Do I fill hollow blocks with mortar or concrete?

[nuzuki]

Im building a wall for a garage. The blocks are 6inch hollows. Do I fill them with concrete or mortar? I have a feeling its concrete.

Also do I need to do all the filling at once or can it be done in stages?

Thanks for your help

 

[John D v2.0]

I'm only a diy but I'd do concrete, it's cheaper because of less cement, less shrinkage, and the holes should be big enough to take the aggravated.

 

[tomfe]

None? Why do you need concrete in them?

 

[nuzuki]

The wall is 10m long so I was advised to do 6inch hollows filled if I wanted to avoid building peers. Im guessing if I put rebar in them and drill down into the slab then I can fill them in stages.

Only problem is switching from concrete to mortar with my mixer means the odd few stones get into the mortar mix.

 

[tony1851]

Wouldnt it have been easier to build one or two piers in brick, rather than fill in 10m of hollow blocks?

 

[^woody^]

Fill them with air.

 

[nuzuki]

It could of been tony if I was any good at brickwork but as im not i'll go with the filling method. Im just a DIYer so try not to get too much out of my depth with these jobs. The slab is pretty thick 6-12inches and has reinforcing mesh and footings trench so it will be able to take the weight.

I have remeasured the wall and it is closer to 8.5metres if that makes any difference.

 

[tomfe]

If your joist height is under 2.4m then I would not bother.