Grass

[Jacob]

Moss holds onto water like a sponge, when water freezes it expands by 9% so any small imperfection in the roofing material will be exposed to this hydraulic action.

Yes but have you seen evidence for this i.e. old moss removal revealing higher than expected broken slates/tiles etc. ?

this is how the Egyptians quarried rock for the pyramids.

Really? And have you any evidence for this?

I have no affiliation to any moss removal company

Yes but have you seen their adverts?

It just seems very unlikely to me - if anything moss would protect the surface from temperature extremes.
Happy to be corrected on this!

 

[Misterdog]

Really? And have you any evidence for this?

Definition: Freeze-thaw weathering is a process of erosion that happens in cold areas where ice forms. A crack in a rock can fill with water which then freezes as the temperature drops. As the ice expands, it pushes the crack apart, making it larger. When the temperature rises again, the ice melts, and the water fills the newer parts of the crack. The water freezes again as the temperature falls, and the expansion of the ice causes further expansion to the crack. This process continues until the rock breaks.

https://www.ssc.education.ed.ac.uk/...t=A crack in a rock,newer parts of the crack.
https://www.geolsoc.org.uk/ks3/gsl/...hen water,pressure during uplift and erosion.
https://www.google.com/search?sxsrf...AHbnBCx8Q1QJ6BAglEAE&biw=1051&bih=508&dpr=1.3
Nature has existed for far longer than JCB's and Kango's.

 

[Jacob]

Definition: Freeze-thaw weathering is a process of erosion that happens in cold areas where ice forms. A crack in a rock can fill with water which then freezes as the temperature drops. As the ice expands, it pushes the crack apart, making it larger. When the temperature rises again, the ice melts, and the water fills the newer parts of the crack. The water freezes again as the temperature falls, and the expansion of the ice causes further expansion to the crack. This process continues until the rock breaks.

https://www.ssc.education.ed.ac.uk/...t=A crack in a rock,newer parts of the crack.

Yes. Have you seen any particular evidence of this with roofs, caused by moss?
Or even first hand accounts?
I presume not.
No wonder pyramids took so long to build if they were hanging around waiting for frosts all the time!

 

[mwinfrance]

Yes but have you seen evidence for this i.e. old moss removal revealing higher than expected broken slates/tiles etc. ?

Yes..We live in an area with 99% of the houses having slate roofs ( Brittany ). In Ireland a large part of my home area had / has slate roofs.I know Wales very well, most of the houses in North Wales have / had slate roofs.
When you re-roof with slate , you remove the old ones ( I have done this many times ) where there was moss on the old ones , when you remove the moss, the slates show pitting , splits , and "flaking" damage.Unless your slate roof has been damaged by hailstorms or other percussive events, the absolute top reason for repairing it or replacing it is due to damage and or breaking of or displacement of slates due to moss damage.

Jacob..put down the spade and quit digging, you are making yourself look stupid in the face of the wide experience" of others here in the matter, I only posted this so as to avoid anyone falling for your usual stubbornness ( on this subject ) in the face of facts ( which does you no favours ) , anyone with a slate or tile roof following your thinking on the subject of moss on roofs would have to deal with the effects of moss damage long after you were gone.

Yes it looks picturesque ( I am a professional artist / sculptor , have been for 50 years ) but the charm ceases when a slate or a tile comes off or is broken due to moss damage and your roof leaks.My immediate neighbours had to replace their slate roof 5 years ago, the cost was horrific, nearly 25% of what they paid for the house.
We are in an area of slate quarries ( all now closed ), I also know the slate quarries at Blaenau Ffestiniog very well ( I think most , if not all of of them are now closed for roofing slate supplies, I used to buy slate discs by the tens of thousands from them for screen printing my designs on back in the 70s and 80s, I've talked at length with slate quarriers in both Wales and Brittany. Now some slate comes from Portugal, most is imported from India* ( as is the case with a huge amount of "decorative stone" ) when you go the now non working quarries , you can see the damage done by moss to the rock in situ, and if you have replaced slates or an entire slate roof because of damage due to moss being left to attack them, you would not be stubbornly talking such bolleaux.

