Ask The Trades - Print Page

Ask The Trades
https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Building Questions >> screed floor - estimating quantities https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1122938731 Message started by JohnD on Aug 2^nd, 2005, 12:25am

Title: screed floor - estimating quantities
Post by JohnD on Aug 2^nd, 2005, 12:25am

It occurs to me that rather than go back to my schoolboy maths (I failed the O level) someone might quickly and easily be able to work out the quantities of sand and cement I need for the screed floor I am about to lay.

The room is 11' by 5' 6" by 3 1/2 " deep. Any takers?

I make that about 335 by 168 by 8.89 cm, for those who think in metric. Don't rely on the conversion however - as I say, I failed maths!

Thanks - and thanks to Jerry for his help so far.

John D

Title: Re: screed floor - estimating quantities
Post by Dewy on Aug 2^nd, 2005, 5:27pm

Dont quote me on it as the only mortar or concrete I have made had been for home use but I always ignored the volume of the cement as it is used to bond the aggregate (sand and gravel) together so I always worked on the volume of agregate.
Centimetres are only used in schools because they are the closest to an inch on rulers.
The SI (system international) measures are millimetre, metre and kilometre.
So your figures should be 3.35m, 1.68m & .889m (.9 is better)
Multiply the three together to get 5.065 cubic metres.

Title: Re: screed floor - estimating quantities
Post by JerryD on Aug 2^nd, 2005, 6:11pm

Don't forget that a cubic metre of sand will not quite make a cubic metre of screed due to 'bulking' of sand when it is damp.

You may need as much as 5.5 - 6 cu/m of sharp sand to get 5 cu/m of screed.

Now the cement. A 25kg bag of cement will produce 0.06 cu/m of screed at 4:1 mix so for 5 cu/m you will need 83 bags.

Good luck!

btw, for volumes like this we always get Tilcon Ready mix screed. Screed is difficult and slow to mix in a conventional mixer. Ready mix screed has a retarder in it so you have all day to lay it. If you do decide to get Readymix screed you will need 5 cu/m as the bulking has been taken into account by the batching plant.

Title: Re: screed floor - estimating quantities
Post by woodsmith on Aug 2^nd, 2005, 6:23pm

JOHN STOPPPPPPPPPPPPPPPPPPPPPPPPPPP!!!!!

You need 0.5 cubic metres not 5 cubic metres

Hope you haven't order it for tomorrow :o

I hate metric so easy to get it wrong.

Title: Re: screed floor - estimating quantities
Post by JerryD on Aug 2^nd, 2005, 6:32pm

Bloody 'ell Dewy. What a cock up ;D

lol

Well spotted woody! :-*

(btw, it's always best to over-order slightly................ :P)

Title: Re: screed floor - estimating quantities
Post by Dewy on Aug 2^nd, 2005, 8:06pm

OOPS I had the decimal point on the .889 one place out.
It should have been .09m ::)
Geeze. I thought it sounded a lot. :o ;D

I hate metric as well.

Title: Re: screed floor - estimating quantities
Post by trowelhead on Aug 3^rd, 2005, 12:26am

Better to look at it than look for it! ;D ;D ;D ;D

Title: Re: screed floor - estimating quantities
Post by JohnD on Aug 3^rd, 2005, 11:04am

Only 83 bags? Thought it would have been more......

Thanks to all who responded!!! Order - just of ten bags - made - and a ton of sand. We'll see how close this enables me to get!!!!

Thanks

JohnD

Title: Re: screed floor - estimating quantities
Post by JerryD on Aug 3^rd, 2005, 7:37pm

If there's any left over I've got Dewy's address ;D

btw, just divide everything I said by 10 :-[

Erm.... 8.3 bags, ok get 10 then ;D

lol

Title: Re: screed floor - estimating quantities
Post by Dewy on Aug 3^rd, 2005, 8:23pm

wrote on Aug 3^rd, 2005, 7:37pm:

If there's any left over I've got Dewy's address ;D ;D

lol

I think I had better move to a new address. ;D

Title: Re: screed floor - estimating quantities
Post by JohnD on Aug 5^th, 2005, 1:02am

Seven sacks of cement did it - and there was some sand left over too - the floor sloped more than I realised! Result was not absolutely perfect but quite good enough!

Thanks to all who gave advice.

JohnD

Title: Re: screed floor - estimating quantities
Post by Dewy on Aug 5^th, 2005, 1:27am

Just as well woodsmith noticed my 'slight' mistake or you would have bought 70 sacks of cement John. lmao