Mortar lime

parking_question_chap

Morning

Need to do a small repointing job on an external cavity wall. Just around 20cm by 20cm around an old boiler flue. Do I need lime in the mix? or would a Blue Hawk Sand and Cement Mortar Mix Bucket like sold at homebase be ok?

Thanks

Furts

There is a lot more to mortar than meets the eye, but in general your area is so small it is unlikely to matter much.

Typically a 1:1:6 mix would be fine, this being OP cement, lime and building sand. The critical item is colour matching, so find out if you need yellow or red sand.

The premixed will probably be fine. I will leave it to you to check the mix strength (1:3 is too strong) and colour.

TomSawyers231

If the mortar was cement, stick with cement. If lime mortar has been used, only used lime mortar, and what ever you do not mixed it with Cement. With cement being added to the mix it will take all the unique benefits of lime mortar away. regarding colour buy ready mixed (pre-mixed) hydraulic lime mortar, quick easy and all you need to do is add water. Also, you can used it for pointing else where as long as you keep it dry. these guys are great for limetec.co.uk

FreeBear

I've been doing some patching with lime mortar. Don't have to worry about colour matching as the stuff will be hidden by a coat of plaster when I'm done. The mix I'm using is 2.5 measures of sifted dry sharp sand to one measure of lime putty. if you don't want to mix your own, then you can get ready mixed tubs. Limetec has already been mentions, so I'll throw in Anglia Lime and Mike Wye.

As long as it is kept wet and in an airtight container, the mix remains usable for months.

One tip - Spray the area well with lots of water. You want the surface to be damp, but not dripping wet.