Shed bases

[daiking]

I now have somewhere permanent to site a shed so I better do it properly. It has just spent 2 years sat on a tarp on the ground - although it is heavily shaded by mature trees that also suck the water out of the ground so the base was reasonably dry.

 

I have obviously googled shed bases and I can do anything from lay concrete footings and a concrete slab, to paving flags base and even a timber frame base. Assuming the cement mixer I acquired still works its probably worth me having a practice with that. The flaw in my plan is that even if the mixer works, I'll still need to hire a compactor for the hardcore.

 

I don't need something that you could build a house on but which way would you do it?

[ProDave]

Is it going on a bit of your newly infilled and leveled garden? If so you might have a problem with the ground settling.

 

In that situation I have put a shed base on wooden stakes (think short fence posts) driven into the ground and hammered in until they will go no more (into the underlying firm ground) Then support a timber base frame from that. then if the infilled ground settles, the shed won't move.

[Onoff]

I need to get rid of some hard-core so reckon I should get on with the shed (base) under the tree house. It's only about 10'x5'.

 

You honestly don't need to hire a compacter. I did my last base with a hand tamper. Just a weight on pole you lift and drop.

 

 

Edited July 17, 2017 by Onoff

[ProDave]

A wacker plate is a bit of equipment that one should buy, use, and then possibly sell on.

 

I have already hired mine out twice and that has covered about 1/3 what it cost me.

[Onoff]

Tbh I'll probably use my Evolution electric wacker plate seeing as I haven't made the other one yet! 

[daiking]

1 hour ago, ProDave said:

Is it going on a bit of your newly infilled and leveled garden? If so you might have a problem with the ground settling.

 

In that situation I have put a shed base on wooden stakes (think short fence posts) driven into the ground and hammered in until they will go no more (into the underlying firm ground) Then support a timber base frame from that. then if the infilled ground settles, the shed won't move.

It's down the bottom of the garden that hasn't been properly sorted. Just scraped off a little so the ground is fairly sound. The plan is to put membrane and mulch bark in that area anyway.

 

A bit of joinery wouldn't be bad experience either. And I have 3 pieces of 11mm OSB2 that I could layer to make a 6x8 shed floor. Posts could be concreted in as well, not just into the ground.

 

The playhouse sits on 4 posts bit that is going on the grass so that will have to wait a while. I'm just going to make 4 concretr pads for those legs. It was on paving stones before but I don't want to take up that much space this time.

[daiking]

37 minutes ago, Onoff said:

Tbh I'll probably use my Evolution electric wacker plate seeing as I haven't made the other one yet! 

 

The internetz sayz the 2.4hp petrol Evo is rubbish, let alone an electric one...

 

Not going on eBay or gumtree for one, I'd have no idea what I was looking for.

[Ferdinand]

Can you concrete galvanised scaffold poles into the ground and go off those?

 

If concerned about the thing moving I might incorporate something adjustable that can be relevelled without major trouble. Can I put another word in for Wallbarn Adjustable Support Pads even on one slab each... which can be obtained in varieties up to 400mm tall, or as heavy duty. 

http://www.wallbarn.com/products/roof-and-terrace-finishes/asp-adjustable-support-pads/

 

The normal ones ones cost a fiver and support just under half a tonne each. Wish I had them as I am going to have to jack my shed up this year because my fence post base has moved.

 

 

Edited July 17, 2017 by Ferdinand

[Barney12]

4 hours ago, daiking said:

 

The internetz sayz the 2.4hp petrol Evo is rubbish, let alone an electric one...

 

Not going on eBay or gumtree for one, I'd have no idea what I was looking for.

 

I have a petrol Evo. Is it rubbish? Well it depends on what you are comparing it against:

 

Is it as good as a hired heavy duty plate vibrator? No. Not even close. 

Is it capable of being lifted by one man? Yes.

Is it much, much more efficient than hand wacking? Yes and more yes. 

Would I use it to prep a very large area? No.

Is it good enough for shed bases, paths etc? Yes. 

 

Mine lives in the shed shed with a variety of other "stuff" and I find it useful. 

