Concrete for shed foundations

DamoNolan · 12-04-2021 5:20pm #1

I'm building a shed and just wondering on costs of getting the concrete foundations premix and delivered or mixing it myself its a 4mx3m 400mm deep..I know it would take alot more time mixing it myself but just depends on costs..has anyone got any ideas of cost of concrete these days?

Calahonda52 · 12-04-2021 5:35pm

so the slab is 4*3 by .4: 4.8 m3, or 12 tonnes

DamoNolan · 12-04-2021 5:43pm

the slab is going to be 4 meters by 3 meters and 400mm deep

Bonzo Delaney · 12-04-2021 7:20pm

4.8m³ slab mixing yourself is about 100 mixes at 7 minutes a mix is about 12 hours non stop mixing 8 ton of gravel and 35 bags of cement plus a 1000 liters of water literally a ton of water. Material costs would be about the same about 450 -500e time wise hire a small dumper an you'll have it done in 2 hrs

mickdw · 12-04-2021 7:25pm

Sounds like complete overkill to be going 400mm deep on a shed 4m x 3m.
Perhaps 400 deep around outer edge but not all through.

martinr5232 · 12-04-2021 7:50pm

400mm is sixteen inches are you sure thats correct ??
What are you planning using the shed for ? If its just storage or garden shed 100 to 150mm would be plenty.
Either way id still go the readymix route if you can at all.

DamoNolan · 12-04-2021 7:50pm

Thats exactly wat I was thinking just around the edge and smaller depth for rest..im thinking of just ordering concrete save myself the hassle of mixing..whats the going rate for a m3 of concrete. Just standard stuff nothing special

martinr5232 · 12-04-2021 8:03pm

DamoNolan wrote:

Thats exactly wat I was thinking just around the edge and smaller depth for rest..im thinking of just ordering concrete save myself the hassle of mixing..whats the going rate for a m3 of concrete. Just standard stuff nothing special

About eighty euro.

DamoNolan · 12-04-2021 8:09pm

martinr5232 wrote: »

About eighty euro.

Ye that seems grand actually..saves the hassle of self mixing..how much do you reckon I would need..

DamoNolan · 12-04-2021 9:13pm

I forgot to mention this is for a block shed so is there a minimum depth I need to go

martinr5232 · 12-04-2021 9:54pm

DamoNolan wrote:

I forgot to mention this is for a block shed so is there a minimum depth I need to go

Anywhere between 100mm and 150mm depending on the ground you're building on.

Stihl waters · 12-04-2021 9:57pm

400 deep is nuts

vicwatson · 12-04-2021 10:32pm

Can i hop in here and ask if the likes of that would need a hardcore base and reinforcing mesh?

mickdw · 12-04-2021 10:49pm

vicwatson wrote: »

Can i hop in here and ask if the likes of that would need a hardcore base and reinforcing mesh?

What i generally do for a shed - 150 timber with 75 or 100 high timber stepped in on top to create a step.
Allow the full depth for 600 wide around outside and reduce to 150 for the rest.
4 12mm bars in base around outside and if you want a sheet of mesh near the top.

vicwatson · 13-04-2021 3:23pm

What N needed for this (where no cars etc on it, just a few people) someone said 30 N to me but from what I can see it wouldn’t need that strength ???

mickdw · 13-04-2021 3:29pm

Get 30

garv123 · 13-04-2021 4:52pm

is it going to be 4x3 x20 storys high? if so 400 should be ok.

vicwatson · 13-04-2021 6:20pm

mickdw wrote: »

Get 30

Really? With 10mil reinforcing bar and a depth of 100 mil concrete? Seems a lot overengineered no?

Lumen · 13-04-2021 6:27pm

Thoughts and prayers for whoever has to demolish this thing. :pac:

Stihl waters · 13-04-2021 9:53pm

Jesus christ the specs in here would bankrupt BAM

mickdw · 13-04-2021 10:03pm

Stihl waters wrote: »

Jesus christ the specs in here would bankrupt BAM

Vic watson isnt the op. I responded to his query without knowing what size the shed is.
My suggested design would be minimum required for any kind of decent blockwork shed.

[Deleted User] · 13-04-2021 10:09pm

Steeltech themselves recommend a 30N strip foundation 100-150 depth and 300 wide on top of 804. When the shed is installed, 25mm of blinding sand should be installed with a 2000 gauge DPM on top of it before pouring the 50mm finished floor.

The Mighty Quinn · 13-04-2021 11:16pm

mickdw wrote: »

Sounds like complete overkill to be going 400mm deep on a shed 4m x 3m.
Perhaps 400 deep around outer edge but not all through.

Agreed....
Recently finished a project where there was 11 metre high pallet racking in a warehouse and the slab was 225mm thick with A393.

Working on a water project at the moment where a tank holding 500 cubic metres of water has a 400mm thick concrete base.

I'd rethink your depth of concrete.

400mm sounds huuuge

vicwatson · 14-04-2021 10:34pm

Is €150 per cbm for 30n10 ott or in the ballpark?

Seems very expensive

sgarvan · 15-04-2021 8:51am

Recently laid a 4.5m x 3m x 4cm slab for a relative. Used 2cbm of readymix and it was €250 delivered. That included the truck staying there for 45mins and any more time was €15 per 15mins.

DamoNolan · 15-04-2021 9:27am

sgarvan wrote: »

Recently laid a 4.5m x 3m x 4cm slab for a relative. Used 2cbm of readymix and it was €250 delivered. That included the truck staying there for 45mins and any more time was €15 per 15mins.

Can I ask who you got the ready-mixed off?

vicwatson · 15-04-2021 9:59am

sgarvan wrote: »

Recently laid a 4.5m x 3m x 4cm slab for a relative. Used 2cbm of readymix and it was €250 delivered. That included the truck staying there for 45mins and any more time was €15 per 15mins.

Was it 30n10 ?

Included VAT?

Fine Cheers · 15-04-2021 10:07pm

Got my own slab for shed poured this week 2m x 3m 75mm thick increasing to 120mm (sloping ground). Put in dpm alright, no steel. Readymix the only way to go, lads barrowed it in and was all done in half an hour. Dont have finalised price yet as was piggybacking a neighbour who was doing a bigger pour. Had contemplated hiring a mixer and going DIY as I was waiting months but happy I held out.
Its the delivery / waiting charge you need to look out for, especially for smaller loads.

Lantus · 15-04-2021 11:56pm

If it were me id go with 100mm of sub base of compacted 804. A plastic sheet, Then 80mm to 100mm of concrete with a light mesh say 6mm. It adds a huge amount of strength to concrete. its probably a bit overkill but a good job you can walk away from.

About 1.2m3 of the good stuff. Assume a truck can get in or you have 3 barrows and strong men on hand to ferry it.

Timber frame it so you can run a timber over it to level it off.

https://youtu.be/H56eiJJ_FCY

Try here for a good video.

vicwatson · 16-04-2021 7:15am

Is a plastic sheet necessary for a slab that’ll be outdoors?

[Deleted User] · 16-04-2021 7:48am

vicwatson wrote: »

Is a plastic sheet necessary for a slab that’ll be outdoors?

Unless you want the interior walls of your shed to be soaking wet from rising damp, then yes.

Concrete for shed foundations

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