i need to lay a new floor in my garage but i dont know how to work out how much sand and cement i need
the garage is 17feet long by 7 feet wide and really only needs to be 3" deep as is going on an existing base

can anyone help please

17*7*0.25 = 29.75 cubic feet which is 0.84 cubic metres.

seems very little to me?

Roughly;
17ft is about 5.5m.
7ft is about 2.5m
3" is about 0.075m

5.5 x 2.5 x 0.075 = roughly 1 cubic metre.

3" isnt a lot though. Depending on how the base is prepped (and for a garage probs not the same as a house) it may be subject to a little movement and could crack, unless you are putting a sheet of rebar under the floor.


Sorry - missed the bit about existing floor.

[Edited on 22/7/09 by DarrenW]

its not a huge amount but
i need to go and buy bags of cement and ton bags of sand
i just need to know how many of each to get delivered

im not very good at this sort of thing

concrete mix (not plain sand) tends to come in 1 ton bags anyway. All you add is the cement powder and water.



[Edited on 22/7/09 by Mr Whippy]

Builders merchants will advise qty's of each no probs. I cant remember the preferred mix for a floor.

quote:

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Originally posted by Mr Whippy
concrete mix (not plane sand) tends to come in 1 ton bags anyway. All you add is the cement powder and water.

[Edited on 22/7/09 by Mr Whippy]

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it is going on top of a concrete base (is on the site of an old outbuilding) but the base is below the level of my drive which we made deeper last year
i will add a membrane over the existsing site
and add some wire mesh (about 3mm thick)to the concrete to limit movement (we have used this before on the drive way and it hasnt cracked yet(fingers crossed )

quote:

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Originally posted by DarrenW
Roughly;
17ft is about 5.5m.
7ft is about 2.5m
3" is about 0.075m

5.5 x 2.5 x 0.075 = roughly 1 cubic metre.

3" isnt a lot though. Depending on how the base is prepped (and for a garage probs not the same as a house) it may be subject to a little movement and could crack, unless you are putting a sheet of rebar under the floor.

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thank you folks
im now going to get it all ordered

To give you a rough idea I laid a shed base last summer of 8' x 6'. I dug out 3 inches and filled with hardcore then laid concrete in a 4" deep frame over the top. No DP membrane or wire mesh as it's a simple garden shed base.

I used exactly 1 tonne bag of hardcore and 1 tonne bag of ballast. IIRC I got through 6-7 bags of cement powder too.

thanks nick205


ill get over to the merchants and get it ordered

If you have an old floor already down.

http://www.pureadhesion.co.uk/category/38/self-levelling-compound

You would be better off getting a mini mixer concrete truck to deliver it .. the cost difference is not that much and the quality will be loads better and loads quicker to do

I've been thinking of concreting the lane that leads to the garage at the back of my house, well my bit of the lane anyway. How deep would I have to make it and what is the typical cost of ready mixed concrete per cubic metre?

if you are going to mix your own a good mix for a garage floor would be 4:2:1 i.e. 4 parts gravel, 2 parts sharp sand and 1 part cement ( by volume)

Cheers

Mooky (City and Guilds in Concrete Technology)

quote:

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Originally posted by smart51
I've been thinking of concreting the lane that leads to the garage at the back of my house, well my bit of the lane anyway. How deep would I have to make it and what is the typical cost of ready mixed concrete per cubic metre?

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Just get cube of readymix, far easier and prob as cheap. Better quality too.

Having had a 8m x 3m x 15cm base put down this year I was advised not to mix myself as price would be higher and a lot more work.

A cube will be about 70 to 90 quid. Get a slag mix not a cement mix to give you working time.

I had mine power floated after and it is very smooth. The spirit level bubble does not go beyond the lines at any point.

quote:

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Originally posted by Nick Skidmore
I had mine power floated after and it is very smooth. The spirit level bubble does not go beyond the lines at any point.

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A metre is a lot to mix by hand, even with a mixer just throwing it in is a lot of work. I had to do it that way on the back as it is inaccessible and tipping the ready mix and barrowing it is a pain as well. I reckon a metre is about 2.5 tonnes so work your quantities out accordingly.

i managed to price my materials today but didnt manage to get across to order it (needed to work out complete cost before i ordered

anyway
ballast is £14 per ton
cement £3 per bag (25kg i think)
and the mixing can be done for free (arent brothers useful to have )