Lime Mortar Too White?

[BlueRam]

Two years ago, I brought a 200 year old Cottage in the Cotswolds. The cottage was built with cotswold stone and over the years, the pointing was patched up using cement The good news is that I decided to repoint the entire house using lime mortar. The thing I am finding is that the mortar seems to be very white once it has gone off. When I use it, it looks the perfect colour and matched the stonework pefectly. However, after a month or two, the colour turns more to a whitish colour. My question is, is that how all new mortar is and is this just the lime coming through? Am I not keeping the mortar wet enough after repointing? I assume it will age over time but I was just worried that the 3-1 mix I am buying has not aged (would this cause it to become more white?).

I have even emailed Jane Schofield after buying her book (which is a must for novices like me!) and she does not think this is a problem (please see her reply below) and I just want to check that I am worrying about nothing!

If you brush your joints at exactly the right time, then you should be able to "expose" the stones in the aggregate which will lessen the glaring whiteness! However, it will be quite light at first, but should weather back quite a bit in time.

Glad to hear you've got the bug as well!

Jane

 

[NT]

Lime is used as white paint, so I'm not really surprised. The strength of whiteness does much increase over a few days.

If you want a broken white, you could add a very little subsoil into the mix. Bit late now though. Or red sand will give you a pinker mortar.


NT

 

[Anonymous]

Hi BlueRam,


You'll be happy to learn that it's not just you this happens to!

Ideally you should try to keep the pointing damp ie. give it a light spray of water every so often, and protect it with tarp coverings -- to allow the pointing to set slower. However, in the real world, sometimes its just not feasible to do this -- in my case work at height with bad exposure to the unpredictable weather.

One thing I found (through experimenting from advice given by helpful posters on this forum) is that rubbing in dust/sand when the pointing is "green" hard (just setting) helps to colour the mix to match the stonework. Be warned though, if you rub in topsoil too early the pointing can go a grey shade - exactly like the colour of cement!

Hope this helps.

Peter

 

[BlueRam]

Many thanks for the replies. I think I will go with the keeping it wet option as I know I will mess up if I try anything different :?

When I did the first wall, I was doing it inbetween working so I would do a bit of the wall and then be away all day at work so was not able to keep the wall wet. This time, I have taken a few months off work and all I am now doing is the wall so I can keep wetting the wall 8-10 times a day.

I have noticed that the first wall I did was south facing so keeping it wet was impossible. Just as quick as you wet the wall, it dried. I am now doing a east/north wall and have noticed the mortar is not so white. Must be something to do with it not drying out so quick.

One last question, I assume it will age. Anyone have any experience on how long it can take for the whiteness to fade?

 

[middi]

If you use a thin wire brush as the lime/sharp sand pointing is reasonably hard set ( one or more days later) you will remove the "glazing" effect of the trowel, the small stones and sand will be slightly exposed and the immediate " bright" look should disappear. Within a year or so the exposed particles will be further washed and rinsed by rain, frosts and so on and it will start taking on a more natural appearance.

 

[Sue Wilkinson]

South facing is a problem. But if you do as Jane suggests and brush the pointing at the point that its almost hard, (I bash it with a bristle churn brush, I like the effect better) you remove the latent lime that's been pulled to the surface as you worked it with a metal tool, and the aggregate does show up and make it all look much better.

But yours sounds like its been done a while, so just give it some time. After 2 years my south facing wall is starting to look less bright.

Sue

 

[BlueRam]

One last question (honest ). I have a few cracks in the mortar as it dries. Is this is also to do with allowing it the mortar to dry too quickly?

 

[RobT]

BlueRam,

try brushing on a small amount of diluted tea on to the pointing.

Dilute with water to gain required colour.

regards

Rob