Lifting and leveling slabs for shed base

[StevenF]

Hello,

I'm looking to build a 14x10' shed in my garden and plan on using a slab base. All of my garden is slabbed anyway but the section where the shed is going to go is not level. You can see the area marked out in the image below (I was going to build it myself that shape but have decided to go for a standard size at 14x10).

Shed Sizing

• StevenF
• 26 Jan 2016

At the moment the slabs are just layed on top of some sort of fine black substance (I know nothing about garden DIY!) And they aren't cemented down.

I was wondering what the best way to tackle it would be. You can see the patio has a 2" or so drop and at very end of the shed which I would like to remove, otherwise the shed will be quite high up (by the time it is built on a wooden frame ) and I would struggle to get my motorbike in it.

I hope this make sense and appreciate any help given!

Thank you

 

[r896neo]

Unless this is a super light trials bike or similar then you will definately need to do some decent work.

I would recommend that the shed area had at least a 75mm sub base and the flags must be laid on a sand and cement bedding and ideally pointed with mortar to create a fully rigid pavement.

The weight of a motorbike rolling over flags will cause a rotation effect as the leading edge of the flag is weighted it will want to flip the other side up so the flags must be stuck down and pointed to avoid this.

Are you planning to put a timber floor in the shed or use the flags as a floor?

 

[StevenF]

Thanks for your reply.

The shed I'm buying comes with a 22mm floor and I was going to pay extra for more extra floor beams. I had thought about using the slabs as the flooring but the shed I'm looking at comes with one.

What would you recommend I do with the edging that is in place with the 2-3 inch drop? I'm hoping to keep the cost down as much as possible because the shed alone is just short of £1300.

 

[OuterSpaceHopper]

Hi Steven, if the shed includes a 22mm floor panel, and that is on top of floor beams, how much over your current patio slab height is the floor of your shed going to be?
The shed base might might double the height of the obstacle you have with your existing edging?

Can you ramp the pavers in front of the shed up to the door, over that distance you might not noticed the angle, even with a big bike?

My garden sloped and I needed a flat(well, slightly sloped for drainage) area for a 10x8 foot shed.
The shed had a base made from 70mm decking timbers like these
http://www.wickes.co.uk/Wickes-Easy-Deck-Bearer-3m/p/540523

I created a flat area recessed into the slope of the garden at just the right depth for the slabs, timber so that the shed floor was just above the grade of the garden.
Around the recess I buried a shingle and land drain pipe around the edge of it. This ran into a soakaway on the other side of the garden.

I compacted the soil with a hand held rammer. Then I put a barrier sheet down, the paving slabs on top of that, with another barrier sheet on top of that. I bolted the decking timbers to the paving slabs with masonry anchor bolts.
Around the edge of the decking timbers and pavers I staked in some decking boards side on, then graded the garden soil up to the edge of the boards. The decking boards just kept the soil off the base timbers, kind of sacrificial!

This took me a whole weekend to sort out.

When I dismantled the whole thing 7 years later, the pavers were still exactly flat and there was not a single weed growing through the base.
The whole thing was also dry, which is probably why the shed did not suffer condensation like most metal sheds do.

I've only done a small amount of paving, but I reckon it would be easier and cheaper(couple of bulk bags of sand, plus some cement?) to incline the pavers in front of your shed, rather than go to the trouble of recessing the shed into the ground, with all the ground water trouble that might bring.

Will a 22mm shed floor support the weight of your bike? I reckon you would need quite a few bearers under the floor to support the floor panel?

 

[StevenF]

Hi Steven, if the shed includes a 22mm floor panel, and that is on top of floor beams, how much over your current patio slab height is the floor of your shed going to be?
The shed base might might double the height of the obstacle you have with your existing edging?

Can you ramp the pavers in front of the shed up to the door, over that distance you might not noticed the angle, even with a big bike?

My garden sloped and I needed a flat(well, slightly sloped for drainage) area for a 10x8 foot shed.
The shed had a base made from 70mm decking timbers like these
http://www.wickes.co.uk/Wickes-Easy-Deck-Bearer-3m/p/540523

I created a flat area recessed into the slope of the garden at just the right depth for the slabs, timber so that the shed floor was just above the grade of the garden.
Around the recess I buried a shingle and land drain pipe around the edge of it. This ran into a soakaway on the other side of the garden.

