Thin-bed mortar/adhesive options for linear facing bricks (not blockwork)

[ed g]

I've just had a trip via Belgium on the way to the Netherlands with the kids, and was really taken with the thin-bed 'mortarless' look you can get with the linear facing bricks - see photo - (the adhesive mortar is 3-6mm rather than 10-12mm thick and when set back a little from the brick face it means you only see the bricks, not the mortar). When speaking to a Belgian Wienerberger chap, he said that 5mm may be acheiveable but 6mm was probably realistic given the brick tolerances to give a bit a lee-way.

 

I know the brick is a Wienerberger Special Waterstruck, which I can get hold of in the UK through Huws Gray, but don't know what adhesive mortar options there are. Googling brick adhesives only seems to bring up brick slip/tile adhesives...

- Are facing brick adhesives separate and different from thin-joint mortars, e.g. https://www.vandersanden.com/en-uk/adhesive-and-thin-bed-mortar and https://www.nelissen.be/en/products/mortars/adhesivemortar? Other forums seem to talk about them differently and with slightly different thicknesses: "adhesives" give 3-6mm thickness, "thin-joint" may be 5-8mm

- I've found Celfix is one option for thin-joint blcokwork - would this work for waterstruck facing bricks where the tolerances are a lot bigger?

- What other brands/ products are there that work for this use? UK-sourced options seem limited and it seems daft importing the mortar from Europe...

 

Any help or insight much appreciated.

Cheers   

[Oz07]

Digression but have you seen how narrow some of the joints are on some victorian stuff. Very much like 6mm on some houses makes you appreciate how good they were at setting out and cutting. 

[ed g]

On 02/09/2024 at 09:54, Oz07 said:

Digression but have you seen how narrow some of the joints are on some victorian stuff. Very much like 6mm on some houses makes you appreciate how good they were at setting out and cutting. 

You make an interesting point - so can thin joints (say 5-6mm) be reasonably achieved with a normal mortar - it's just down to the bricklayer's expertise? Does it require changes to the mix? Given the bricks I plan on using are 45mm high, there'll be fun-and-games to get wall ties right in any event, but is there anything else to think about? I think one of the problems as the joints get thinner is that the moisture levels in the mortar can get risky? Presumably this depends on the brick? Can this be adjusted for in the mortar mix chosen?

Edited September 4 by ed g

[Mike]

10 hours ago, ed g said:

so can thin joints (say 5-6mm) be reasonably achieved with a normal mortar - it's just down to the bricklayer's expertise?

The first problem thin joints is that they need a fine sand, rather than regular bricklaying sand. However a fine sand will weaken the mortar, and also take you outside the scope of the British Standards. Traditionally a mix of lime putty & (I think) silver sand would have been used, which would be a better bet than using cement, since it will absorb movement and self-heal, rather than crack.

 

The second problem is a regular mortar bed can cope with deviations in brick size. As the joints become thinner, the bricks need to be more accurate as any deviations will be more apparent. Alternatively, you need to use traditional rubber bricks - which aren't made from rubber, but soft bricks that need to be individually rubbed / ground down to meet the tight tolerances required.

 

I can't see why moisture levels would be a problem.

 

On 02/09/2024 at 10:14, ed g said:

I know the brick is a Wienerberger Special Waterstruck, which I can get hold of in the UK through Huws Gray, but don't know what adhesive mortar options there are

Your best bet would be to ask Wienerberger. I'd guess that they either have a recommended mortar specification, or will sell a special one themselves, and that they will specify a suitable mortar joint thickness that suits the tolerance of their bricks. Through doing it the old way with lime putty would be an option, subject to convincing Building Control.

[Brickie]

On 02/09/2024 at 09:54, Oz07 said:

Digression but have you seen how narrow some of the joints are on some victorian stuff. Very much like 6mm on some houses makes you appreciate how good they were at setting out and cutting. 

Possibly you’re thinking of Tuck Pointed brickwork-a fairly common practice at one time to give the illusion of very accurate,thin jointed work.