How to age stone faster than nature ?

[broadclose]

My house is built of coursed stone which has obviously aged over the years and is quite dark, almost black in places. A couple of years ago I had an extension built which is also stone coursed in to line with the original stone. The extension is not new stone but it is a lot lighter than the original house. The builder said that it would weather and darken in a couple of years but I think he must have meant a couple of hundred years because there is no noticable change in colour since it was built.

Sandblasting the original stone to lighten the colour to match the extension has been suggested but I don't want the expense or possible repointing needed after sandblasting.

Does anyone know any tried and tested permanent ways to age/weather/darken stone quickly ?

Any ideas appreciated.

 

[JohnD]

mix live yoghurt with water, and paint or spray it on


(this is not a joke)

However If you live in an area that used to have coal fires, then modern clean air will not deposit soot on it (and a good thing too).

 

[AndersonC]

I was once told a tale of a guy who converted a barn and re-built all the external stone walls, during which he got the stones cleaned so they shone out. Unfortunately for him, there was a similar building nearby which didn't have the stone cleaned and was covered in lichen etc (they were about 200 years old).

The building control lot went down and told him he needed to get his new external walls 'aged' to look like the other building and apparently they ended up spraying the outside of the place with diluted cow sh*t to accelerate the growth of natural lichens etc!!

 

[Deluks]

Apparently you can use soot on brickwork to age it. That's soot mixed with water and brushed on. Don't know how if would work on stone, is it porous?

 

[JohnD]

apparently they ended up spraying the outside of the place with diluted cow sh*t to accelerate the growth of natural lichens etc!!

the yoghurt does that too, but is more pleasant.

 

[AndersonC]

I can well imagine

 

[broadclose]

Once again, speedy responses to my questions, many thanks. There would have been coal fires where I live and so maybe this explains a lot of the darkness on the stone. I will try a couple of experiments on a small area at the back of the extension. Yoghurt/water and maybe even yoghurt/water/soot. There's no cow sh*t where I live, plenty of horse sh*t but I'll give that experiment a miss.

I'm still open to any other experiments or suggestions.

Thanks again.

 

[^woody^]

A 'soot wash' is what is done on conservation work to blend in new to old work.

Soak coal or soot in water overnight, and then brush on. The grains of soot will lodge in the pores of the stone or brick. May requie a few goes

Yogurt or milk promotes mildew, which is not always a natural occurance, and you may end up scrubbing it all off again

 

[Bowness72]

As already mentioned I think soot might be the way to go. I have worked on a new stone building before where the planners requested that it be sprayed with soot to blend in with the adjacent buildings, although it didn't happen in the end but that suggests it is a recognised way of achieving what you want.

 

[broadclose]

I don't want mildew I just want to darken the stone so soot looks like the thing to try. I guess I'll have to get the chimney sweep round and ask him to collect all the soot he can from my chimney or I can get a bag of coal. Does anyone know if the lumps of coal need crunching into smaller pieces or to coal dust before soaking in water ?

 

[EdF]

Just a thought, but why not lighten the dark bits?? Power wash or bleach...? Might look newer. If you spray it with yogurt, will you get vegetarians licking your house?