What’s the right mortar mix for repointing a 1970s brick house?

[lin27]

     

Hi everyone, I’m planning to do some repointing work on my brick wall. The house was built in the 1970s, and the original mortar clearly shows fine sand in the mix. However, the premixed mortar I see being sold nowadays looks much smoother and doesn’t seem to contain visible sand.

Does anyone know what would be the right mortar mix to match the original 1970s style? Should I be adding sand myself, and if so, what type/ratio would be best? Any advice would be much appreciated. Thanks.

[MitchellMc]

Hi @lin27,

On the scale of sand used in mortar mixes, even for a 1970s build, the aggregate would be considered quite coarse. It’s unlikely you’ll find sand that coarse straight off the shelf these days. If you wanted to make your own mix, a common ratio is about 1 part cement, 1 part hydrated lime, and 6 parts washed sand. Adjusting the sand type can help you replicate the look of your original joints more closely, but the readily available washed brickie’s sand is usually what’s used today.

That said, modern pre-mixed mortar is perfectly fine to use, though it won’t be an exact match to what you currently have. Apart from the sand particle size, the more important factor will be getting the colour right. A slight difference in sand texture will likely go unnoticed to most people, but a colour mismatch stands out straight away. If the premix you choose looks too light or too grey compared to your existing mortar, you can use oxide additives to tint it and achieve a closer match. 

Here's a helpful guide: How to mix mortar.

Please let me know if you have any questions.

Mitchell

[lin27]

Hi Mitchell

May I ask what tool you recommend to remove the mortar between the bricks? I did some research, but some people say grinder with mortar blade, some say oscillating tool, or Morta Sortas Diamond Coated Mortar Rake. I cannot find proper tool in Bunnings shop.Thanks.😬

[MitchellMc]

An angle grinder with a diamond blade would likely be the fastest option, @lin27⁠⁠⁠⁠⁠⁠⁠. An oscillating tool is fine for small sections, but it doesn't work well on larger areas because it's quite slow. However, if you are not confident and have experience using an anglegrinder, it might be better to take your time and use the oscillating tool.

Mitchell

[lin27]

which oscillating tool and bit you recommend from Bunnings shop?

[MitchellMc]

The XU1 220W Multi Function Tool would be a good candidate as it is budget-friendly and 240V powered, @lin27. It will have more grunt than the battery-powered versions. You'll also need a carbide cutting bit for it.

Mitchell