General: Granite

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- CommentAuthorrichy
- CommentTimeFeb 8th 2010
Granite tiles, granite work tops.....discuss!
- CommentAuthorSolidWallJim
- CommentTimeFeb 9th 2010
From a socio/environmental persecptive: If they're cheap, then they're likely to have come from a quarry where people are exploited, health and safety of workers ignored and the environment trashed. India's a common place for kitchen work-tops, so lots of shipping across the world isn't especially green.

But on the plus side, they're shiny, probably last forever if large weights aren't dropped on them. Not sure of their scratch resistance though - probably pretty good if used for work tops.

I think shiny black granite tiles can look a bit "tacky" too - a bit "BLING"

Is Corian for work surfaces a more eco alternative?
- CommentAuthorSteamyTea
- CommentTimeFeb 9th 2010
If your talking economic sustainability here then I think granite is pretty good, but I do live in Cornwall (though Truro Cathedral was refurbished with Chinese Granite).
If your talking environmental sustainability then the 'granite miles' become important as well as the local environmental damage.
As for social sustainability, if a tacky black kitchen top makes people feel good then it is good (for them).
Personally I don't like granite worktops, too easy to break a glass on them.
I would think that ICE would have the embodied energy for granite and Corian, but my copy is at home, and I am not.
- CommentAuthorbiffvernon
- CommentTimeFeb 9th 2010
Posted By: SolidWallJimblack granite
Wearing my geologist's (hard) hat, that's an oxymoron. Granite is the igneous rock dominated by light coloured minerals, quartz and feldspar. If it's black it might be gabbro, dolerite or basalt.

In Creetown, Galloway, there's a large sculpture, by a Japanese artist, in the town square commemorating the town's history of granite quarrying (Liverpool docks were built from the stuff) and there is still a large hill made of the stuff overlooking the town. Plenty more of it available for a zillion kitchen worktops.

The sculpture is made of granite from China; importing it from the other side of the world was cheaper than digging it up from a few hundred yards away.
- CommentAuthorbiffvernon
- CommentTimeFeb 9th 2010
Some more on Hideo Furata and creetown granite:

http://www.ginkgoprojects.co.uk/projects/?id=1085
- CommentAuthorowlman
- CommentTimeFeb 9th 2010
On a few occasions I've used the man made stone tiles and worktops, ( Crushed granite, marble, quarz, etc in a resin binder). Came from Italy and I guess was, in the main quarry waste, sort of a stone MDF.
- CommentAuthorrichy
- CommentTimeFeb 9th 2010
I do like granite tiles and worktops. I like the man made version too. Does anyone know more about the process used to produce a blingy shiney reconstituted granite top?
- CommentAuthorowlman
- CommentTimeFeb 10th 2010
The Italians in particular, and I think the Spanish, have the reconstituted stone business off to a fine art. I think its cast in huge blocks and then put through multiple diamond saws to produce sheets of whatever thickness. and then polished. The blingey bits I guess are possibly stainless or nickel micro-shards rather like the metal powders that are used in cold cast bronze sculpting/moulding. I guess the trade secret is getting the even distibution in the mix. They've been at it for years, thats how they achieve the even mixtures of aggregates in the tiles etc.

Mike
- CommentAuthorSolidWallJim
- CommentTimeFeb 10th 2010 edited
Posted By: biffvernon
Posted By: SolidWallJimblack granite
Wearing my geologist's (hard) hat, that's an oxymoron.
blockquote>

Sorry Biff - I should know better too having spent wind-swept days on Dartmoor on geology field trips!

I think the acceptable phrase for black granite flogged in kitchen shops is "Commercical Granite"
- CommentAuthorTuna
- CommentTimeFeb 10th 2010
Do you have to factor in the shorter lifespans of the glasses you break on the stuff? It can still stain and mark as well. Horses for courses though.

Much prefer wooden worktops. They're not bomb proof, but at least they grow on trees.
- CommentAuthorSteamyTea
- CommentTimeFeb 16th 2010
Corian is an acrylic (like perspex) so can stain but it is possible to polish scratches out. Granite is one way of incorporating thermal mass into your house, so may have its place.
- CommentAuthorjolly-green-giant
- CommentTimeFeb 16th 2010
reserch your source no chemicals used to make granate onl;y water yes has millage try 20mm granite on 20mm marine ply with 20 mm noseing cuts down on weight and looks just as good granite is very hard to stain if you choose black it is hard to keep clean water marks ect
plus side will out last your kitchen can withstand direct heat so you can put hot dishes on it no problems
the shine comes from finishing process the real shiney granite is polished more and so cost more
tip never allow installer to gring granite in your house for final fitting you would not belive the mess it makes
the work top will cost from £150 to £400plus a linear meter noseing profiles add even more so it not a cheap option j-g-j
- CommentAuthorSolidWallJim
- CommentTimeFeb 16th 2010
"tip never allow installer to grind granite in your house for final fitting you would not belive the mess it makes"

And granite dust isn't particularly great for the lungs either!
- CommentAuthorPaul in Montreal
- CommentTimeFeb 16th 2010
Posted By: SteamyTeaGranite is one way of incorporating thermal mass into your house, so may have its place.
But it is lower thermal mass per unit volume than wood. Anyway, the tiny amount of thermal mass of a countertop is essentially irrelevant.

