Colouring mortar off-white

In message , JD writes

You can buy white cement from builders merchants. Also use washed sand. Real lime mortar has small embedded chunks which may be hard to reproduce.

I've used 60/40 white cement/lime and sharp sand.

looks very olde fashioneded.

On Tuesday 31 December 2013 11:06 wrote in uk.d-i-y:

And if you are going for a light colour, you may want to use SnowCrete instead of cement (it's white cement) and watch the sand - silver sand aka PlaySand will give you an almost white base colour to start with.

I used Snowcrete and silver sand plus a little lime when rendering a fireplace opening that I wanted to whitewash (with real lime). It produced a very light (but not brilliant white) render.

You may find that snowcrete and certain building sands may actually give you the colour you want without dyes.

If you do dye, the colour will fade a lot as the cement dries. ie you will need to mix darker than you think.

Most 'garden lime' isn't lime (i.e. calcium oxide) these days, it's simply ground limestone (I guess H&S considerations for proper lime in garden centres excludes it!). Ground limestone might be perfectly OK to add to cement to alter the colour, but it won't have the setting properties of true lime needed for lime mortar.

You can probably get proper lime if you look around, but avoid 'garden lime'.

I assumed the OP was tinting a cement mortar

Garden lime is a mixture of slaked lime (calcium hydroxide) and ground limestone. (Calcium carbonate) The first has a quick effect the second weaker but more long lasting.

Builders sell lime (calcium hydroxide) in 25Kg bags. I use it in the garden as it's much cheaper than garden lime.

stuart noble wrote in news:gmzwu.613$E92.533 @fx08.am4:

That was the idea, yes.

Thanks to all for the suggestions. I like the sound of the white cement, and silver sand. Though now I think about it, I'm wondering if it might make sense to use *real* lime mortar! At least the fireplace will then be easier to dismantle, if, say a buyer of the house disapproves of it, or if I decide to modify it.

I've never used lime morter before. Would it be a sensible option?

TIA

JD

its a bit of a pig. I definitely recommend a mix of lime and white cement and indeed yellow sharp sand, if you want a vintage look that sets relatively quickly, is a bit crack proof and generally works.

viz the fireplace here

The Natural Philosopher wrote in news:l9v6lj$gnc$1 @news.albasani.net:

I'd like to end up with a mortar colour somewhat whiter than the mortar in the above photo, to achieve a look more akin to the kind of very light- coloured lime motar I've seen in the old buildings in my vicinity. So perhaps using the silver sand per stuart's suggestion might achieve this. I like the sound of mixing builder's lime with the white cement, can you suggest a ratio of lime:cement:sand? I'd like to end up with a mortar that dosn't crack easily, say due to heat expansion, but doesn't pulverise when, say, brushed with a stiff brush, after it has fully cured.

Regards (and Happy New Year to all the helpful folks uk.d-i-y)! JD

silver sand will get you there or just less sand..

It also effloresces like a SOB for a while.

you dint need to worry about cracking on stone/brickwork in fireplaces. The back of my fire has eroded due to heat before I got a steel fire-back in, but never cracked.

The Natural Philosopher wrote in news:l9v8lj$khm$1 @news.albasani.net:

That sounds ideal - thanks! I'm not too concerned about efflorescence, as I'm building it with off-white limestone.

JD

Tim Watts wrote in news:pnnapa-om8.ln1 @squidward.local.dionic.net:

Thanks for the great suggestions. Where does one obtain silver/play sand and snowcrete? I can't remember ever seeing either for sale... but then, I wasn't looking out for it!

JD

In message , JD writes

you can get silver sand/play sand in most diy sheds etc. - for use in kids sand pits. Though probably not the cheapest way to buy it

I've seen it offered for sale by bulk suppliers as well.

If you stir ordinary building (i.e.soft) sand in a bucket of water, the pale stuff drops like a stone and the orange coloured (ochre?) stays water borne for longer, so "washing" is easy

If you use lime & yellow sand, you get a near white. The lime's white very much dominates. If you need more offness, yes emulsion works fine, yellow in this case.

Using cement & dye to try to match lime seems a weird approach, its not going to work as well as using the real materials.

If you used silver sand, you'd get pure white.

NT