Classification scheme - Working group "Natural stones and weathering

WORKING GROUP "NATURAL STONES AND WEATHERING"

Classification scheme of weathering forms

Reference:
FITZNER, B.& HEINRICHS, K. (2002): Damage diagnosis on stone monuments - weathering forms, damage categories and damage indices. In Prikryl, R. & Viles, H. A. (ed.): Understanding and managing stone decay, Proceeding of the International Conference "Stone weathering and atmospheric pollution network (SWAPNET 2001)", 11-56, Charles University in Prague, The Karolinum Press.

LEVEL I

4 GROUPS OF WEATHERING FORMS

LEVEL II

25 MAIN WEATHERING FORMS

LEVEL III

75 INDIVIDUAL WEATHERING FORMS

LEVEL IV

DIFFERENTIATION OF
INDIVIDUAL WEATHERING FORMS ACCORDING TO INTENSITIES

LEVEL I – GROUP OF WEATHERING FORMS
Group 1 - Loss of stone material

LEVEL II

LEVEL III

LEVEL IV

MAIN
WEATHERING FORMS

INDIVIDUAL
WEATHERING FORMS

CLASSIFICATION
OF INTENSITIES
(PARAMETERS)

Back
weathering

Uniform loss of stone material parallel to the original stone surface.

Back weathering due to loss of scales

Uniform loss of stone material parallel to the stone surface due to contour scaling.

Depth of
back weathering
(mm, cm)

sW₁

sW_n

Back weathering due to loss of crumbs / splinters

Uniform loss of stone material parallel to the stone surface due to crumbly disintegration.

uW₁

uW_n

Back weathering due to loss of stone layers dependent on stone structure

Uniform loss of stone material parallel to the stone surface due to exfoliation.

xW₁

xW_n

Back weathering due to loss of crusts

Uniform loss of stone material parallel to the original stone surface due to detachment of crusts with adherent stone material.

cW₁

cW_n

Back weathering due to loss of undefinable stone aggregates / pieces

Uniform loss of stone material parallel to the original stone surface. The type of the preceding detachment of stone material can not be characterized.

zW₁

zW_n

Relief

Morphological change of the stone surface due to partial or selective weathering.

Rounding / notching

Relief by rounding of edges or notching / hollowing out. Concave or convex soft forms.

Depth of
relief
(mm, cm)

Ro₁

Ro_n

Alveolar weathering

Relief in the form of alveolae.
Form comparable to honeycombs.

Ra₁

Ra_n

Weathering out dependent on stone structure

Relief dependent on structural features such as bedding, foliation, banding etc. Frequently striped pattern.

tR₁

tR_n

Weathering out of stone components

Relief due to selective weathering of sensitive stone components (clay lenticles, nodes of limonite etc.) or due to break out of compact stone components (pebbles, fossil fragments etc.). Hole-shaped forms.

Rk₁

Rk_n

Clearing out of stone components

Relief in the form of protruding compact stone components (pebbles, fossil fragments, concretions) due to selective weathering.

Rh₁

Rh_n

Roughening

Finest relief / alteration of gloss due to corrosion or loss of smallest stone particles on smoothed stone surfaces.

Rr₁

Rr_n

Microkarst

Relief due to corrosion, especially on carbonate rocks.

Rm₁

Rm_n

Pitting

Relief in the form of small pits due to biogenically induced corrosion, esp. on carbonate rocks.

Rt₁

Rt_n

Relief due to anthropogenic impact

Relief in the form of scratches etc.

aR₁

aR_n

LEVEL I – GROUP OF WEATHERING FORMS Group 1 – Loss of stone material
LEVEL II		LEVEL III		LEVEL IV
MAIN WEATHERING FORMS		INDIVIDUAL WEATHERING FORMS		CLASSIFICATION OF INTENSITIES (PARAMETERS)
Break out Loss of compact stone fragments.	O	*Break out due to anthropogenic impact* Break out due to war, vandalism etc.	aO	Volume of break out (cm³, dm³) or depth of break out (cm)	aO₁ aO_n
		*Break out due to constructional cause* Break out due to statics, wedge effect of rusting iron etc.	bO		bO₁ bO_n
		*Break out due to natural cause* Break out due to wedgework of roots, earthquakes, intersection of fractures etc.	nO		nO₁ nO_n
		*Break out due to non-recognizable cause*	oO		oO₁ oO_n