 

If buying again gain I think I'd look out for a second hand Belle unit. As @ProDave said it will likely get its money back again when you come to sell it. 

[daiking]

42 minutes ago, Barney12 said:

 

I have a petrol Evo. Is it rubbish? Well it depends on what you are comparing it against:

 

Is it as good as a hired heavy duty plate vibrator? No. Not even close. 

Is it capable of being lifted by one man? Yes.

Is it much, much more efficient than hand wacking? Yes and more yes. 

Would I use it to prep a very large area? No.

Is it good enough for shed bases, paths etc? Yes. 

 

Mine lives in the shed shed with a variety of other "stuff" and I find it useful. 

 

If buying again gain I think I'd look out for a second hand Belle unit. As @ProDave said it will likely get its money back again when you come to sell it. 

 

That's why it was internet with a z. I'm in no position to offer an opinion about the relative merits of any tools 

[Onoff]

No issues with my Evolution leccy wacker. 5kN is better than me doing it. Did the bathroom fine, 

[Onoff]

It's a shed base, not over critical. Plenty out there barely have the rubble compacted I bet. I would though add this to your concrete mix along with a sheet of mesh. Much less tamping as it is a deaerator too.

 

https://www.toolstation.com/shop/p80460?table=no

 

 

[Temp]

If the concrete is slightly bigger than the shed then rain can land on the surrounding concrete and run or be blown under the walls. To prevent this you can either:

 

a)  Make the slab the exact size of the shed with the top above ground level or

b) After laying the slab put the shed on a course of engineering bricks and a DPC (but there is a problem at the door).

 

Any other good ways to solve this issue? 

[daiking]

If I was looking and I'm not, but this isn't that far away and I've a mate near there who would help me to load it in the car.

 

This seems on the cheap for a £800 when new compactor.

[daiking]

6 hours ago, Temp said:

If the concrete is slightly bigger than the shed then rain can land on the surrounding concrete and run or be blown under the walls. To prevent this you can either:

 

a)  Make the slab the exact size of the shed with the top above ground level or

b) After laying the slab put the shed on a course of engineering bricks and a DPC (but there is a problem at the door).

 

Any other good ways to solve this issue? 

 

I hadn't got that far but the thought had crossed my mind.

 

I'm boxed into a corner at the moment, with my shed, in pieces, stacked at the bottom of the garden, a freshly laid lawn between me and it and little room to work in to pull everything out. To get the shed and measure up properly for the base.

[Ferdinand]

6 hours ago, Temp said:

If the concrete is slightly bigger than the shed then rain can land on the surrounding concrete and run or be blown under the walls. To prevent this you can either:

 

a)  Make the slab the exact size of the shed with the top above ground level or

b) After laying the slab put the shed on a course of engineering bricks and a DPC (but there is a problem at the door).

 

Any other good ways to solve this issue? 

 

You could put a layer of pavers on top the exact size of the shed, or a post base, then attach boxing in boards round the bottom.

[Siochair]

I once had a neighbour who used a plastic grid filled with stones/gravel as a shed base. No idea how long lasting it was as we both moved not long after. I do remember that it was pretty idiot proof to do. He managed both base and shed in just over a morning. I have no idea where he got it from but I am sure there are probably kits available.

[Onoff]

I wanted vermin proof so did a hard-core base with loads of broken sheet glass, sand blind, DPM then 4" concrete. I didn't bother with a DPM under the walls just tanked the inside floor and up the walls.

 

Tbh this was only to sit a crap freebie shed on and I had to make a new full size stable door. Also got rid of some 1863 stocks from the chimney on the first house.

 

 

Damp problems with the actual wooden shed but I could always ditch it and build up off the dwarf walls.

 

See how the old shed sits exactly atop the dwarf walls:

 

 

And tanked, wax paper then a floor:

 

 

But ffs don't listen to me, what I can't plagiarise I make up as I go along!

 

[daiking]

2 hours ago, Ferdinand said:

 

You could put a layer of pavers on top the exact size of the shed, or a post base, then attach boxing in boards round the bottom.

Isn't paving slabs a legitimate base anyway? Not sure why you'd do it 2 ways rather than just slabs only on a proper sub base.

