Concrete, mix myself or get a truck?

Seve OB

What is the advice here please?
I have a trench nearly dug out and which will be finished in the next few days. I’m building a rising wall in it for foundations for a garden workshop. See other thread.

Anyway just looking at my options for the concrete to go into it. About a foot wide and 10 inches deep. 3 meters by 4 meters rectangle.

Am I correct in saying it should be 1 part cement, 2 parts sand and 3 parts gravel? How much water? Will stick some rebar into it also. How much though? Is one bar all the way around sufficient or do I need more? How big should the bar be, I see loads from 10mm to 22mm.

Then the big question, mix myself or get ready mix?

Back garden with no access so would be wheelbarrow job. I don’t really have anyone who can commit to helping. I’m not sure how the trucks work, do they give you a time limit? What kind of hours do they deliver? Are weekends/sundays an option?

I can get a lend of a mixer, I know it would take me a full day to do myself but it’s surely a fairly handy task unlike the back breaking work of digging the trench.

If I do mix myself, I’ve been looking at calculators and have some different answers to what I need so anyone care to work it out for me please?

Thanks

Calahonda52

what width is the wall?
what height is the wall of the shed?
Any provision for piers?
what depth is the footing going to be?
.
the math is easy enough
perimeter is 3+3+4+4 = 14m
say the footing is 300 mm wide and 300 deep or .3m and .3 m
so 14 by .3 by .3 = 1.25 m3 but that allows for no waste and assumes a perfect trench:D

At that level of concrete truck price will be expensive

Seve OB

I will be going 1 block on the flat and 1 4 inch wide block on top of that, so an L shape.

Shed will be timber frame (so no piers) 10 foot tall

Yes I was getting close to those numbers, might just go 10 inches deep instead of 12... ground is quite hard where I've gone down to.

So you think truck will be expensive because I'm not getting enough to make it cost effective?

what about the mix ratio I quoted?
to get 1.2m3 how much of each would I need?

Mac-Chops

Assuming you've done your research on footing width/depth but I've just done something fairly similar recently for a hollow block wall.
I make that out at just over 1m3 (Say 1.2m3) needed which is very doable yourself with a mixer, a barrow and good size shovel.
Agreed handier than digging a trench but barrowing in the aggregate and bags of cement and then shovelling in to mixer will have the back fairly burning too.

Get a couple of ton sacks of gravel from your builders providers, check it ideally has sand in it ready for concrete such as here.
You might only use half the 2nd bag but still cheaper than buying and lugging a heap of 25kg bags.
Aim for adding about half water to cement but the sand/gravel will likely be wet itself so add water gradually in the mixer. Look up a few slump test videos to get an idea of the consistency you're after.

5:1 gravel/sand to cement as you've mentioned would be plenty.
You'd need a good 20 mixes depending on your "about" dimensions.
So say 15 bags of cement, or go more if buying in bulk and you're laying blocks / making mortar.

In terms of reinforcement, 10mm bars more than enough. If you're buying this anyway just get some wire mesh instead and cut it up if you can get your hands on a grinder. 1 layer would be fine and drop it in mid concrete layers or use some spacers.

I had a quick look at your other thread and see your garden is sloped so assuming your trench is level/stepped already or you will need to add in some steps. Otherwise, this will affect your depth dimension as you'll obviously need more concrete at the higher ends.

Seve OB

thanks Mac Chops
yes there is a slope on the garden but the trench will be level.
have a grinder (somewhere) so might go for the mesh

That sack of gravel you liked there you mentioned already has sand in it, so I wouldn't need to add in any extra sand?

dzer2

Seve OB wrote: »

thanks Mac Chops
yes there is a slope on the garden but the trench will be level.
have a grinder (somewhere) so might go for the mesh

That sack of gravel you liked there you mentioned already has sand in it, so I wouldn't need to add in any extra sand?

Depends on where you are

Quarries around me would mix you that amount but you would want a trailer to bring it home in.

Mac-Chops

Seve OB wrote: »

thanks Mac Chops
yes there is a slope on the garden but the trench will be level.
have a grinder (somewhere) so might go for the mesh

That sack of gravel you liked there you mentioned already has sand in it, so I wouldn't need to add in any extra sand?