LEVEL I – GROUP OF WEATHERING FORMS Group 2 – Discoloration / Deposits
LEVEL II		LEVEL III		LEVEL IV
MAIN WEATHERING FORMS		INDIVIDUAL WEATHERING FORMS		CLASSIFICATION OF INTENSITIES (PARAMETERS)
Discoloration Alteration of the original stone color.	D	*Coloration* Chromatic alteration / coloring due to chemical weathering of minerals (e.g. oxidation of iron and manganese compounds), due to intrusion / accumulation of coloring matter or due to staining by biogenic pigments.	Dc	Degree – change of color	Dc₁ Dc_n
		*Bleaching* Chromatic alteration / decolorization due to chemical weathering of minerals (e.g. reduction of iron and manganese compounds) or extraction of coloring matter (leaching, washing out).	Db		Db₁ Db_n
Soiling Dirt deposits on the stone surface.	I	*Soiling by particles from the atmosphere* Poorly adhesive, mainly grey to black deposits of dust, soot, fly ash etc.	pI	Mass of deposits or degree – covering of the surface	pI₁ pI_n
		*Soiling by particles from water* Poorly adhesive, mainly grey to brown deposits of dust, soil or mud particles.	wI		wI₁ wI_n
		*Soiling by droppings* Deposits of droppings from birds, e.g. from pigeons.	gI		gI₁ gI_n
		*Soiling due to anthropogenic impact* Paint, graffities, posters etc.	aI		aI₁ aI_n

LEVEL I – GROUP OF WEATHERING FORMS Group 2 – Discoloration / Deposits
LEVEL II		LEVEL III		LEVEL IV
MAIN WEATHERING FORMS		INDIVIDUAL WEATHERING FORMS		CLASSIFICATION OF INTENSITIES (PARAMETERS)
Loose salt deposits Poorly adhesive deposits of salt aggregates.	E	*Efflorescences* Poorly adhesive deposits of salt aggregates on the stone surface.	Ee	Mass of deposits or degree – covering of the surface	Ee₁ Ee_n
		*Subflorescences* Poorly adhesive deposits of salt aggregates below the stone surface, e.g. in the zone of detachment of scales.	Ef	Mass of deposits	Ef₁ Ef_n
Crust Strongly adhesive deposits on the stone surface.	C	*Dark-colored crust tracing the surface* Compact deposit, grey- to black-colored, tracing the morphology of the stone surface. Mainly due to deposition of pollutants from the atmosphere.	dkC	For dkC, hkC and fkC: degree – covering of the surface for diC, hiC and fiC: thickness of the crust (mm)	dkC₁ dkC_n
		*Dark-colored crust changing the surface* Compact deposit, grey- to black-colored, changing the morphology of the stone surface. Mainly due to deposition of pollutants from the atmosphere. E.g. gypsum crust with impurities.	diC		diC₁ diC_n
		*Light-colored crust tracing the surface* Compact deposit, light-colored, tracing the morphology of the stone surface. Mainly due to precipation processes. Light-colored crusts of salt minerals, calc-sinter or silica.	hkC		hkC₁ hkC_n
		*Light-colored crust changing the surface* Compact deposit, light-colored, changing the morphology of the stone surface. Mainly due to precipation processes. Light-colored crusts of salt, calc-sinter or silica.	hiC		hiC₁ hiC_n
		*Colored crust tracing the surface* Compact deposit, colored, tracing the morphology of the stone surface. Mainly due to precipation processes. E.g. colored crusts of salt minerals or iron/manganese crusts.	fkC		fkC₁ fkC_n
		*Colored crust changing the surface* Compact deposit, colored, changing the morphology of the stone surface. Mainly due to precipation processes. Eg. colored crusts of salt minerals or iron/manganese crusts.	fiC		fiC₁ fiC_n
Biological colonization Colonization by microorganisms or higher plants.	B	*Microbiological colonization* Colonization by microflora (fungi, algae, lichen) and bacteria. Biofilms.	Bi	Degree – covering of the surface	Bi₁ Bi_n
		*Colonization by higher plants*	Bh		Bh₁ Bh_n