When moss is growing and when it breaks down, it produces acids upon contact with water, said acids attack ( slowly ) whatever it is growing on**.

How do I know this ? A degree ( along with my arty ones ) in organic chemistry and experience, and experimentation.

* Not very "green" shipping slate halfway around the world to replace those slates and rooves damaged by allowing moss to grow on slate rooves.
added..you know Jacob , politically you and I are not so far apart ( as anyone can tell from some of the "likes" I "click"..but seriously , your stubborness on things that others know more about than you, or who have differing but equaly valid viewpoints on, would try the patience of a saint.Not an "attack", it's what I'd say to you if we were having a drink, you post some great stuff, very interesting and informative, and some like this.Go and plane something.

 

[Phil Pascoe]

Now some slate comes from Portugal, most is imported from India* ( as is the case with a huge amount of "decorative stone" ) ...

I knew a chap who imported granite headstones from China because they were cheaper than than home produced ones ..................................... and he owned a quarry.

 

[Daniel2]

...Snip
No wonder pyramids took so long to build if they were hanging around waiting for frosts all the time!

Especially in Egypt.
I don't think it freezes very often there.

 

[Misterdog]

Yes. Have you seen any particular evidence of this with roofs, caused by moss?

Show your evidence that the moss causes no harm.






Thought not.

 

[Misterdog]

Especially in Egypt.
I don't think it freezes very often there.

Higher altitude up mountains and clear night skies ?

Some mountainous locations in Sinai, such as Saint Catherine, have cooler night temperatures, due to their high elevations. It usually snows on the Sinai mountains,

There appears to be a distinct lack of Geographical/Geological knowledge on here.
Maybe science generally.

Maybe best stick to woodworking.

Though this is the internet so any old opinion is worthy of a mention - as fact.

 

[Jacob]

Yes..We live in an area with 99% of the houses having slate roofs ( Brittany ). In Ireland a large part of my home area had / has slate roofs.I know Wales very well, most of the houses in North Wales have / had slate roofs.
When you re-roof with slate , you remove the old ones ( I have done this many times ) where there was moss on the old ones , when you remove the moss, the slates show pitting , splits , and "flaking" damage.Unless your slate roof has been damaged by hailstorms or other percussive events, the absolute top reason for repairing it or replacing it is due to damage and or breaking of or displacement of slates due to moss damage.

Jacob..put down the spade and quit digging, you are making yourself look stupid in the face of the wide experience" of others here in the matter, I only posted this so as to avoid anyone falling for your usual stubbornness ( on this subject ) in the face of facts ( which does you no favours ) , anyone with a slate or tile roof following your thinking on the subject of moss on roofs would have to deal with the effects of moss damage long after you were gone.

Yes it looks picturesque ( I am a professional artist / sculptor , have been for 50 years ) but the charm ceases when a slate or a tile comes off or is broken due to moss damage and your roof leaks.My immediate neighbours had to replace their slate roof 5 years ago, the cost was horrific, nearly 25% of what they paid for the house.
We are in an area of slate quarries ( all now closed ), I also know the slate quarries at Festiniog very well ( I think most , if not all of of them are now closed for roofing slate supplies, I used to buy slate discs by the tens of thousands from them for screen printing my designs on back in the 70s and 80s, I've talked at length with slate quarriers in both Wales and Brittany. Now some slate comes from Portugal, most is imported from India* ( as is the case with a huge amount of "decorative stone" ) when you go the now non working quarries , you can see the damage done by moss to the rock in situ, and if you have replaced slates or an entire slate roof because of damage due to moss being left to attack them, you would not be stubbornly talking such bolleaux.