[daiking]

1 hour ago, Siochair said:

I once had a neighbour who used a plastic grid filled with stones/gravel as a shed base. No idea how long lasting it was as we both moved not long after. I do remember that it was pretty idiot proof to do. He managed both base and shed in just over a morning. I have no idea where he got it from but I am sure there are probably kits available.

I've seen these by should really do something a bit more involved. If nothing else it's good practice.

[daiking]

1 hour ago, Onoff said:

I wanted vermin proof so did a hard-core base with loads of broken sheet glass, sand blind, DPM then 4" concrete. I didn't bother with a DPM under the walls just tanked the inside floor and up the walls.

 

Tbh this was only to sit a crap freebie shed on and I had to make a new full size stable door. Also got rid of some 1863 stocks from the chimney on the first house.

 

 

Damp problems with the actual wooden shed but I could always ditch it and build up off the dwarf walls.

 

See how the old shed sits exactly atop the dwarf walls:

 

 

And tanked, wax paper then a floor:

 

 

But ffs don't listen to me, what I can't plagiarise I make up as I go along!

 

I won't be going this far. It's just a shed. At most I might think about using foam tape as a gasket between mating surfaces. Something has to help stop the bugs, surely? 

[Onoff]

28 minutes ago, daiking said:

I won't be going this far. It's just a shed. At most I might think about using foam tape as a gasket between mating surfaces. Something has to help stop the bugs, surely? 

 

It's not that I go too far it's that I stray from the norm!  I had the blocks, bricks wax paper and liquid DPM etc and before I knew where I was..... 

[Ferdinand]

1 hour ago, daiking said:

Isn't paving slabs a legitimate base anyway? Not sure why you'd do it 2 ways rather than just slabs only on a proper sub base.

 

I was addressing the point about protecting the shed floor from blown rain and water running in etc. Via the top surface of the concrete slab. Raising it 2 inches with slabs or 4 inches with fence posts and adding a 'skirt' would achieve that simply.

 

F

 

Edited July 18, 2017 by Ferdinand

[Onoff]

21 hours ago, daiking said:

Isn't paving slabs a legitimate base anyway? Not sure why you'd do it 2 ways rather than just slabs only on a proper sub base.

 

It is my understanding that if you just lay paving slabs then there's no DPM and damp will eventually creep through. (I did once half consider laying a sheet DPM atop a damp, single garage floor then laying paving slabs.....it never happened).

 

I can't see why you couldn't lay a compacted base then blind with a strong, levelled sand/cement mix to keep it together. Then lay a DPM and slabs above this. A lot less work than mass concrete. Tbh, concreting isn't hard. This base took me about 4 hours to mix on my own. Included barrowing extra ballast from down the front of the plot. 10' x 8" I think and about 4" deep.

 

 

In your design you want to apply the old 6" rule to anything that can get wet i.e. wood. The old adage is that a rain drop hits the "deck" and bounces up 6". This is why traditionally the DPC is always a minimum 6" above the "ground". At least that's my understanding as to the "why".

 

 

[daiking]

23 minutes ago, Onoff said:

 

It is my understanding that if you just lay paving slabs then there's no DPM and damp will eventually creep through. (I did once half consider laying a sheet DPM atop a damp, single garage floor then laying paving slabs.....it never happened).

 

I can't see why you couldn't lay a compacted base then blind with a strong, levelled sand/cement mix to keep it together. Then lay a DPM and slabs above this. A lot less work than mass concrete. Tbh, concreting isn't hard. This base took me about 4 hours to mix on my own. Included barrowing extra ballast from down the front of the plot. 10' x 8" I think and about 4" deep.

 

 

In your design you want to apply the old 6" rule to anything that can get wet i.e. wood. The old adage is that a rain drop hits the "deck" and bounces up 6". This is why traditionally the DPC is always a minimum 6" above the "ground". At least that's my understanding as to the "why".

 

 

The paving slab bases I've researched are laid on a sand/cement (8:1) bed. Im not that bothered by the whole damp thing. Shed was free and is probably 60+ years old. 

 

Don't expect 6" of rain bounce when it's sheltered by trees and surrounded by bark mulch.