Base on Garden Decline

[Williams]

I have a back garden mostly of concrete slab and tarmac. It angles down and away from the house. Picture attached.

 

I'm planning on changing the shed to a plastic Kettar 3m x 2m.

Problem is I need a level base to construct it on. 

 

I have a few ideas on ways to level the surface. But is their any experienced views on efficient base construction over tarmac?

 

Thanks in advance.

[saveasteading]

A concrete slab raised above the existing is best.

You could potentially just lay slabs instead. 

Then bolt it down.

What is going in the shed?

[Williams]

Inside the shed - various household storage, tools.

 

My initial plan was to resurface with concrete.

 

I'll do some research on the slabs idea. It may be an easier option given the different types of surfaces I'm working with. 

[saveasteading]

4 hours ago, Williams said:

the slabs idea

My greenhouse is set on 6 slabs (4 corners and 2 mids) with gravel in a grid for the floor. the structure is bolted down with 6 chemical bolts and has withstood many gales.

However, draughts and dampness don't matter for a greenhouse but might for your shed, so consider how the rain is 'shed' away.

[bassanclan]

I think that if the whole garden is on a constant slope, you could just work with the slope and build it off the existing slabs, so long as they are flat, rather than level

[saveasteading]

6 hours ago, bassanclan said:

so long as they are flat, rather than level

I would always go for level as well as flat. Anything off level can cause twisting and stresses, especially at the door.

[Williams]

On 20/08/2022 at 12:03, bassanclan said:

I think that if the whole garden is on a constant slope, you could just work with the slope and build it off the existing slabs, so long as they are flat, rather than level

Thanks for the tip.

Unfortunately with the tarmac the slope can be quite random. 

With the size of the shed I will have to dig a new foundation.

[Williams]

Well I started today and dug up a foundation.

 

My house is an inner city semi-detached, hence the smaller gardens.

The tarmac had a compacted sub base - which I can use for the new foundation. 

 

But on lifting up the paving slabs it was full of tree roots which are literally touching the surface. See picture.

It would also explain why the paving has become uneven near my house now. When I step into my back garden the first paving slab sinks under my body weight.

 

2 years ago my neighbour planted a tree adjacent to the border fence. It has grown pretty quick - now the height of my bedroom window so I can touch the branches. It's about 2 meters from my house (the houses were built staggered) and about 4m from my neighbours house.

 

I'm not sure what to do moving forward.

 

1. I need a level foundation, so to get 10cm deep with sub base and mortar I will have to dig deeper than the tree roots. Can I cut them out? What if it damages the tree?

2. I'm now also worried of the long term damage that the tree could cause. In 2 years it's the height beyond my bedroom window with roots affecting the paving to my door. What's gonna happen in 4-5 years time. 

3. I was reading trees should be planted minimum of 4m from a house.

4. Additionally my neighbour has planted a row of Laurels inches from my external side of house (my semi-detached house faces their garden). I was reading bushes should be 4 feet from a house foundation.

 

If it's not going to cause any damage I'm not bothered. But if there is a risk then thousands of £££ is not worth a tree.

 

Does anyone have any experience / insight to tree root damage?