Posted By: SteamyTeaCorian is an acrylic (like perspex) so can stain
Worse is that it can get burn/scorch marks on it which cannot be polished out.

Paul in Montreal ( with wooden countertops)
- CommentAuthormike7
- CommentTimeFeb 16th 2010
Posted By: Paul in MontrealBut it is lower thermal mass per unit volume than wood.

Not what one would expect, and not according to my sources:- approx 2.2.10^6 J/m^3.K for stone cf approx 1.2.10^6 for wood.
- CommentAuthorPaul in Montreal
- CommentTimeFeb 16th 2010 edited
I was thinking of concrete and wood - they're both of the same order of magnitude. See also http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=4273
- CommentAuthorbiffvernon
- CommentTimeFeb 17th 2010
No way, unless it was some light weight aerated concrete.
- CommentAuthorPaul in Montreal
- CommentTimeFeb 17th 2010
Posted By: biffvernonNo way, unless it was some light weight aerated concrete.

Concrete is around 750-880 J/kg·K and wood is around 1800-2200.

Concrete is around 2.2 to 2.4 cg/cm3 and wood is up to around1.09 (depending on the species).

So if we say 2.3 for concrete then it's about 1725 J/m3/K and nice hardwood is around 2000 ish - ie within about 10% of each other.

Figures from various sources, including http://www.engineeringtoolbox.com/specific-heat-solids-d_154.html and http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=4313

Paul in Montreal.
- CommentAuthormike7
- CommentTimeFeb 18th 2010
Interesting to look at the effect of moisture content of wood on the volumetric spec. heat:-

If my sums are right - see below - a small (+20%) change in timber moisture content has a large effect on volumetric spec heat (+61%). Which means one needs to be careful with the data used. The usual figure I've seen quoted for air dried wood is 20%, and I've a notion that depending on heating etc one might expect 8 or 10% in internal woodwork?

I had a figure of 1700 J/Kg/K for the mass spec. heat of some wood (can't recall what) and a density of 700Kg/m3 which gave me my vol spec heat of 1.19 .10^6 J/m3.Lets suppose it was quite dry, ie. 0% moisture.

The same wood if it had moisture of 20% of dry weight would have a density now of 840 (if you'll allow me to ignore any swelling) and a mass spec heat of 1700 plus 0.14 times the spec ht of water (4200) = 1700+588 = 2288. That gives a new vol spec heat of .84 x 2288 ie. 1.92 .10^6 J/m3/K, or 61% increase on the figure for when dry. Well I never.
- CommentAuthorbiffvernon
- CommentTimeFeb 18th 2010 edited
Posted By: Paul in Montrealwood is up to around1.09 (depending on the species).
1.09? Odd stuff like ironwood perhaps, but most wood floats!
- CommentAuthorludite
- CommentTimeFeb 18th 2010
granite work tops are maybe a little like the emperors new clothes - we have massive buildings made out of massive rocks of granite - but if u want a small flat piece as a worktop in your kitchen it's gonna cost loads more. . . .

may I refer you to photos of my fire hearth on various other threads - made from a (second hand) single kitchen island unit worktop - works brilliantly as a hearth but I wouldn't have it as a countertop - cold - smashes glasses - have heard it can break if its cold and you put a hot pan on it. . . . . . .. and, if its highly polished, you can't tell if u have spills on it. . . . .. .

if i had the money i think i'd go for corian (or similar) but have opted for a cheap laminate instead. . . .
- CommentAuthorbiffvernon
- CommentTimeFeb 18th 2010
The almighty Wiki has a table of building materials here: http://en.wikipedia.org/wiki/Specific_heat_capacity
- CommentAuthorPaul in Montreal
- CommentTimeFeb 18th 2010
Posted By: biffvernon1.09? Odd stuff like ironwood perhaps, but most wood floats!
I know - but the figure I used was from a previous thread and was specific to some flooring I'd used where I was comparing the thermal mass versus concrete. But wood has a high specific heat capacity because of the cellulose in it and the associated hydrogen bonds between all those -OH groups (same for water too).

Paul in Montreal.
- CommentAuthorrichy
- CommentTimeFeb 18th 2010
Great advice from Jolly Green G. Thanks.

So can anyone put me in touch with a supplier of granite with good Karma at a reasonable price?

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