Mortar mix

[GSUK]

Hi,

I'm building a block wall as part of a shed. I've calculated I need about 12 sq m of block work. I found a calculator on line for amounts of sand and cement needed and it reckons I need just over 500kg of sand and six 25kg bags of cement. Does that sound right?

By my calculations that's approximately 3 lots of sand to 1 lot of cement. Is that a good mix?

I also need to set the foundations. Is it best to add agregate to the mortar? Do I need the same ratio of sand and cement too?

Thanks in advance for all advice.

Glenn

 

[bobloes]

A 3 to 1 mix is very strong. I have used 5 to 1 for a normal wall in a moderate climate. As for quantities I understand that a cubic metre of sand (other ingredients in proportion) is about right for 2000 concrete blocks.
I always buy ballast (ie aggregate and sand) and use a 4 to 1 mix with the cement.

 

[garyo]

I was planning on using a C20 mix for my trench fill foundations, which would be 6:1. Is that too weak? Am I better off with a C25 - 5:1?

Gary

 

[r896neo]

Just for the record a general purpose mortar mix would be 4:1 building sand to cement.

A general concrete mix is 3:2:1 Clean stone. sand, cement. Or if using all in ballast many recommend 6:1.

I am a bit confused, when you say you need to set the foundations do you mean pour them?If so then you use the concrete mix above not mortar with added stones.

For concrete 4:1 ballast to cement is very rich and unneccesarily expensive. 5:1 or even 6:1 is fine.

Garyo what is your found for? for a house or extension beef it up to the C25 but for small walls landscaping etc C20 is plenty

 

[bobloes]

Your right Neo I do use 5:1. Unable to divide 20 by 4!!

 

[garyo]

Yep mine are for foundations - C25 it is then...

 

[GSUK]

Thanks for the tips guys!

I'll post pictures once I get started


Cheers