Cleaning stonework

[JohnArmer]

This spring's project is having the front of our house repointed in lime, but wondered if anyone can suggest whether / how I should have the stonework cleaned once I've raked out the old ribbon pointing.

I know you like pictures so here's one I took when we had the old Bay window replaced (there's now a nice sash above the bay window and the door is next after the pointing's been done).

 

[malcolm]

My preference is not to clean the stonework. I didn't have my bricks cleaned as I think they would have looked too new and I think the sooty bricks look OK with new pointing and they brightened up a bit when the new pointing was brushed - photo on http://www.periodproperty.co.uk/forum/viewtopic.php?f=1&t=15196

If you do have the stones cleaned then just about any way of cleaning them will damage the pointing so would be better done before the pointing has been raked out. The people who offered to clean mine wanted to use brick acid.

 

[JohnArmer]

Thanks for your reply Malcolm. If we do have the stone cleaned, it would have to be after the ribbon pointing has been removed because it covers up about an inch of the stone. If we didn't there's be an inch of different coloured stonework!

 

[malcolm]

Cement re-pointing is normally done without any raking out of the lime at all (unless you are unlucky and someone tried to do it properly) which makes it much easier to chip off and put right. Water trapped in the lime mortar by the cement seems to make it soft and maybe an inch depth will come out just by scraping with a screwdriver before you get back to firm mortar. It is worth chipping the cement off but not raking out any soft lime until after the stones are cleaned if there is a chance of damaging good lime mortar with the cleaning process.

It doesn't look like you would need much cleaning. Have you tried a scrubbing brush with hot soapy water in a corner somewhere? This far from any area of expertise I might pretend to have.

 

[Roger H]

It's patina and looks fine as it is. The sash in the bay window is super too.

 

[DJH]

By coincidence there is an article 'Home Improvement' in the latest edition of The Georgian issued (should I say uploaded Lady A 8) ) by The Georgian Group with a section among others about brickwork which I suppose could apply to stone as well, and they say....

as for cleaning don't if you can avoid it. Soot in particular is an adornment, part of the building's patina...

Doug

PS In the same article there is this.....

If brick is covered by render ...it may be to protect the brick or conceal unsightly or deteriorating bricks

In 1796 Lord Bristol whose daughter wanted to use white brick to build Ickworth wrote to her...

What! Build my house of a brick that looks like a sick, pale, jaundiced red brick...No my dear I shall follow dear Palladio's rule and as nothing ought to be without a covering in our raw damp climate, I shall cover the house in Palladio's stucco...

Doug

 

[Lewis Tiffany]

If the lime point doesn't follow the same area as the ribbon pointing it will show a difference in colour .
Knocking the ribbon pointing off will pull off some stone and leave a clean line around the edge of the stone .

You will also find some of the cement will not come off and the only way to remove it is by scutch chisel or blasting .

The colour differences between new and old will weather in time but will probably be noticeable for quite a while.
I would knock the ribbon point off .
rake out the all the cement from the joints and then start again as from new and have it all sandblasted.

Wet blasting will make more mess for you and less for your neighbour.

With dry blasting put some duck tape over your key hole and letter box and block and all airvents tape up windows inside tell your neighbours and pay to have their windows cleaned and move all cars away from the area.
Be prepared for a house with full of dust.

Also wait for warmer weather especially if using lime

 

[Roger H]

have it all sandblasted

I wouldn't think sandblasting would be a good idea unless you want to accelerate the decay of your stone work, or the stone is some tough as nails granite or gritstone.
http://www.buildingconservation.com/articles/stone98/stone98.htm

 

[MatthewC]

I think I would just re-point and give it a decent going over with a stiff churn brush before and during doing the pointing; then let time take its course - once the wall is able to dry out properly, I expect a lot of the colour would come back naturally.

A local war memorial here was cleaned by DOFF (high pressure water) last year and frankly it looks so new, it's terrible! I can't wait for it to weather a bit.

 

[JohnArmer]

Update: after much consideration, decided not to clean the stonework... but did jet wash it with cold water. It got a lot of dirt off, particularly on the lintel above the door which was filthy.

It was the right decision I think, not too clean and the lime makes it look lighter too. I know, the bin has to go!

 

[mims&pip]

Gosh, that looks so much better

Mims x

 

[plasticpigeon]

Brilliant, and the new door and window set the revived facade of a treat! Taking a photo on a sunny day also helps!!!

 

[steveb]

Excellent result - if there was ever an advert of why not to clean stonework, this is it.

 

[88v8]

Crumbs. What a difference. The various stone types, visible. The ugly slab of glass, gone.
Restraint, sensitivity, jolly good.

Now you can treat yourself to a more 'important' flower pot.

Ivor

 

[angrybird]

Wow! That looks amazing

 

[Roger H]

That looks great. Love the new door and window upstairs. Lovely pointing too. I hope the neighbours take note.