Darken lime mortar?

[Greenbeast]

I've got to brick up a couple of windows and have plenty of lime to make the mortar with but i expect it will come out quite white (my limecrete did), is there any way to darken it to match in with the existing brickwork mortar

[guydewdney]

add red sand.

[Greenbeast]

thanks, i'll give that a go

[noelsquibb]

If you want a good match you might want to do a few trial mixes.

As Guy says, darker sand will help but if your original mortar mix used a yellow sand, I doubt a red sand mix will do it.

Theres colour tone admixes and theres lighter or darker cements, which can be a right nuisance if you buy on price and find its different.

Try a 1:1:6 mix ( cement, lime, sand) and try different sand colours or a colour tone powder and keep a note of what you did.

You could leave it for a week or so to allow the moisture content to stabilise if you want a perfect match.

But the Heritage dreamers prefer you use something different, so future historians can 'read the building' ........

[Greenbeast]

i was trying to get away from cement, as i bought the lime for eco reason over it in the first place and only need to do a little.

My limecrete didn't use any cement
Do i need it in my mortar?

[guydewdney]

you dont NEED cement - it does make it stronger though.

Cement is pretty brittle, lime is soft. The totalo construction of the wall has to have some flex in it - in a brick building, its very very stiff, but the bricks move slightly. Round here, we use beach pebbles, which are incredibly hard (you cannot drill them) so we use a lime mortar mix, often with a bit of cement, so the mortar flexes slightly as the pebbles cant. The same would apply for flint walls I suspect.

[AlanM]

You can avoid cement. If you want a quicker chemical set or a stronger set,  you could use a hydraulic lime or add a pozolanic material such as brick dust, to your mortar

The brick dust may give you a darker colour too perhaps

[tony.]

add some soot to darken the colour, im sure the SPAB leaflet advocates this, but its been a couple of years since i read it
tony

[Tombo]

I'd steer clear of colour admixes. They are fine indoors but they fade when exposed to the sun. They are expensive too.

[Greenbeast]

You can avoid cement. If you want a quicker chemical set or a stronger set,  you could use a hydraulic lime or add a pozolanic material such as brick dust, to your mortar

The brick dust may give you a darker colour too perhaps

i've got NHL5 already left over from limecreting

add some soot to darken the colour, im sure the SPAB leaflet advocates this, but its been a couple of years since i read it
tony

someone else has suggested soot too, any good ideas on getting hold of it?

[guydewdney]

follow a chimney sweep around?

[biff]

ahhhhh my trade,
      soot is the answer,mix it into a bucket of water and brush it on, the suggestions  you are getting here are mostly right, the mix you are aiming for is 1 of lime,5 of sand, and a half of cement, you will not need plastersiser because the lime is present,the sand should not be too rough(like floor screeding sand) but rather fine like the red sand you get in kent,B n Q do this in bags,make sure the bricks are dry and clean,do not use wet bricks this time of year.do not make the mix too strong and if you feel that the colour is not right,rake out the joints back 25mm when the mortar has gone dry but not set,then you can point it with a mix which you feel is closer.
                    biff

[daftlad]

The red sand we have round here turns the mortar pink, it looks terrible.
ta ta

[Greenbeast]

thanks biff

[biff]

dont worry the lime will lighten it,if in doubt,seek out a builders yard with a mortar mill and have a bin of mortar delivered, you can add cement to speed up setting. the only drawback in ordering the bin is, you have to be well organised and do the job in 3 days or the bin will begin to go off so mixing your own will allow you to work at your own pace.keep the bin sealed with a plastic cover,when not in use.
                               biff