Bonding 100mm to 75mm cavity internal wall

[baker332]

HI,

In the process of bricking up the internal wall for the cavity gap from old (75mm cavity) to new (100mm cavity extension), what's the best approach here? Step/stagger the bricks in straight whilst following either the 75mm or 100mm cavity or slightly angle the blocks so that they align with one another?

My build shall have a steel resting on the block work therefore needs to be strong, with padstone.

The drawings do not hold this detail I'm after.

Thanks

 

[noseall]

HI,

In the process of bricking up the internal wall for the cavity gap from old (75mm cavity) to new (100mm cavity extension), what's the best approach here? Step/stagger the bricks in straight whilst following either the 75mm or 100mm cavity or slightly angle the blocks so that they align with one another?

My build shall have a steel resting on the block work therefore needs to be strong, with padstone.

The drawings do not hold this detail I'm after.

Thanks

Have a 25mm step-out

 

[Wayners]

I had that at home. A step. 75mm to 100mm

I put spring line down and screws in wall following sting line to get it straight. The screws acted as a stop so board rested on

 

[baker332]

Hi both, thanks for feedback. Just want to be clear, when we talk about a step, we are literally talking the bricks not aligning perfectly with a step sounds obvious?

Is there anything wrong with slightly angling the bricks to make it flush?

If you step this out and use a running brick bond pattern, surely the step is all over the wall as the bricks meet? I'd like to know the strongest and best method as a steel shall be sitting at the top of this.

Thanks

 

[cdbe]

I was under the impression that toothing in was not recommended these days (if that's your intention) and that wall starters were supposed to be used. I suppose the slanting in would be better for the padstone to sit on - maybe check with you engineer although I doubt a few cm less bearing would be an issue.

 

[baker332]

The intention was to tooth in the blocks as it makes the wall stronger and work together better, especially when a steel is placed on top of the wall.

It's possible I guess that wall starters could be used and the loads would still spread/distribute evenly.

However the question is that, should the wall be stepped how is that bonded? Or is it possible to ever to slightly angle the blocks without having a detrimental effect to the structure and strength of the internal thermalite wall.

 

[cdbe]

I understand the idea of toothing in, however any minute settlement of the new foundation Vs the original will mean that the blocks will just crack in a vertical line from top to bottom, then you have nothing holding the two walls together. Your stepping in or sloping in will make no appreciable difference to the strength of the wall, the only issue I can see is that your padstone will (if it straddles the join) have a bit of overhang where it's not bearing onto masonry, but again, hardly likely to make a difference - but if in doubt ask your engineer, who will have calculated the bearing.

 

[baker332]

Engineer is MIA cdbe hence asking for advice on here.

If anyone else has anything to offer please let me know, thanks.

 

[noseall]

If there is an importance that the two are to be fully bonded, then it could mean a rebuild in any case.
What did the engineer suggest?

 

[^woody^]

Post a plan or something, I can't make head or tails of it.

 

[baker332]

If there is an importance that the two are to be fully bonded, then it could mean a rebuild in any case.
What did the engineer suggest?

It's not written into the detail just in a conversation best to bond using common bond new skin to old skin.

 

[baker332]

Post a plan or something, I can't make head or tails of it.

Apologies Woody.

I'm effectively doing the same as this: (cbde picture)

Knocking through, steel on stop of padstone, this is where the cavity was once, there is a gap, I need to brick it up. Suggested to tie the new to old brick work but one cavity is 75mm the other is 100mm.

For strength is it better to step the brick work and have 25mm gaps all over or angle the brick ever to slightly? (Tony picture)

The new brick work on the right being 100mm and on the original left being 75mm cavity.

Distributed load on the top of this brick work from the steel is 26.58Kn

 

[^woody^]

Take the new blockwork past the padstone, and block-bond it in so that the padstone and beam is bearing on the new blockwork and then the load from the beam is properly transferred down along the whole wall not just vertically down the bit below the beam

 

[baker332]

Take the new blockwork past the padstone, and block-bond it in so that the padstone and beam is bearing on the new blockwork and then the load from the beam is properly transferred down along the whole wall not just vertically down the bit below the beam

You are saying step in then from the 75mm to 100mm but bond with the new wall only?

I started a couple of blocks and realised I'm angling the block to suit not stepping in and wondered if it's allowed in the regs, hence asking the question.

You can't really tell from the picture but it's at a slight angle - the best option is to remove this, and step in?

 

[^woody^]