I compacted the soil with a hand held rammer. Then I put a barrier sheet down, the paving slabs on top of that, with another barrier sheet on top of that. I bolted the decking timbers to the paving slabs with masonry anchor bolts.
Around the edge of the decking timbers and pavers I staked in some decking boards side on, then graded the garden soil up to the edge of the boards. The decking boards just kept the soil off the base timbers, kind of sacrificial!

This took me a whole weekend to sort out.

When I dismantled the whole thing 7 years later, the pavers were still exactly flat and there was not a single weed growing through the base.
The whole thing was also dry, which is probably why the shed did not suffer condensation like most metal sheds do.

I've only done a small amount of paving, but I reckon it would be easier and cheaper(couple of bulk bags of sand, plus some cement?) to incline the pavers in front of your shed, rather than go to the trouble of recessing the shed into the ground, with all the ground water trouble that might bring.

Will a 22mm shed floor support the weight of your bike? I reckon you would need quite a few bearers under the floor to support the floor panel?

Hi ,

The shed floor will be made with 3x2's and 22mm tongue and grove cladding floor. I was hoping that would be enough to support a motorbike, tools and gardening equipment etc? I did think about making the slabs as the shed flooring, do you think that would he a better idea?

I like the idea you've done. I could dig down a few inches to make he slabs slightly bellow the rest of the patio, allowing the shed to sit level.

I got some work done today and lifted all the slabs for the area the shed will be going in. They were just sitting on top of a sand like material.

Being a completely gardening beginner, would someone be able to give me some advice about what I should be doing next? How much should I did and what materials should I be using to lay the slabs?

Sorry for all the questions!

 

[OuterSpaceHopper]

Hi Steve, 22mm tongue and grove is pretty strong I would have thought. What are the centers of the 3x2s? I only had 18mm ply, on 70mm timbers at 60cm centers. I think this would have held a motorbike without a problem.

I notice you have some standing water next to the bush, I guess you are relocating the bush, so the water might get worse? Perhaps it is due to the garden fabric, but if there is already pooling, I might be reluctant to recess anything but the pavers, or you might end up with your timbers sat in water. Even if you do recess the pavers it is worth having somewhere for any water to drain away round the edge of them. It was surprising how much rain water the shed used to spill! I used a flexible perforated land drain pipe that I bought on ebay for a couple of quid. This was surrounded by pea shingle and drained into the deepest hole that I could dig on the other side of the garden. I filled this with bricks, builders rubble and pea shingle. I capped it with a couple of pavers to stop soil subsideing into the void from above and blocking it up.

My garden was extremely wet, water used to pool against a retaining wall at the end of the garden with nowhere to go. The soak away fixed this, as it seemed that a layer of capping clay beneath the soil was preventing the garden draining. It worked but it could have gone the other way and the soakaway might have allowed ground water to come up and drown my shed base!

I made sure the pavers had a slight slope(I think 2 cm over 3 meters) to allow any water that ended up there to drain out, but I don't think it ever got wet under there.

I painted the timber barers with bitumen type paint(like the stuff for shed roofs).

I only rented the house, so I could not lay the pavers on sand and cement, only soil, so I had to make sure I could put the ground back when I left if the landlord didn't want the shed(in the end he didn't!)
Just compacting the soil and using a membrane(just cheap, not the building regs expensive type) worked though and there was not a single weed or worm when I took it up!

If I did it again at my own house, I would get a couple of bags of bulk sand and dry mix with cement, as this would be easier to compact and level than soil. Also less likely to be undermined in the future by roots, worms and ants!

I in no way an expert, I've only installed one shed and one short path, but if I was you I think I would be looking to put in a pea shingle drain round the edge of the shed, making sure that the ground cannot subside into the drain and destabilize your shed base. Recess slightly at the shed location and gently grade a slope the approach to the shed

This website is the definitive word in paving. it is brilliant!

http://www.pavingexpert.com/

Leave a gap round the edge for fence maintenance and to allow you to build the shed!

 

[theprinceofdarkness]

You can see the slab underlay(?) sloping towards the fence. It looks as though your ground is higher then your neighbours. This is a severe problem.
I have a one ton milling machine in my shed and a lathe. The secret is to transfer the weight straight through the flooring boards through a joist into the ground. If the weight of your motor bike exceeds , say 400 lbs, then I would put a wide thick board (like a scaffold board) down the centre and use that to wheel your bike on and an extra bit for your centre stand. A side stand does not take much weight. You could make a bumpy slope just with paving stones.
Frank

 

[snappyfish]

Did you finish this?