Can I lay a finishing row of 4N aircrete blocks on top of 2.9N block wall?

[kay4ng]

Hi everyone, thanks for previous magnificent help.
I am about to finish my 3 x 3m rear extension. Only 2 rows of block remaining to go up before the roof is loaded. Being using 2.9N aircrete blocks of 440x215x215mm for my solid wall.

[ Can't seem to find 2.9N blocks in the market. They continue sending me 4N which I rejected twice but now accepted the last load -just fed up].

I am wondering if I can lay these 4N blocks as the last row on top of the 2.9N block wall. Also I plan to finish this wall by constructing a 100mm thick bond beam made up of concrete (RC30) and rebars whose Newton wt must be (?) more than 2.9N.

Read more: https://www.diynot.com/diy/conversations/aircrete-blocks.34657/#ixzz66OwJU6rJ

 

[John D v2.0]

The N is actually a measure of the pressure they can withstand, not the weight. It's Newton per mm square.
You can lay them in whatever order as long as they are strong enough (they will be) and they meet the thermal requirements overall ( should do)
Id be more concerned about the concrete beam as the u value will be getting towards the double figures, but in assuming the whole wall will be external insulated?

 

[kay4ng]

Thanks John D V2.0. The external wall is being rendered as I build up (so as to not use scaffolding) to a thickness of 30mm using chicken wire mesh /mortar and last coat SBR bonding of white 0.2mm stone (dash). Also the inside is being rendered with 12mm mortar and will be finally covered with 25mm thick celotex insulation.

Emm John D V2.0, what do u mean about laying 4N and 2.9N in any order? Do u mean I can even lay for e.g. an alternating row of 2.9N and then 4N, then 2.9N and so on- just curious?

 

[John D v2.0]

Emm John D V2.0, what do u mean about laying 4N and 2.9N in any order? Do u mean I can even lay for e.g. an alternating row of 2.9N and then 4N, then 2.9N and so on- just curious?

I'm no builder but what are you expecting might happen? It certainly won't fall down, but you'd have to check all the other performance standards if you're relying on it for insulation or something.
Also you have to be a bit more careful with render as those blocks are not as stable in terms of cracking as concrete. But it sounds like you have plenty of mesh in there, and I'm not a rendering expert of course.

 

[kay4ng]

Yea, very careful -used 5:1 sand:cement ratio thru out over wire mesh wrap which is very necessary to prevent cracking in aircrete. Thanks again for replying me a 2nd time. Goodnight for now till next learning opportunity crops up.