LEVEL I – GROUP OF WEATHERING FORMS Group 2 – Discoloration / Deposits
LEVEL II		LEVEL III		LEVEL IV
MAIN WEATHERING FORMS		INDIVIDUAL WEATHERING FORMS		CLASSIFICATION OF INTENSITIES (PARAMETERS)
Discoloration to crust Transitional form between discoloration (D) and crust (C).	D-C	Coloration to dark-colored crust tracing the surface Transitional form between coloration (Dc) and dark-colored crust tracing the surface (dkC).	Dc-dkC	Degree – covering of the surface	Dc-dkC₁ Dc-dkC_n
		*Coloration to colored crust tracing the surface* Transitional form between coloration (Dc) and colored crust tracing the surface (fkC).	Dc-fkC		Dc-fkC₁ Dc-fkC_n
Soiling to crust Transitional form between soiling (I) and crust (C).	I–C	Soiling by particles from the atmosphere to dark-colored crust tracing the surface Transitional form between soiling by particles from the atmosphere (pI) and dark-colored crust tracing the surface (dkC).	pI-dkC	Degree – covering of the surface	pI-dkC₁ pI-dkC_n
		Soiling by particles from the atmosphere to dark-colored crust changing the surface Transitional form between soiling by particles from the atmosphere (pI) and dark-colored crust changing the surface (diC).	pI-diC	Thickness of the deposit (mm)	pI-diC₁ pI-diC_n
Loose salt deposits to crust Transitional form between loose salt deposits (E) and crust (C).	E–C	Efflorescences to light-colored crust tracing the surface Transitional form between efflorescences (Ee) and light-colored crust tracing the surface (hkC).	Ee-hkC	Degree – covering of the surface	Ee-hkC₁ Ee-hkC_n
		Efflorescences to light-colored crust changing the surface Transitional form between efflorescences (Ee) and light-colored crust changing the surface (hiC).	Ee-hiC	Thickness of the deposit (mm)	Ee-hiC₁ Ee-hiC_n
Biological colonization to crust Transitional form between biological colonization (B) and crust (C).	B-C	*Microbiological colonization to dark-colored crust tracing the surface* Transitional form between microbiological colonization (Bi) and dark-colored crust tracing the surface (dkC).	Bi-dkC	Degree – covering of the surface	Bi-dkC₁ Bi-dkC_n
		*Microbiological colonization to dark-colored crust changing the surface* Transitional form between microbiological colonization (Bi) and dark-colored crust changing the surface (diC).	Bi-diC	Thickness of the deposit (mm)	Bi-diC₁ Bi-diC_n

LEVEL I – GROUP OF WEATHERING FORMS Group 3 – Detachment
LEVEL II		LEVEL III		LEVEL IV
MAIN WEATHERING FORMS		INDIVIDUAL WEATHERING FORMS		CLASSIFICATION OF INTENSITIES (PARAMETERS)
Granular disintegration Detachment of individual grains or small grain aggregates.	G	*Granular disintegration into powder* Detachment of smallest stone particles (stone powder).	Gp	Mass of detaching stone material	Gp₁ Gp_n
		*Granular disintegration into sand* Detachment of small grains as individual grains or small grain aggregates (stone sand).	Gs		Gs₁ Gs_n
		*Granular disintegration into grus* Detachment of larger grains as individual grains or small grain aggregates (stone grus). Especially on granites.	Gg		Gg₁ Gg_n
Crumbly disintegration Detachment of larger compact stone pieces of irregular shape.	P	*Crumbling* Detachment of larger compact stone pieces in the form of crumbs.	Pu	Volume of detaching stone pieces (cm³, dm³) or mass of detaching stone material	Pu₁ Pu_n
		*Splintering* Detachment of larger compact stone pieces in the form of splinters. E.g. on compact carbonate rocks and quartzites.	Pn		Pn₁ Pn_n
		*Crumbling to splintering* Transitional form between crumbling (Pu) and splintering (Pn).	Pu-Pn		Pu-Pn₁ Pu-Pn_n
Flaking Detachment of small, thin stone pieces (flakes) parallel to the stone surface.	F	*Single flakes* Detachment of one layer of flakes parallel to the stone surface.	eF	Mass of detaching stone material	eF₁ eF_n
		*Multiple flakes* Detachment of a stack of flakes parallel to the stone surface.	mF		mF₁ mF_n
Contour scaling Detachment of larger, platy stone pieces parallel to the stone surface, but not following any stone structure.	S	*Scale due to tooling of the stone surface* Detachment of mainly thin scales due to tooling of the stone surface.	qS	Thickness of the scales resp. stack of scales (mm, cm) or mass of detaching stone material	qS₁ qS_n
		*Single scale* Detachment of one layer of scales.	eS		eS₁ eS_n
		*Multiple scales* Detachment of a stack of scales.	mS		mS₁ mS_n

