Concrete shed base

[v14]

I'm in the process of laying a concrete base for an 10x8 shed in the back garden.

Ground has been dug out 6in and formed with 7x1in ply boards.

I've been advised by someone who knows (allegedly) that due to the thickness of the pour it won't need a hardcore sub base.

before I go and waste 1.5m3 of concrete what da ya thinks?

 

[Dutcho]

No expert but for a shed I would of thought it would be fine, for a hard standing, drive or something, then yes I would put a hard core base in first.

 

[gegar]

wouldnt of thought but what s ground like if its badly drained or bogy might be worth doing it wright in first place

 

[mozr]

I did one similar a few years back.

As long as you dig down, and the surface is reasonably compact and sturdy you will be ok.

Have you built a retaining wall or put edging stones in?

Are you using any metal mesh to reinforce it?

It also wouldn't hurt to throw a few bags of hardcore down, and might save you cash on the concrete.

 

[v14]

I did one similar a few years back.

As long as you dig down, and the surface is reasonably compact and sturdy you will be ok.

Have you built a retaining wall or put edging stones in?

Are you using any metal mesh to reinforce it?

It also wouldn't hurt to throw a few bags of hardcore down, and might save you cash on the concrete.

No retaining wall, it's just dug down 6in and sides formed with 7in boards which protrude 1in over the top of the sides.

I've got some 5mm steel mesh to reinforce.

I think it should be ok, but every guide I can find on the internets say to lay down 3in of compacted hardcore.

Doesn't look like it'll be getting done this weekend so that gives me another week to convince myself I don't need the hardcore.

 

[mozr]

Are you getting the concrete mixed to order?

I used a great firm that mixed as they were barrowing (I have 6 steps to house), so paid for exactly how much I used.

Do you think you will need the additive in it to prevent cracking from frost whilst its curing?

It's cold at night.

 

[v14]

Yes mate, readymix pay for what you use type setup.

I've been quoted £90 per m3 which includes barrowing in, would that be about right?

Don't think frost will be a problem for a few weeks yet, low temp of 7 °C forecast for this weekend.



edit: Just phoned to confirm price for concrete, it's actually £135 per m3 +vat.

 

[mozr]

Good price actually.

Take it!

 

[benny59]

I'm in the process of laying a concrete base for an 10x8 shed in the back garden.

Ground has been dug out 6in and formed with 7x1in ply boards.

I've been advised by someone who knows (allegedly) that due to the thickness of the pour it won't need a hardcore sub base.

before I go and waste 1.5m3 of concrete what da ya thinks?

if the ground is free draining it shouldn't be a problem m8 {provided you compact the soil with a wacker plate or something similer} afterall you will have to hire a wacker to compact the hardcore

do a fair bit of concreteing in my backgarden and never used any hardcore

just finished a shed base earlier in the summer

 

[mozr]

edit: Just phoned to confirm price for concrete, it's actually £135 per m3 +vat.

I paid £140 for .98 cubic metre about two years ago, so that is about right mate.

 

[v14]

I paid £140 for .98 cubic metre about two years ago, so that is about right mate.

Bit dearer than the £90 they told me 2 weeks ago though.

When he said £135 +vat I told him I spoke to a woman 2 weeks ago and she quoted £90..

he said "nah m8... ignore that ..she talks a load of shit" lol.

But TBH I did think £90 was very cheap.. hey ho.


Anyhoo thanks for the help DW'ers :Cheers:

 

[PollyPhfiller]

No retaining wall, it's just dug down 6in and sides formed with 7in boards which protrude 1in over the top of the sides.

I've got some 5mm steel mesh to reinforce.

I think it should be ok, but every guide I can find on the internets say to lay down 3in of compacted hardcore.

Doesn't look like it'll be getting done this weekend so that gives me another week to convince myself I don't need the hardcore.

Hardcore minimum of 3inc is a must for large out-houses so to speak but for your piddly shed just 6inches of concrete within boards will total do the job

Just crack on with it

 

[baron]

Why not sit the shed on concrete blocks it shouldnt need a full base
use plenty of blocks,it will work out cheaper plus give you good ventilation

 

[chrispeters]

when we put our shed up ....
we just sand and cemented evenly placed flags nice and level ...
then just put the shed on them !! had no bother in 2 years.

 

[tlogic]

If I was you I would think about putting down some sort of reinfored mesh than pour concrete over it if you don't when the concrete starts to harden you might run the risk of the concrete cracking. concrete performs well in compression but not so good in tension hence the reason for reinforcement.

 

[Messa]

Its just a shed ffs, no need to pile-drive pal just chuck some old flags down on some dab and erect the bugger.

