Shed under a large tree

[NickXX]

Hi all,

I want to build a shed under a large (Yew) tree as it's probably the best spot in the garden for a 10x8ft shed, and isn't visible from the house. Are there shed bases which are designed for going over roots? I'm not worried about movement as it's a mature tree, but more about getting water to the tree roots.

Positives:
- The area is dry/shaded, so not much actually grows in the space.
- Out of sight of the house.

Negatives:
- I'm worried that building a shed over the root area might harm the tree.
- Mossy/dirty looking roof? I'd keep on top of keeping the roof clear, but maybe tree sap would be a never ending battle.


It will mostly be for storing garden tools and bits, but it would be nice if it looked decorative, so I'm tempted by either a summer shed/potting shed from Tiger.

https://www.tigersheds.com/product/tiger-summer-sh...
https://www.tigersheds.com/product/tiger-potting-s...

Does this look like a reasonable location, or will I end up with a filthy shed and a dead tree?

Thanks,
Nick

[Snow and Rocks]

I had a largish shed (10m x 5m) in a similar location that was there for at least 30 years with no issues apart from the shed eventually rotting around the base - the lack of gutters causing rain to run down the walls.

I've recently replaced it and included large overhangs which means the water dripping from the gutterless roof doesn't soak the shed walls and is still able to get to the ground to water the tree.

[hidetheelephants]

Yew is likely to cover the roof in green stuff. Screw piles/ground screws might be the best way to avoid root damage.

[Panamax]

Get a shed with a proper wooden floor and support it on some concrete blocks. Make sure the roof of the shed drains in such a way that the rain water still gets to the tree. No problem at all.

[Roboticarm]

I had a shed with basically sat on metal posts I to the ground attached to a frame upon which the shed base sat, about half a foot off the ground. Was sturdy enough to hold a motorbike too.

Something like this https://www.diy.com/departments/quickjack-6ft-x-4f...

Helps on uneven ground so should help you avoid the roots

Edited by Roboticarm on Sunday 21st April 21:20

[Simpo Two]

hidetheelephants said:

Screw piles/ground screws might be the best way to avoid root damage.

Makes sense to me. Metposts are another option.

Also note that the area of tree roots that absorb water are around the periphery so they get the water that drains off the canopy. The closer to the trunk, the less important it is.

[NickXX]

Thanks all. I’ve seen wooden frames with 4 spikes at each corner which look like a very simple solution to get the base raised off the ground and level. Are there any problems with these? They seem too good to be true compared to a gravel/concrete base.

I’m guessing that the big negative is that the shed is about 1 foot off the ground, so might be difficult getting heavy stuff in/out (not that I’ll be storing anything heavy in it).

[NickXX]

Roboticarm said:

I had a shed with basically sat on metal posts I to the ground attached to a frame upon which the shed base sat, about half a foot off the ground. Was sturdy enough to hold a motorbike too.

Something like this https://www.diy.com/departments/quickjack-6ft-x-4f...

Helps on uneven ground so should help you avoid the roots

Edited by Roboticarm on Sunday 21st April 21:20

Thanks - this looks perfect.

[Andeh1]

Dig out any loose soil, stamp it down well, builders sand and paving slabs?

It's a full body work out, but would do the job fine.

Ignore the temp roof, need to get proper shed felt.

[OutInTheShed]

NickXX said:

Thanks all. I’ve seen wooden frames with 4 spikes at each corner which look like a very simple solution to get the base raised off the ground and level. Are there any problems with these? They seem too good to be true compared to a gravel/concrete base.

I’m guessing that the big negative is that the shed is about 1 foot off the ground, so might be difficult getting heavy stuff in/out (not that I’ll be storing anything heavy in it).

A lot of sheds sit on a few timber 'bearers', so you maybe only need 6 or 8 'pads' for it to sit on. Those pads can be small areas of concrete in the ground, or just small slabs on some gravel. Just shove some wedges in when it inevitably subsides a bit in due course.
You either want a wood floor off the ground to keep it dry, or a serious slab with DPC.
You need a realistic idea of what load you're going to put in there! And how much you can cope with the floor deflecting.

[biggiles]

NickXX said:

but more about getting water to the tree roots.

The rain will run off the shed into the ground anyway, so it's probably not worth worrying about. If you are concerned, perhaps route a gutter into a soakaway in the ground so you know where the water is. The roots will find it.

[Aluminati]

You can just see our shed totally under trees. ( The old looking cladding covers a ply box)

Sits on screw anchors 6” off the ground and has done for 6-7 years without issue.

[NickXX]

Aluminati said:

You can just see our shed totally under trees. ( The old looking cladding covers a ply box)

Sits on screw anchors 6” off the ground and has done for 6-7 years without issue.

Thank you - is it a wooden framed base that you have sitting on the anchors (which the shed then sits on)?

[Aluminati]

NickXX said:

Thank you - is it a wooden framed base that you have sitting on the anchors (which the shed then sits on)?

It is. Base frame is 6x2 with an 18mm ply floor. Walls/roof 4x2 with 18mm ply.

[defblade]

A quick google on yew roots:

"It should be noted that, while structural roots will generally be confined to beneath the crown spread,
smaller-diameter roots extend much further: at least as far as tree height measured radially
and often to 2.5 times the crown spread, depending on rooting conditions/subterranean
barriers to rooting etc."

I don't think your shed will affect the tree much

[ATG]

Andeh1 said:

Dig out any loose soil, stamp it down well, builders sand and paving slabs?

It's a full body work out, but would do the job fine.

Ignore the temp roof, need to get proper shed felt.

He's trying to avoid damaging the tree, so that wouldn't be a good solution.

Typically a tree's roots spread out as much as its canopy does. You should try to avoid contacting the soil in that area. The screw supports sound ideal. You could even loosen up the soil between the four screws before you assemble the shed. Might as well take an opportunity to improve the soil as no one is going to compact it once the shed is above it. You could direct the water from the shed's roof back under the shed too. If it is elevated a few inches so that air moves freely under it, that water won't do the shed any harm.

[Pheo]

Loads of options.

Ground screws - although if you hit a root that is not great

Loads of ground bearing options eg swift foundations. Or even arguably a levelled set of concrete blocks, or two timber bearers.

Just google shed based and loads of options are possible which don’t involve disturbing the ground much.

[RC1807]

Even hitting a few roots with ground screws won't kill the tree.

I had a shed base and a deck base built last year. Both required some ground to be cleared and some border beech hedge roots were cut through in the process. The hedge has come back to full leaf again, so the damaged roots weren't the majority.
It'll be the same for this tree.