LEVEL I – GROUP OF WEATHERING FORMS Group 3 – Detachment
LEVEL II		LEVEL III		LEVEL IV
MAIN WEATHERING FORMS		INDIVIDUAL WEATHERING FORMS		CLASSIFICATION OF INTENSITIES (PARAMETERS)
Detachment of stone layers dependent on stone structure Detachment of larger stone sheets or plates following the stone structure.	X	*Exfoliation* Detachment of larger stone layers (sheets, plates) following any stone structure (bedding, banding etc.) and the stone surface. Structural feature is oriented parallel to the stone surface.	Xl	Thickness of detaching stone layers resp. stack of layers (mm, cm)	Xl₁ Xl_n
		*Splitting up* Detachment of larger stone layers (sheets, plates) following any stone structure (bedding, banding etc.), but not the stone surface. Structural feature is not oriented parallel to the stone surface.	Xv	Number of detaching stone layers resp. splits	Xv₁ Xv_n
Detachment of crusts with stone material Detachment of crusts with stone material sticking to the crust.	K	Detachment of a dark-colored crust tracing the stone surface	dkK	Mass of detaching material or thickness of detaching layers (mm)	dkK₁ dkK_n
		Detachment of a dark-colored crust changing the stone surface	diK		diK₁ diK_n
		Detachment of a light-colored crust tracing the stone surface	hkK		hkK₁ hkK_n
		Detachment of a light-colored crust changing the stone surface	hiK		hiK₁ hiK_n
		Detachment of a colored crust tracing the stone surface	fkK		fkK₁ fkK_n
		Detachment of a colored crust changing the stone surface	fiK		fiK₁ fiK_n
Granular disintegration to flaking Transitional form between granular disintegration (G) and flaking (F).	G-F	*Granular disintegration into sand to single flakes* Transitional form between granular disintegration into sand (Gs) and single flakes (eF).	Gs-eF	Mass of detaching stone material	Gs-eF₁ Gs-eF_n
		*Granular disintegration into grus to single flakes* Transitional form between granular disintegration into grus (Gg) and single flakes (eF).	Gg-eF		Gg-eF₁ Gg-eF_n

LEVEL I – GROUP OF WEATHERING FORMS Group 3 – Detachment
LEVEL II		LEVEL III		LEVEL IV
MAIN WEATHERING FORMS		INDIVIDUAL WEATHERING FORMS		CLASSIFICATION OF INTENSITIES (PARAMETERS)
Granular disintegration to crumbly disintegration Transitional form between granular disintegration (G) and crumbly disintegration (P).	G-P	*Granular disintegration into sand to crumbling* Transitional form between granular disintegration into sand (Gs) and crumbling (Pu).	Gs-Pu	Mass of detaching stone material	Gs-Pu₁ Gs-Pu_n
		*Granular disintegration into grus to crumbling* Transitional form between granular disintegration into grus (Gg) and crumbling (Pu).	Gg-Pu		Gg-Pu₁ Gg-Pu_n
Flaking to crumbly disintegration Transitional form between flaking (F) and crumbly disintegration (P).	F-P	*Single flakes to crumbling* Transitional form between single flakes (eF) and crumbling (Pu).	eF-Pu	Mass of detaching stone material	eF-Pu₁ eF-Pu_n
		*Single flakes to splintering* Transitional form between single flakes (eF) and splintering (Pn).	eF-Pn		eF-Pn₁ eF-Pn_n
Crumbly disintegration to contour scaling Transitional form between crumbly disintegration (P) and contour scaling (S).	P-S	*Crumbling to single scale* Transitional form between crumbling (Pu) and single scale (eS).	Pu-eS	Mass of detaching stone material or volume of detaching stone pieces (cm³, dm³)	Pu-eS₁ Pu-eS_n
		*Splintering to single scale* Transitional form between splintering (Pn) and single scale (eS).	Pn-eS		Pn-eS₁ Pn-eS_n
Flaking to contour scaling Transitional form between flaking (F) and contour scaling (S).	F-S	*Single flakes to single scale* Transitional form between single flakes (eF) and single scale (eS).	eF-eS	Mass of detaching stone material	eF-eS₁ eF-eS_n
		*Multiple flakes to multiple scales* Transitional form between multiple flakes (mF) and multiple scales (mS).	mF-mS		mF-mS₁ mF-mS_n

LEVEL I – GROUP OF WEATHERING FORMS Group 4 – Fissures / deformation
LEVEL II		LEVEL III		LEVEL IV
MAIN WEATHERING FORMS		INDIVIDUAL WEATHERING FORMS		CLASSIFICATION OF INTENSITIES (PARAMETERS)
Fissures Individual fissures or systems of fissures due to natural or constructional causes.	L	*Fissures independent of stone structure* Individual fissures or systems of fissures independent of structural features such as bedding, foliation, banding etc..	vL	Number of fissures and dimension of fissures – length, width (mm, cm)	vL₁ vL_n
		*Fissures dependent on stone structure* Individual fissures or systems of fissures dependent on structural features such as bedding, foliation, banding etc.	tL		tL₁ tL_n
Deformation Bending / buckling of mainly thin stone slabs due to plastic deformation. Especially on marble slabs.	V	*Deformation, convex*	lV	Amplitude of bending / buckling	lV₁ lV_n
		*Deformation, concave*	rV		rV₁ rV_n