6" is more than enough pal, unless you are talking to my wife.

 

[stihl260]

For the Job you are planing, your method will be fine.
Some people on here seem be getting confused between the weight of the average shed and contents and a full blown construction project.
Trust me i have done hundreds of shed, summerhouse and workshop bases over the years and never had to go back because of cracking.
If the ground is firm and well drained then it will be ok.
I live in the Fens and round here the ground moves and cracks with shrinkage.
As long as you place the reinforcement in there, i can assure you it will be fine for years.
As for the of anti Frost additives (its already in there if its from one of the more well known firms), Gemix, Cemex, Lafarge.
Most small sheds are usually put on Slabs with a good 3" 20mm type 1 or Limestone which is whacked down, then a 6 to 1 mix of Sharp sand and OP cement, with some feb mix plastisising agent in the mix to increase pliability in the mix and increase adhesion to the slabs.
Haunch up mix at a 45 degree angel all round the edge of the slabs to stengthen and bond the slabs together.
In the relms of groundwork and contruction they use a Gen 0 semi dry Kerbing mix for setting and haunching Kerb stones.
By the time you have paid out for the Sub base, whacker plate hire, Sand, cement , Slabs and hired a cement mixer , the readymix is easier, faster and in the end cheaper!
Before anyone says, but your a Tree Surgeon ! I'm actually A Landscape Gardener, Groundsman and Hard Landscaper and a Blo*dy good Arb Man.
A man of many talents, mostly legal ,Lol

 

[v14]

Its just a shed ffs, no need to pile-drive pal just chuck some old flags down on some dab and erect the bugger.

6" is more than enough pal, unless you are talking to my wife.

flags on some dab indeed you feckin chancer

For the Job you are planing, your method will be fine.
Some people on here seem be getting confused between the weight of the average shed and contents and a full blown construction project.
Trust me i have done hundreds of shed, summerhouse and workshop bases over the years and never had to go back because of cracking.
If the ground is firm and well drained then it will be ok.
I live in the Fens and round here the ground moves and cracks with shrinkage.
As long as you place the reinforcement in there, i can assure you it will be fine for years.
As for the of anti Frost additives (its already in there if its from one of the more well known firms), Gemix, Cemex, Lafarge.
Most small sheds are usually put on Slabs with a good 3" 20mm type 1 or Limestone which is whacked down, then a 6 to 1 mix of Sharp sand and OP cement, with some feb mix plastisising agent in the mix to increase pliability in the mix and increase adhesion to the slabs.
Haunch up mix at a 45 degree angel all round the edge of the slabs to stengthen and bond the slabs together.
In the relms of groundwork and contruction they use a Gen 0 semi dry Kerbing mix for setting and haunching Kerb stones.
By the time you have paid out for the Sub base, whacker plate hire, Sand, cement , Slabs and hired a cement mixer , the readymix is easier, faster and in the end cheaper!
Before anyone says, but your a Tree Surgeon ! I'm actually A Landscape Gardener, Groundsman and Hard Landscaper and a Blo*dy good Arb Man.
A man of many talents, mostly legal ,Lol

M8 you should be the official DW Landscape Gardener..

Always an excellent reply to these sort of things. :Clap:

Not like that Messa caant lol

 

[Munkey]

Build your 6x2 frame. Make sure the levels are spot on
Get a brick and beat down the loose soil, flatten it out as much as you can
Lay down your DPM
Mix your own concrete with a 4-1 mix (beg or borrow a cement mixer)
Get a 4x2 that goes end to end on your frame and level the concrete out.

You'll have the job done for next to nothing as a ton of ballast costs £40 rather than the ready mix which costs a few times that. Personally I wouldn't add anything to the mix unless it is very cold. You don't need any mortar plasticisers or anything similar as you're not laying bricks.

When your back aches think of me.

 

[stihl260]

Build your 6x2 frame. Make sure the levels are spot on
Get a brick and beat down the loose soil, flatten it out as much as you can
Lay down your DPM
Mix your own concrete with a 4-1 mix (beg or borrow a cement mixer)
Get a 4x2 that goes end to end on your frame and level the concrete out.

You'll have the job done for next to nothing as a ton of ballast costs £40 rather than the ready mix which costs a few times that. Personally I wouldn't add anything to the mix unless it is very cold. You don't need any mortar plasticisers or anything similar as you're not laying bricks.

When your back aches think of me.

Munkey
This is V14 we are talking about here, i dont think cost saving is a consideration!
But the thought of him shoveling a ton of ballast, the old boy might have a heart attack,Lol
You know hes just going to use readymix because anything else is just too much hard work for him!:ur the man: