outside block wall

[martin29e]

hi all im looking at building a single skin block wall it will be 12 block long and 4 high what im trying to find out is the amount of mortar mix i need i was looking at trying to use the ready mixed bags from totem it does about 25 house bricks it does't say how many blocks or would it be cheaper buying bags of sand and cement if so how many bags of each would i need please i will be useing a 1-5 mix

many thanks

 

[PrenticeBoyofDerry]

It should do about twice as many concrete blocks 440x215x100, compared to your standard red house brick.
What is wall being used for, I'd consider putting a frost protective admixture in mix, if you are considering doing this soon.
I believe current recomended working temp is 4 degrees c and rising.

 

[martin29e]

just for a boundary wall not going to do it till may time just trying to work out the cost of it

 

[PrenticeBoyofDerry]

usually you'll find that sand and cement bought separate will be cheaper than buying premixed.
Is the wall replacing one and will it need footings and is it to used as a retaining wall?
These a considerations for materials you will need as your footings could well need to be 9-12 inch wide and 4-6 inch deep for the whole length of wall.

 

[martin29e]

no its a new wall so will need a footing i was thinking of a footing about 12 ins wide by 6 in deep and no it not being used as a retaining wall

 

[PrenticeBoyofDerry]

Footings plenty big enough then, you will need to use a blended mix of sand/limestone and gravel with the cement for the footings.
This will give you a strong solid base.

 

[martin29e]

i was thinking for the wall i would need about 9 bags of cement and 20 bags of sand does that sound about right as for the footing i have no ideas the bags i need

 

[PrenticeBoyofDerry]

Bit excessive on sand and cements, I'd say 3 bags Cement 25kg and 9 bags of sand (25kg)
This little tool may help you.
http://www.source4me.co.uk/calculate_brick_block_mortar.php

 

[martin29e]

ok many thanks for the help any idea how many bags of ach i would need fot the footing sorry to be a pain

 

[PrenticeBoyofDerry]

your footings approx.
3-4 bags cement
one third to half tonne of ballast or blended mix of limestone/gravel

I am assuming your wall is 5 metres long.

 

[martin29e]

yep 5 meters long 1 meter high

 

[jm2000]

Hi , i just noticed this thread, not to good with quants. but i had a quick add up dependant on the mix 5/1 ratio id say 10 bags sand and 3 cement. for the wall, dont forget a little feb to help plasticise the mix.

But my big concern was the length of the wall and no support

5 meters , thats fine but its going to be a little weak, if as you stated its single skin.
I think your going to want at least 3 pillars in that. 1 at either end and one in the middle.

And also, is the metre high just a rough guide, if it is 4 course its 900mm if its the metre you want then its 4.5courses and with the pillar at either end and the middle then you'd need 68 block. most packs from builders suppliers of 100mm 7n block come in packs of 72.

 

[martin29e]

yep the hight is just a rough guide it may be a little higher. are you counting 2 blocks wide for the pillar supports ie the wall runing across from let to right and have the pillar supports runing in line with your self and haveing them tie in to the wall

 

[jm2000]

I take it it a straight wall.

basically you are going to lay 12 blocks in a line, behind block 1 6 and 12 you would lay another block to form a pillar. Tie these across with some small cavity ties and or bond every other course


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