Unknown Posted March 19, 2007 Share Posted March 19, 2007 HelloI am about to have some concreting done and have just received quotes for the materials from two local suppliers, I need enough materials to cover 7m3. The first supplier has suggested I need 25 sacks of cement, where as the other supplier suggests I need 50. Both use the same weight of sack. They have both suggested I need 7m3 of sand and gravel mixture.I'm going to have the materials delivered, so want to make sure I order the correct quantity. Does anyone know which of these suppliers is correct in their calculations, or is there a rule of thumb as to the ratio I need.Many thanks. Link to comment Share on other sites More sharing options...
avinalarf Posted March 19, 2007 Share Posted March 19, 2007 We used ready mix for 8m3 - it was about Euros 1,600 including a pump. It was just about the best money I've spent given the amount of hard labour it saved.My estimate would be 70 bags (35kg bags).Is this a bit like guess the weight of a cake or the number of jelly beans in the jar? Link to comment Share on other sites More sharing options...
dogwood Posted March 19, 2007 Share Posted March 19, 2007 HiNormaly you use about 10 sacks (35kg) per 1 cubic meter ballast (sand & stone)I would highly recomend ready mix, cost about 100€ per cubic meter.To mix it yourself ( approx) Ballast 30€ per mtr. cement10 x 5.50€ per sack = 85€ per cubic mtr. and a LOT of hard workIf you do the normal 4" /100mm deep you need 1m3 to do 10m2 so for your 7m2 a meter should be more than enough.Dont forget the reemesh.Just reread your post did i make an error? are you looking for 7m3 or 7m2? (cubic meter or square meter )Dogwood Link to comment Share on other sites More sharing options...
Jc Posted March 19, 2007 Share Posted March 19, 2007 Try www.concrete.org.uk Link to comment Share on other sites More sharing options...
Unknown Posted March 19, 2007 Author Share Posted March 19, 2007 7m3 Link to comment Share on other sites More sharing options...
Nearly Retired (I am now) Posted March 19, 2007 Share Posted March 19, 2007 You say you need 7 cubic metres of concrete. If my memory serves me correctly it's about 2.4 tonnes for each cubic metre, so you'll need to be mixing a weight of water, sand, aggregate and cement weighing in total around 16 - 17 tonnes. In England ( I don't know French camion sizes) you would almost certainly need 2 ready-mixed concrete trucks. I respectfully suggest that as it appears you don't mix concrete too often, please, please be prepared with a lot of friends. Link to comment Share on other sites More sharing options...
Chancer Posted March 19, 2007 Share Posted March 19, 2007 Bear in mind that when you mix concrete you get out a significantly smaller volume than that of the materials you put in, this is due to the lubricating efect of the cement and water.The following are official figures from Cement Calcia for dallage en beton.To mix 100 liters of concrete:5 seux de macon sable = 50 litres volume7 seux de macon gravier = 70 litres1 sac de ciment 35kg = 35 litreswater (dependant on wetness of sand) 17.5 litresSo incredibly for 172.5 litres of materials you get 100 liters out, or 120 litres of sand/stones (plus of course the cement) will give 100 litres of mix.When ordering materials (sand & stones) I always add 20% to my estimated volume.So for 7m3 I would use 3.5 m3 of sand, 4.9 (say 5m3) of gravel and 70 35kg sacks of cement, which around here works out at about 640 euros.If you can get readymix for 100 euros per cubic meter I would jump at it.Editted.After reading another post and your original request "to cover 7m3" I think that you have confused us all, and that you want to cover an area of 7m2 but dont specify the thickness rather than need to mix a volume of 7m3. Certainly the figures from your builders for sacs of cement seem to bear that out.If so then choose your thickness, multiply it (in meters) by the square area to give you the volume in m3 and use the figures above.You will probably not be able to order readymix at less than a 6 cubic meter load Link to comment Share on other sites More sharing options...
avinalarf Posted March 19, 2007 Share Posted March 19, 2007 I'm quite pleased with my estimate.Just fyi (old habits from the dark days of the office), the price of Euros 1,600 was for two lorries of the stuff - including pump and the wee fibres for added strength. Link to comment Share on other sites More sharing options...
Chris Head Posted March 19, 2007 Share Posted March 19, 2007 Dotty.Assume a weight of 1300kgs of material per cubic meter...7m3 = 9,100 kg of material, round up to be safe.If your mix is 7:1 and you can buy ballast (premixed sand and stone), then seven parts of that 9100kg will be ballast and one part cement. That would make 8,000kgs of ballast and 1100kgs of cement @ 35kg per bag = 32 bags.If you're having to buy sand and stone seperately then the mix will be 4:3:1 (sand stone cement), that would equate to 4550kg of sand, 3412kg of stone, and the same amount of cement, 32 bags. But round up to be safe.That's alot of graft. Link to comment Share on other sites More sharing options...
Pierre ZFP Posted March 19, 2007 Share Posted March 19, 2007 Readymix, in the UK at least, used to be OK with part loads. I had a neighbour that drove a mixer for them and said they would do it as quite often they had some left over on the truck while doing a big job and better to sell it than waste it. Wouldn't do less than 1 metre as I recall. Link to comment Share on other sites More sharing options...
P Posted March 19, 2007 Share Posted March 19, 2007 Mmm – mixing 7m3 of concrete. Now, if it was 1 or 2 then perhaps yes but, with an ordinary mixer there will be a large number of mixes (or perhaps the proposal was by hand). For 7m3 you are talking about readymix. However, you do need to be able to pour it quickly – the driver will not hang about. When I had 6m3 delivered the driver was telling me about a delivery he made to the front of a house. The owner was on his own with a wheelbarrow and wanted the driver to discharge a wheelbarrow full at a time so that he could wheel it in to the back garden – the driver merely emptied the load on to the street. In addition, you need to think about if there is too much. The driver may be able to get rid of it for you but, failing that, you may need to empty the excess onto plastic sheet spread it thinly and then break it up to dispose of it. Paul Link to comment Share on other sites More sharing options...
Chancer Posted March 19, 2007 Share Posted March 19, 2007 [quote user="Chris Head"]Dotty.Assume a weight of 1300kgs of material per cubic meter...7m3 = 9,100 kg of material, round up to be safe.If your mix is 7:1 and you can buy ballast (premixed sand and stone), then seven parts of that 9100kg will be ballast and one part cement. That would make 8,000kgs of ballast and 1100kgs of cement @ 35kg per bag = 32 bags.If you're having to buy sand and stone seperately then the mix will be 4:3:1 (sand stone cement), that would equate to 4550kg of sand, 3412kg of stone, and the same amount of cement, 32 bags. But round up to be safe.That's alot of graft.[/quote]ChrisI think that you are out by a factor of 2 on the cement and also out on the density of the materials.According to Calcia Im3 of sand is 1600kg moyenne and 1m3 of gravel is 1500kg moyenne, we cannot buy ready mixed ballast in my region.In any case the volume of mix will shrink as I have learnt to my cost several times.Using their figures of 350kg/m2 cement and also their fugures that 120 liters of sand and gravel (plus cement, not including) will make up 100 liters of finished mix using another (on average) 17.5 litres of water I still conclude70 off 35 bags of cement and just under 8.5 cubic metres of sand/gravel to fill a volume of 7m3The other ratios of cement they recommend are:250kg/m3 for unreinforced foundations350kg/m3 for reinforced foundations and lintels (400kg in mileu agressif)And between 250 and 500kg/m3 for enduit dependant on the support. Link to comment Share on other sites More sharing options...
dogwood Posted March 19, 2007 Share Posted March 19, 2007 Hi DottyAs you say you need 7m3 of concrete.Can you tell me what square meterage you are wanting to cover and what thickness? If it is just for a patio or standard flooring then 4" will be thick enough. If it is for foundations then it will need to be a lot thicker. and as the last post said the mix will be stronger.I can confirm my local supplier can deliver readymix for about 100€ per m3 (min delivery 1m3 max 6m3 per truck.)This is without pump, I you need one of these then that is extra.Yes it is about 10 sacs cement to 1 cube ballastDogwood Link to comment Share on other sites More sharing options...
Unknown Posted March 19, 2007 Author Share Posted March 19, 2007 Many thanks for all of your replies. I am well and truly confused now, but then again I usually am.[:D] Link to comment Share on other sites More sharing options...
dogwood Posted March 19, 2007 Share Posted March 19, 2007 Hi DottySorry we have confused you[:)]lets try this... What area are you trying to cover?Dogwood Link to comment Share on other sites More sharing options...
Chancer Posted March 19, 2007 Share Posted March 19, 2007 [quote user="dogwood"]I can confirm my local supplier can deliver readymix for about 100€ per m3 (min delivery 1m3 max 6m3 per truck.)[/quote] That price makes me feel really stupid for mixing all the concrete that I have over the last 2 years especially being able to order as little as 1m3.Back in England the only way that I could get less than 6m3 wash by paying a bent driver for what was referred to as "washings"! Link to comment Share on other sites More sharing options...
Unknown Posted March 19, 2007 Author Share Posted March 19, 2007 Sorry I don't have the dimensions, have just been given my orders to order 7m3. The area is an internal floor which slopes, so the concrete will be thicker one end than the other to get it level.Yes its a very big floor. Link to comment Share on other sites More sharing options...
dogwood Posted March 19, 2007 Share Posted March 19, 2007 J.R. That price makes me feel really stupid for mixing all the concrete that I have over the last 2 years especially being able to order as little as 1m3.Back in England the only way that I could get less than 6m3 wash by paying a bent driver for what was referred to as "washings"! Im with you on that one J.R. [:D] I mixed up a LOT of concrete by hand before I found I could get a 1 cube delivered for that price.Put a path in 2 weeks ago took me 45 mins total. By hand it would have taken ALL DAY[:(]Dotty If you are ordering 7 cubes of ballast you will need 70 bags (35kg)cement Dogwood Link to comment Share on other sites More sharing options...
Chancer Posted March 19, 2007 Share Posted March 19, 2007 Just to further antagonise myself I am going to check the price and minimum load with the depot which I have recently found, a french friend recently had a 6m3 dalle done, he said it was the minimum load and I'm sure that the price was much more than 100 euros per m3.This is the same friend that 3 years ago was showing me all the concrete (for a house, gite, stable and workshop) that he had had delivered for next to nothing! Link to comment Share on other sites More sharing options...
dogwood Posted March 19, 2007 Share Posted March 19, 2007 You got me wondering whether I had go it wrong so I went and checked the bill....[geek]I can only find the one for last year ( 17/11/2006) this was with 300kg cement mix. delivery to me is only 10km1m3 inc delivery 83€ plus tax 16.27€ = 99.27€ [:D]Not worth the effort of mixing by hand at that price!!DogwoodI would be interested what it costs in your area.[blink] Link to comment Share on other sites More sharing options...
Dave&Olive Posted March 19, 2007 Share Posted March 19, 2007 [quote user="Dotty "]Sorry I don't have the dimensions, have just been given my orders to order 7m3. The area is an internal floor which slopes, so the concrete will be thicker one end than the other to get it level.Yes its a very big floor.[/quote] hi ok that sounds, sorry but a stupid way to go .. level the floor first with 0-31.5 bind it with sand and a dpc layer, then just use 4" of concrete on top !!! you can cover a floor of 10mtrs x 7mtrs x 10cm thick with 7m3 of concrete ,and if your floor is this size and you do it in one hit you really need to fit an expansion gap .the floor will expand and push the walls out when hot ..or lift in the middle ..the Sp. G of concrete is 2.4 so 1 mt3 is 2.4 metric tonnes or 24 standard barrow loads . the mix should be 5 parts sand 7 parts gravel , 2 parts cement . so if you use mellange ( a pre mix of sand and gravel ) mix it 6 to 1 . A standard size brico mixer will take 12 shovel fulls of mellange and 2 cement ,and will then just over fill a barrow or 1 mix ( depending if its dryish or wet)this is uk ... the most a ready mix lorry can carry is 6m3 so if you order this amount it works out cheap ( the price v delivery ) so for 7m3 you need 2 .ok I am not a builder but my son is I was his navvy for 10years at weak ends to fund my life here and to gain the know how .don`t do it go for ready mix just my opinion but good luck Dave Link to comment Share on other sites More sharing options...
Chancer Posted March 19, 2007 Share Posted March 19, 2007 Well put Dave.They were the proportions that I always used to use in the UK, but it has been some years and because we cannot get all in ballast here I have been using the calcia recommendations but did think that I was using more cement than before, but as it has been generally for reinforced footings, lintles and structural floor slabs I preferred to play safe.I would like to add that the shovel full's that you quote are fine for my beloved british shovel but a French one is much smaller and therefore less tiring and strainfull (is that a word?) to use.They generally measure the mix in seau's (buckets) which are 10 litre volume, i.e 7 buckets of gravel, 5 of sand and a 35kg bag of cement in one go in a big mixer fills a big barrow. Link to comment Share on other sites More sharing options...
jacqui Posted March 19, 2007 Share Posted March 19, 2007 Hi everyone I have been following this thread and I really need ready mix to level a floor- can you please tell me the french term for ready mix concrete. We are in the Haute Vienne by Magnac Laval if anyone has any suppliers I would be most gratefulThanksJacqui Link to comment Share on other sites More sharing options...
oglefakes Posted March 20, 2007 Share Posted March 20, 2007 [quote user="jacqui"]Hi everyone I have been following this thread and I really need ready mix to level a floor- can you please tell me the french term for ready mix concrete. We are in the Haute Vienne by Magnac Laval if anyone has any suppliers I would be most gratefulThanksJacqui[/quote]You might be better of with self leveling compound. It's like really runny mortar more than concrete, but adheres well and dries with a concrete finish.As for the 'self mixing' of concrete, please be aware of 'Cold joints', not leftover sunday roast, but the situation where concrete starts to dry and doesn't really bond well when the next wheelbarrow load is dumped next to it. Instead of a large monolithic slab, you get something more like fish scales. i.e. each scale represents a load of concrete and they do not really bond. This can be an issue in hot weather and with large areas, but not such an issue with say, foundations for garden walls etc.cheers Link to comment Share on other sites More sharing options...
Pierre ZFP Posted March 20, 2007 Share Posted March 20, 2007 [quote user="jacqui"]Hi everyone I have been following this thread and I really need ready mix to level a floor- can you please tell me the french term for ready mix concrete. We are in the Haute Vienne by Magnac Laval if anyone has any suppliers I would be most gratefulThanksJacqui[/quote]french term for ready mix concrete = le béton prêt à l'emploiApparently Leroy Merlin do it but I don't know what it costs Link to comment Share on other sites More sharing options...
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