How to anchor cinder blocks to exisiting slab for a bench seat?

[MamaCass]

Hi There, 

I am using 190x190x390 cinder blocks to build a bench seat that will be topped off with inset 18mm ply and a piece of custom foam. I am only building it 2 blocks high and then capping it off and putting a foam cushion on top.  Total cinder block + cap Height is 420mm (not including cushion).

I will be laying the blocks on an existing concrete slab. How do i anchor the blocks to the slab?  Is morter alone enough? I was also going to construct a internal frame using 900 x 45 on the inside for added stability and so there is a platform to put the cushion on. This will prevent the blocks from falling inwards but not outwards.  Can i bolt the timber frame to the blocks from inside?  I have a tendancy to over engineer things because i have 3 small children, is this overkill? 

Also, I was considering adding another section that would be 4 blocks height for the BBQ and some bench seating, for this add on the blocks will be much higher, perhaps 800mm high including caps. How should i ensure it is stable? 

Please see my design images, they are images of the blocks roughly arranged WITHOUT caps. This is not the final arrangement but it gives you an idea of the basic shape.  Its a very wide daybed, bench seating and then staggers up to become an L shaped bench top height for BBQ and outdoor cooking space. 

Lastly, I wanted to render is white to have that Spanish look (I have included lots of inspiration shots), can you please assist me with what products i might need to achive that look and can i render on to wood or ply or does that need a primer first?

THANK YOU SO MUCH!

[MamaCass]

Ah, I think my terminology is wrong but we are on the same page. Rather than both pieces of wood shaking hands, I only intend to cut a lap in the 90 x 90 post and then rest the LVL on  and in that lap.

The LVL is only 42mm x 240mm so I can’t afford to cut into it because it would weaken it too much (I assume). 

[EricL]

Hello @MamaCass 

Cutting the 90x90 and having the LVL sit on the post will transfer the load to the post. If you are fixing it with a nut and bolt configuration it's definitely a plus as the nut and bolt will not be carrying all the load of the assembly. 

Eric