Yes, that's the idea to save you the hassle of mixing from multiple bags.

If you'll have use for the sand making mortar for blocks then you could go down that road and split again 2:3 for sand/clean gravel but for the quantities involved it's not worth the cost/effort trade off I reckon.

Seve OB

Mac-Chops wrote: »

Yes, that's the idea to save you the hassle of mixing from multiple bags.

If you'll have use for the sand making mortar for blocks then you could go down that road and split again 2:3 for sand/clean gravel but for the quantities involved it's not worth the cost/effort trade off I reckon.

Thanks. I’ll need sand to set the blocks. I laid some blocks many, many years ago and can’t remember exactly. But maybe a 3:1 sand cement mix?

I’ll also need sand for a patio area I will be finishing off…… but that be after this job !

Was going to order from brooks. Grange you linked there are a good bit more expensive for the blocks. But im not sure if brooks gravel though is a sand mix. I suppose I’ll bell them.

Mac-Chops

Seve OB wrote: »

Thanks. I’ll need sand to set the blocks. I laid some blocks many, many years ago and can’t remember exactly. But maybe a 3:1 sand cement mix?

I’ll also need sand for a patio area I will be finishing off…… but that be after this job !

Was going to order from brooks. Grange you linked there are a good bit more expensive for the blocks. But im not sure if brooks gravel though is a sand mix. I suppose I’ll bell them.

I'd still go batched gravel/sand if you can get it. By right you should probably have a sharp sand for concrete and a finer mortar sand for blocks anyway.

I used the same 5:1 sand/cement mix for mortar through advice from a brickie mate and just added some plasticizer, worked out fine.

Grange are near me and one of the more competitive ones on delivery and are quick so just factor that in. Roadstone direct for blocks/sand worth a look too but they charge €55 for delivery, similar for Brooks I think.

the_pen_turner

cheaper to get the truck . bags of cement are expensive.
i would go 4 to 1 rather than 5 to 1

ring your local providers and let them know what you want. if you can find one of the truck drivers living locally you can get them to bring it to you on top of a smaller load
i have done this a few times on jobs where i was there all week anyway so could drop everything and pour that small bit whenever he came

Seve OB

the_pen_turner wrote: »

cheaper to get the truck . bags of cement are expensive.
i would go 4 to 1 rather than 5 to 1

ring your local providers and let them know what you want. if you can find one of the truck drivers living locally you can get them to bring it to you on top of a smaller load
i have done this a few times on jobs where i was there all week anyway so could drop everything and pour that small bit whenever he came

rang one place.
€270
30 minutes waiting

i think it will be cheaper and easier (less stressful about having people lined up to help etc) to do it myself

the_pen_turner

Seve OB wrote: »

rang one place.
€270
30 minutes waiting

i think it will be cheaper and easier (less stressful about having people lined up to help etc) to do it myself

Jesus thata dear. Last time i did it it only cost 150 I think

Calahonda52

Seve OB wrote: »

I will be going 1 block on the flat and 1 4 inch wide block on top of that, so an L shape.

Shed will be timber frame (so no piers) 10 foot tall

whats with the block on flat and then on edge?
whats the fixing detail of shed to block?

Lantus

the_pen_turner wrote: »

Jesus thata dear. Last time i did it it only cost 150 I think

One cube is the least you can get delivered. The cost only increases a little as you buy more. 6 cube may be 600.

If the shed is not accessible then it's wheelbarrow derby or a pump. I'd say for what you are doing a mixer is better overall in terms of cost. Just look up mix ratios and try to be consistent. Lay a mesh about 50mm off the bottom and in from the sides, don't squish it into the dirt so it's encased and won't corrode....as fast..

DublinDilbert

Do you have the blocks already? If you don't have the blocks, why not pour a complete slab, which will be the foundation for the walls and the internal floor? Put some reinforcing mesh into the slab.

Mobile concrete pump is €300-€350, allow the same for the concrete depending on the size. Get some used scaffold boards as the formwork, you can get these for €5 each. Also while you are getting it delivered, do you need to put in a path in front of the shed, as this could be poured too.

