Piers for shed on sloping ground

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Hi All,

I would like to install a shed in my garden. I have quite a few bikes plus tools plus garden equipment so I'm considering a reasonably large shed of 12ft x 6ft (3.7M x 1.8M).

The issue I have is that the location where I would like to place the shed is sloping away from the house towards a mini-retaining wall which is 30cm tall.

View media item 106872
Constructing a level concrete base in such circumstances would require a lot of concrete for a DIYer with no mixer and no access to the garden from the front to allow a concrete truck to supply the mix.

This is when I noticed the brick piers left behind by the previous owner. There are 4 in the picture which are 192cm apart parallel to the fence and 136cm apart coming towards you. They're level enough except for the one in the front left of the picture which is 20mm lower.

So I thought I could construct 5 more piers, 2 to extend the length to the side where I've removed the paving slabs on the right of the picture and 3 in the front. I could then install some timbers on top of these piers and screw some sheet material (OSB? Ply?) to the timbers and stick the shed on top.

Does this sound like a viable solution? What dimension of timbers should I use? Can the timbers be laid directly on the piers and be held in place by gravity once the shed is installed?

For the construction of the piers I was proposing to dig a hole 2ft deep, pour in some hand-mixed concrete, level it off and then build off it using bricks and mortar. Does the concrete need to be special for this purpose or can I use a standard 6 parts ballast + 1 part cement?

Do the bricks need to be engineering bricks? For the mortar I've seen a standard mix is 4 parts sharp sand + 1 part cement, is that okay?

Anything else that I've forgotten that is pertinent?

Many thanks for your help
 
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Couldn't you either build timber frame at the correct height to surround the dug hole, or dig in some paving slabs on edge to frame the hole, dug in to maintain a level?
Then fill with concrete.

My shed is 30 years old and simply sits on 4/5 4" fence posts as sleepers.
The bearers/sleepers were given a bloody good dose of creosote when laid and the shed relies on gravity to stay put
 
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Hi @Tigercubrider

Thanks for the reply. The reason I've suggested what I have is due to the presence of the 4 brick piers shown in the picture.

Additionally, I'd have to mix any concrete by hand so I'm trying minimise that as I imagine that pouring in batches would just lead to lots of cracking.
 
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Hi @Tigercubrider

Thanks for the reply. The reason I've suggested what I have is due to the presence of the 4 brick piers shown in the picture.

Additionally, I'd have to mix any concrete by hand so I'm trying minimise that as I imagine that pouring in batches would just lead to lots of cracking.

put in some pads.

you can dig out some holes about the size you would do for a fence post, then put in a length of stud and cast in place.



Or dig out a slightly bigger hole and concrete, then build up with some concrete blocks to get to the height you need.
 
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Another option I'm considering is shuttering around the edge and laying a dry mix of sand and cement with paving slabs on top.

That way I don't have to rush to get it level before it goes off.

The sides could be supported with concrete edge stones to stop the edge spreading when weight is applied?

Thinking aloud now. Anyone done something similar?
 
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put in some pads.

you can dig out some holes about the size you would do for a fence post, then put in a length of stud and cast in place.



Or dig out a slightly bigger hole and concrete, then build up with some concrete blocks to get to the height you need.
Interesting video. Unfortunately I don't have access to the equipment required for cutting and drill the sections of steel that the timbers are supported by.
 
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Hi All,

I would like to install a shed in my garden. I have quite a few bikes plus tools plus garden equipment so I'm considering a reasonably large shed of 12ft x 6ft (3.7M x 1.8M).

The issue I have is that the location where I would like to place the shed is sloping away from the house towards a mini-retaining wall which is 30cm tall.

View media item 106872
Constructing a level concrete base in such circumstances would require a lot of concrete for a DIYer with no mixer and no access to the garden from the front to allow a concrete truck to supply the mix.

This is when I noticed the brick piers left behind by the previous owner. There are 4 in the picture which are 192cm apart parallel to the fence and 136cm apart coming towards you. They're level enough except for the one in the front left of the picture which is 20mm lower.

So I thought I could construct 5 more piers, 2 to extend the length to the side where I've removed the paving slabs on the right of the picture and 3 in the front. I could then install some timbers on top of these piers and screw some sheet material (OSB? Ply?) to the timbers and stick the shed on top.

Does this sound like a viable solution? What dimension of timbers should I use? Can the timbers be laid directly on the piers and be held in place by gravity once the shed is installed?

For the construction of the piers I was proposing to dig a hole 2ft deep, pour in some hand-mixed concrete, level it off and then build off it using bricks and mortar. Does the concrete need to be special for this purpose or can I use a standard 6 parts ballast + 1 part cement?

Do the bricks need to be engineering bricks? For the mortar I've seen a standard mix is 4 parts sharp sand + 1 part cement, is that okay?

Anything else that I've forgotten that is pertinent?

Many thanks for your help

Hi Curium,

For the floor I would use 18mm external grade ply. However your shed will need to totally cover this eventually otherwise it will swell and deform. Unless you put a serious waterproofing treatment on it.

For the floor timbers I would use 2 x 5's on 16 inch centres. Which you double at the edges to support the weight of the walls. Even though 2 x 4 would probably meet your requirements and would be adequate for your spans 2 x 5's seem much more solid to walk on.

I would use 7n dense blocks sat on a 10cm layer of MOT Type 1. If you have to stack them you want to get a good layer of mortar between them. I would use sharp sand for this with cement. 4 or 5:1 You will need stack or dig down until you find each one level starting from the highest point of the ground. You can use anything from 4:1 to 6:1. 4:1 is stronger though, but will dry faster. So take that into consideration depending on how familiar you are with concrete.

You can use 90 x 90 galvanised angle brackets from toolstation which can be secured to the 7n concrete blocks with concrete bolts which you have to pilot a 8 or 10mm whole for. You will need an sds drill for this though. You can use coach screws with a washer to secure the brackets to the timber. Since its not a massive building coach screws should be fine

It is normal to find yourself having many more questions, however there is a tonne of stuff on YouTube etc to help you these days.

Hope this helps
 

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