Bleeding Stone!

[Johnboy]

About 6 months ago we had the sand-blasting man in to our Welsh cottage to remove the snow-cem(?) that covered the dining room walls and also to clean off the 'lovely' brown paint from the roof beams and fireplace lintel. I have recently noticed that some of the stones appear to be bleeding and sadly, it's making a fair mess of the new lime pointing. It seems to be confined to the darker stone and it's not all of them? The same is happening to the some of the stone inside the sitting-room fireplace, again not all of them. Here's a picture of the wall WIP. Like I said, the bleeding seems to be confined to the darker stones. There are a few very small ones in the first picture and a couple of larger ones in pic 2. I am waiting on some more recent pictures and will post them as soon as they arrive.

This picture shows a couple of the darker stones, they are the one's 'leaking'

Any ideas?

 

[JoceAndChris]

Do you plan to put some lime plaster back?

 

[Penners]

the bleeding seems to be confined to the darker stones

Poor house - I reckon I'd bleed if someone attacked me with a vicious sandblaster. They're monstrous things.

Are you sure that your explanation isn't identifying the problem from the wrong end? In other words, could it be the moisture that's making certain stones dark?

Have you checked to make sure that the external pointing is sound? I'm wondering whether certain of the stones are poorly pointed and are allowing damp to seep in/around them.

Where is the outside soil level?

In your picture I can only see one dark stone outside the fireplace. Is the problem principally within the fireplace? If so, then it's possible that soot staining is somehow involved. The back wall of the fireplace is also in dire need of repointing.

Can you be a bit more specific about the "bleeding"? What is it? Is water oozing out of the stone and standing on/running down the surface? Or is it some other form of liquid?

A close-up picture of one problem stone might help.

 

[Johnboy]

Poor house - I reckon I'd bleed if someone attacked me with a vicious sandblaster. They're monstrous things.

Are you sure that your explanation isn't identifying the problem from the wrong end? In other words, could it be the moisture that's making certain stones dark?

Have you checked to make sure that the external pointing is sound? I'm wondering whether certain of the stones are poorly pointed and are allowing damp to seep in/around them.

Where is the outside soil level?

In your picture I can only see one dark stone outside the fireplace. Is the problem principally within the fireplace? If so, then it's possible that soot staining is somehow involved. The back wall of the fireplace is also in dire need of repointing.

Can you be a bit more specific about the "bleeding"? What is it? Is water oozing out of the stone and standing on/running down the surface? Or is it some other form of liquid?

A close-up picture of one problem stone might help.

The 2 pictures are work in progress and don't really show the offending stones that well. Since taking them 99% of the pointing has been finished in lime including setting all the wiring into the wall. The fireplace will remain un-rendered for a while as we can't decide whether to go the wood-burner route or have the chimney lined for a real fire. It was used with a real fire before we owned it but apparently wouldn't draw very well?
On reflection I would be wary about using a sand-blaster in the future but it couldn't be avoided on this occassion as the original finish was definitely there to stay! I tried just about every available option but it just wouldn't budge and there's only so much fun can be had scraping paint off with a pen-knife...
Outside, the soil level is well below the base line of the cottage and of the 4 walls in question 3 are internal and the 4th an external rendered wall. The problem stones are randomly placed and seem to be a different type to the majority, they are a dark, 'rusty' colour and the stuff leaking looks almost like sap??

Oh, and just in case anyone wondered, the cottage isn't in Amityville!

 

[Penners]

Well, funnily enough, newly quarried stone is described as still having its "quarry sap". Stonemasons find it much easier to work such stone before the quarry sap has dried out, causing case-hardening. But it is, in fact, nothing more than groundwater that hasn't dried out of the stone.

I find it very hard to believe that any of your stone still contains its quarry sap, or that - if it did - it would look like sap!

What happens if you try to wash the sap off? Is it water soluble, or do you have to use a solvent like white spirit?

As I said before, a close-up photo might help.

 

[Johnboy]

Our next visit to the cottage won't be until mid July but I will take some pictures then. From memory the 'sap' washes off with detergent water but does make a mess of the lime pointing.

 

[worms]

I remember posting some time in the distant past that my rubble stone walls have the odd stone that always seems to be damp. I can only assume it is something to do with porosity and how they react to fluctuations in humidity or rain. Once whitewashed, they still react slightly differently, with a tendency to support moss growth, but I reckon the effect is reduced with increasing layers of limewash.

In your case, I would imagine that making sure no new moisture is getting in from the outside and a year or two to let them completely dry out might help, by which time everything will look less new and the damp ones will be less noticeable.

 

[geoff]

Your stone looks remarkably similar to mine in colour and texture (mid wales). I find occasional stones can have naturally occurring oxides/minerals which sometimes bleed out. In my case it seems to be iron compounds which have the typical dark brown rusty colour; on the outside of the building there are brown points and streaks in a few places which stain right through the masonry paint. I haven't found any way of stopping it - I suspect they may be hygroscopic compounds (which attract moisture from the atmosphere) so you either seal them (not always possible or desirable) or just put up with cleaning the stones affected.

 

[Moo]

either seal them (not always possible or desirable) or just put up with cleaning the stones affected.

Or (my preferred option, but I'm congenitally lazy) learn to love it as it is.

 

[Johnboy]

Your stone looks remarkably similar to mine in colour and texture (mid wales). I find occasional stones can have naturally occurring oxides/minerals which sometimes bleed out. In my case it seems to be iron compounds which have the typical dark brown rusty colour; on the outside of the building there are brown points and streaks in a few places which stain right through the masonry paint. I haven't found any way of stopping it - I suspect they may be hygroscopic compounds (which attract moisture from the atmosphere) so you either seal them (not always possible or desirable) or just put up with cleaning the stones affected.

I think you have hit the nail on the head geoff, it certainly looks more like rusty moisture this time.

It will clean off but I am getting more and more used to it!

 

[MdB]

Well when you said bleeding, you meant it. :shock:

I think I would go as far as saying that there is something within that rock to cause that. Tar pocket maybe? I would guess that there was little you could do apart from either replacing the stone or possibly varnishing it which probably would look equally as bad.

 

[piapiapiano]

Your stone looks remarkably similar to mine in colour and texture (mid wales). I find occasional stones can have naturally occurring oxides/minerals which sometimes bleed out. In my case it seems to be iron compounds which have the typical dark brown rusty colour; on the outside of the building there are brown points and streaks in a few places which stain right through the masonry paint. I haven't found any way of stopping it - I suspect they may be hygroscopic compounds (which attract moisture from the atmosphere) so you either seal them (not always possible or desirable) or just put up with cleaning the stones affected.

I was going to say something like this. We've had the same thing with random stones in our rubble walls after re-pointing and it does look like iron oxide leaching out. Personally I rather like the effect.

Oh, and the re-pointing you've done looks lovely!

 

[88v8]

....... would be wary about using a sand-blaster in the future but it couldn't be avoided on this occasion as the original finish was definitely there to stay!

Plastic blasting is kinder, and will not destroy the texture of the underlying material.
These guys do a lot of it and will travel all over the UK. They even Hoover up the plastic afterwards.
http://www.blast-cleaning.co.uk/building.html

Ivor

 

[Flyfisher]

I've only heard of plastic (and soda) blasting being used for vehicles, and the above website also mentions it in conjunction with cars.

Also from that website:

Fine grit blast cleaning is used for old oak beam cleaning to remove paint, dirt, grime and smoke soiling and restore the natural warmth of the wood.

. . . so it would be advisable to verify their precise technique for blasting beams, as well as insisting on seeing a sample of cleaned wood before committing to any irreversible procedure.