When moss is growing and when it breaks down, it produces acids upon contact with water, said acids attack ( slowly ) whatever it is growing on.

* Not very "green" shipping slate halfway around the world to replace those slates and rooves damaged by allowing moss to grow on slate rooves.

Well I have lived in Wales too and have repaired slate roofs, and yes there may be deterioration of various sorts, but I've never associated it with moss.
Current building 150 years old (Derbyshire) has had original slates relaid, entirely on the north side and partially on the south. The south facing roof gets the weathering from alternating sun and frost, as does the joinery paint work and the rendering.
I think the moss association may be the effect of moss taking root where there are existing fault lines but not necessarily being the cause.
Similarly with other stuff around derelict buildings, even Japanese knotweed - gets blamed for causing the dereliction but in fact is merely occupying space/gaps already made available by building collapse, lost mortar etc.
Had a long chat with local expert whose name I've forgotten (I've got his book on the subject somewhere) who said the same sort of thing when we were looking at tree root damage and possible court case.
But moss can block gutters.

 

[mwinfrance]

Re The pyramids..It gets very cold in the desert* ( where they got the stone from ) at night, freezing ( or below temperatures are a regular occurrence, sometimes multiple times per week, even now with global warming ).

*all deserts, not just those along the north African med coast.Rock splitting ( quarrying ) by various peoples and civilisations pre-dating ours using the volume difference due to the "phase changes" of water to ice is an already proven ( by multiple experiments ) archeological fact.

 

[Jacob]

Show your evidence that the moss causes no harm.






Thought not.

I've taken thick moss layer off corrugated asbestos roof and it was in perfect nick underneath.
Have dislodged it on other places but never clear whether it's a cause or an effect. Which came first, the crack or the moss?
On the other hand seems to be no doubt that south facing gets hit worse than north facing, moss or no moss.

 

[mwinfrance]

Arrrrgh "I think" is not a fact. I can now see why you got banned previously, you just argue for arguements sake.
I pity your missus.

 

[Jacob]

Arrrrgh "I think" is not a fact. I can now see why you got banned previously, you just argue for arguements sake.
I pity your missus.

I'm interested in "memes". There's a lot of them about!

 

[mwinfrance]

I knew a chap who imported granite headstones from China because they were cheaper than than home produced ones ..................................... and he owned a quarry.

We may know the same man, initials RL perchance? Owns quarries across a few countries, major stone importer/ exporter, huge amount of slabs and counter tops and monumental work . Multiple containers loads every day , moving all over the world, also runs some of the most informative websites in the world of stone. His images of different stone are the reference "bible" for those of us who do faux stone finishes and trompe l'oeil stone.

 

[Misterdog]

lost mortar

Does freeze thaw perhaps contribute to the decay of concrete and mortar, or maybe some might think that UV light is the cause.

Pot holes in the roads are also caused by freeze thaw.

 

[Phil Pascoe]

We may know the same man, initials RL perchance?

No.

 

[mwinfrance]

OK.

 

[Jacob]

Does freeze thaw perhaps contribute to the decay of concrete and mortar, or maybe some might think that UV light is the cause.

Pot holes in the roads are also caused by freeze thaw.

Yes to all that and no doubt the Egyptians used frost loosened/split stone much as everybody everywhere does, if available, but they couldn't possibly "quarry rock" by using frost, which is what you originally said. They'd be hanging around for years waiting for each split to occur!
Possibly some confusion with "glacial quarrying"

 

[mwinfrance]

How does one plane if one has ones fingers in ones ears singing "lah lah lah"...reminds me of "flat earthers" etc.

 

[TRITON]

I was under the impression that they first drilled holes, then hammered in wooden stakes, which they then soaked. The water expanded the wood and the pressure from multiple stakes caused the stone to crack*

*If this has been explained earlier in this thread before some nonsense about moss, please ignore.
Unless of course moss was used, as in to keep the stakes wet in a very hot climate.