Laying dense blocks

[Millwright]

Hello chaps, have a small project at home to do where I'll be laying a few courses of dense blocks. Now, as these aren't as light as aerated blocks, what is the best way to ensure the weight of the block doesn't squish the mortar out and away, unlike with the light weight of a regular brick?

Thanks.

 

[stuart45]

As long as the mortar is OK and the blocks aren't soaking wet you won't have a problem.

 

[Millwright]

I usually knock up a 1 part cement, 2 parts building sand plus mortar additive, to make the mortar 'ok', I guess I just need to add less water to make the mix stiffer?

 

[kingandy2nd]

That’s a very strong mix. 4 or 5 parts sand will be fine

 

[stuart45]

Doesn't need to be too stiff. Standard mortar is fine.

 

[^woody^]

The thing is not to drop the blocks, but gently place them on top of the bed, then a slight press or gentle tap with a lump hammer

Its got nothing to do with the mortar strength (although 2:1 is way too strong), more to do with the consistency of the mortar (rather than how wet it is) - so use an admix.

 

[noseall]

more to do with the consistency of the mortar (rather than how wet it is) - so use an admix.

Correct.

Aged mortar is best, i.e. a mix that has stood for a short while. We may run in with a barrow of wet gear then drop onto a corner and lay heavy blocks, with what's left say after break. Mortar gets better throughout the day as the drum leftovers adds goodness to the next mix. The first mix of the day is always the poorest.

 

[23vc]

Mortar gets better throughout the day as the drum leftovers adds goodness to the next mix. The first mix of the day is always the poorest.

I’ve never experienced that as I’ll always clean the mixer after each mix, due to being paranoid about not being able to get it clean if the old bits get dry after the couple of hours it takes me to lay a drum full. But then again I’m on my Todd most of the time and work at a leisurely pace