Optimal bricklaying mix

[macadonald]

Hi guys,

Very sorry as I know this is a frequently asked question. After a rushed few days to get everything ready for the brick layers which start tomorrow, I'm ready and excited.

So that I can keep an eye on them and not get messed around in any way, what is the ideal sand, cement, plasticiser ratio for laying bricks and blocks?

Many thanks

Mac

 

[^woody^]

There is not one. It depends on the sand and the bricks and blocks. It's not a science

 

[macadonald]

Thanks woody, I accept that as an answer

Will let e guys get on with it, but will hope for a 3:1 for below ground and a 4 or 5:1 for the above ground works.

 

[stuart45]

This is the NHBC guidlines for mortar.

Untitled

• stuart45
• 2 May 2010
• 2

 

[RonnyRaygun]

Basically, the stronger you make the mortar, the stronger you make the wall.
But the mortar only needs to be strong enough in combination with your bricks/blocks to carry the loads applied. Where loads are high - such as underneath beams - a stronger mortar might be required, possibly with stronger bricks/blocks too.

1:5to6 is given in BS5628 and has a compressive strength of 4N/mm2, and is strong enough for most timber floored domestic properties.

 

[^woody^]

Basically, the stronger you make the mortar, the stronger you make the wall.

And the more inflexible and less tolerant to normal movement.

What's "stronger" .... a wall with cracks and debonded mortar, or one without?

I suppose it depends whether the wall is a in railway bridge or a front room

 

[RonnyRaygun]

Basically, the stronger you make the mortar, the stronger you make the wall.

And the more inflexible and less tolerant to normal movement.

What's "stronger" .... a wall with cracks and debonded mortar, or one without?

I suppose it depends whether the wall is a in railway bridge or a front room

Yeah, I wouldn't be using a 1:3 mix as standard in a domestic situation, but then a well designed modern masonry building doesn't need to be as flexible as an older one, as foundations should be of a suitable depth, and if required bed joint reinforcement, or movement joints (or both) should have been installed.

The stronger mixes are really only for heavily loaded piers or sections of wall.

 

[^woody^]

I think there are literally so many variables that the text book guides are a bit meaningless, and make it irrelevant. Anywhere between 1:4 and 1:9, but you wont ever know unless you use some impractical site testing and monitoring

You are just so reliant on the gangs competence in general.

I bet you wont see them mixing two different mixes for the brickwork and blockwork though

 

[theoldun]

Looks like the armchair task force are having an away day.
Regards theoldballerinahoddy.

 

[^woody^]

Come on then granddad, grace us with your wisdom on the optimal mix and plasticiser for the OP.

And please don't come back with a poxy 1:4 for brickwork and 1:6 for blockwork

 

[theoldun]

Come on then granddad, grace us with your wisdom on the optimal mix and plasticiser for the OP.

And please don't come back with a poxy 1:4 for brickwork and 1:6 for blockwork

One of the few pleasures left to us in life is winding people up. Never thought we would get you to bite woody.
Our mix is very simple.
Five/three and half mixer with the inlet side on the right when viewed from the engine. Water butt 12 metres away from the mixer so that additional air is entrained in the water on the walk back. 25 shovels of sand from a full throat shovel, 25kg dust and two egg cups of Feb Admix Powder Not liquid. Egg cups to be medium size. Water content with us, is very hit and miss. Depends on what way the wind is blowing and whether the hose pipe is froze up
If you pass this mix on to any future bricklayers you employ, then you will be very pleased with the results.
Regards Grandaddy

 

[^woody^]

And you use the same old mix to every type of brick or block, in every type of weather, and for loamy or sharper sand?

 

[noseall]

And you use the same old mix for loamy or sharper sand?

Add or retract water 'to taste'.