recommended on slopes
	•	Plastic grid bases without excavation
	•	Gravel bases without retaining edges
	•	Paving slabs laid directly on a slope

These will move over time at the bottom of the garden.

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3️⃣ Drainage (very important)

Because it’s at the lowest point:
	•	Slope ground away from the shed
	•	Leave 50–75 mm airflow under floor
	•	Consider a shallow French drain behind the shed if ground stays wet

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4️⃣ Shed size & weight considerations

Tell me if:
	•	Shed is under or over 8×6 ft
	•	Timber, metal, or composite
	•	Will it store heavy items or be a workshop

Heavier sheds = stronger base recommended.

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5️⃣ My recommendation for your garden

Given:
	•	~2 ft drop
	•	Bottom of garden
	•	Typical domestic shed

👉 Timber base on concrete pads / postcrete footings
This gives the best balance of cost, durability, drainage, and ease.

Kevin · Answer

Hi I would do a small footing and a brick retaining wall with weep holes , and then fill with concrete , unless your on a budget then think about using sleepers

Darrell · Answer

Depending on size of base I always recommend a reinforced concrete base minimum 130mm thick. 
The slope isnt a major issue, just obviously need your base frame level. If its deeper at one end you can back fill with hardcore.

Mark · Answer

Dig out level area and create a concrete base with dwarf wall to protect from weather

Lisa · Answer

I would advise a timer frame with compact concrete to enforce.

Michaela · Answer

I would advise to use timber sleepers to retain all the away around. Fill in woth type 1 mot stone and whacker in. Finish of with membrane, I stall gravel grids for stability and drainage. Fill the gravel grids with 20mm gravel. Shed can be laid on this and would never get damp or rotten due to the gravel grid system

Suitable shed base on a slope

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