I did similar last year, poured slab, path/ramp, and foundations for a greenhouse. We had 3 people on wheelbarrows so didn't need the pump, but we got a lot done for €300.

Seve OB

DublinDilbert wrote: »

Do you have the blocks already? If you don't have the blocks, why not pour a complete slab, which will be the foundation for the walls and the internal floor? Put some reinforcing mesh into the slab.

Mobile concrete pump is €300-€350, allow the same for the concrete depending on the size. Get some used scaffold boards as the formwork, you can get these for €5 each. Also while you are getting it delivered, do you need to put in a path in front of the shed, as this could be poured too.

I did similar last year, poured slab, path/ramp, and foundations for a greenhouse. We had 3 people on wheelbarrows so didn't need the pump, but we got a lot done for €300.

No I don’t have the blocks
You need to build a rising wall and then put insulation in it before laying the slab

I’ve ordered the gravel and cement etc for just over €200 and will mix myself so no wheelbarrow derby!!!!. Thanks for the tips guys

tDw6u1bj

Seve OB wrote: »

I’ve ordered the gravel and cement etc for just over €200 and will mix myself so no wheelbarrow derby!!!!. Thanks for the tips guys

Unless you hate yourself I'd cancel that and get the readymix.

Rent a mini-dumper for the day and carrying it won't be a problem.

The cost should only be a fraction higher

Seve OB

tDw6u1bj wrote: »

Unless you hate yourself I'd cancel that and get the readymix.

Rent a mini-dumper for the day and carrying it won't be a problem.

The cost should only be a fraction higher

Apart from the cost to rent a mini dumper, the access at the side of the house is only 80cm wide so I don’t think it would be an option

Metric Tensor

200 for the materials vs 270 for the ready-mix?

If you have access to two other lads and a 3 wheelbarrows I can't see how mixing it yourself would ever be worth the 70 quid saving.

If you're on your own with no help then I can see why you might mix it yourself for time reasons.

tDw6u1bj

Seve OB wrote: »

Apart from the cost to rent a mini dumper, the access at the side of the house is only 80cm wide so I don’t think it would be an option

Mini dumper is 700mm wide - designed for fitting through doorways. €150 for the day but I expect the readymix would work out cheaper. edit - missed the quote earlier. ring around, with that price and wait I don't think they're interested in customers.

2 people with a mixer will lash that out of it.

Furze99

DublinDilbert wrote: »

Do you have the blocks already? If you don't have the blocks, why not pour a complete slab, which will be the foundation for the walls and the internal floor? Put some reinforcing mesh into the slab.

Mobile concrete pump is €300-€350, allow the same for the concrete depending on the size. Get some used scaffold boards as the formwork, you can get these for €5 each. Also while you are getting it delivered, do you need to put in a path in front of the shed, as this could be poured too.

I did similar last year, poured slab, path/ramp, and foundations for a greenhouse. We had 3 people on wheelbarrows so didn't need the pump, but we got a lot done for €300.

That's what I'd do and have done - slab foundation with mesh rebar and get the ready mix in. Wheelbarrowing is a lot easier than mixing by hand and you have a consistent batch of mix, which sets as one unit. The leveled slab is perfect for the workshop floor.

1874

I got concrete pumped in for a foundation slightly bigger than that. Probably cost me, cant recal, but I dont think it was an arm and a leg, but it was worth it as the place was a mess and it would have been a pain using a wheel barrow, I don't think it was even practical.
I'd dug it out and laid some re-bar and interconnected it, for the sake of the hassle and my back I just paid whatever extra it was.

maxpet

Just wondering in the end did you mix it yourself or get the pre-mix???

Seve OB

Mixed myself

Had some help lined up for last Sunday but the weather went against me and I had to freeze plans. Got stuck in on Tuesday. Was on my own. Lost count, but probably ended up doing between 25 & 30 mixes. Hard work but really enjoyed it and happy with the result. Will hopefully get laying the blocks during the week

Pinoy adventure

Where are you located ?

We used a Dublin based crew and concrete deliver was

1 ton =€100

2ton =€160

the lads were great and gave as much time as needed with wheelbarrow

Seve OB

now ya tell me!!