| Author |
Message |
Randall A Chapple, AIA, SE, CCS, LEED AP
Senior Member
Username: rachapple
Post Number: 7
Registered: 12-2005
| | Posted on Monday, October 01, 2007 - 12:33 pm: |    |
Does anyone out there have any experience with using Rosa Verona marble on the exterior of a building? I know that this is typically a no no but we have a limited exposure and may back the stone to increase the stability of the stone.
Thanks |
Dale Roberts CSI, CDT
Senior Member
Username: dale_roberts_csi
Post Number: 34
Registered: 10-2005
| | Posted on Tuesday, October 02, 2007 - 10:32 am: | |
Are you talking about using a direct bond system, like a thin-set installation? over a scratch and brown coat? Or is this going to be mechanically attached? What size are we talking about? |
Marc C Chavez
Senior Member
Username: mchavez
Post Number: 241
Registered: 07-2002
| | Posted on Tuesday, October 02, 2007 - 10:43 am: | |
Of course marble, limestone and travertine are CaC03 and will be harmed by acid rain (a combination of H2S04 and HNO3 acids) but don't completely freak. I'd look at ProSoCo's CONSERVARE. |
Randall A Chapple, AIA, SE, CCS, LEED AP
Senior Member
Username: rachapple
Post Number: 8
Registered: 12-2005
| | Posted on Tuesday, October 02, 2007 - 11:28 am: | |
The stone will be mechanically attached to kerfs in the stone with sealant joints. The size is approximately 4' x 5'. The stone may be epoxied to a backer material. We have a 50' overhang where the stone is located and the stone should only see wetting 4-5 times per year. |
Marc C Chavez
Senior Member
Username: mchavez
Post Number: 242
Registered: 07-2002
| | Posted on Tuesday, October 02, 2007 - 11:46 am: | |
So far back, I'd think you'd be fine. BUT you might seal down near the gound (foot traffic, splash off of concrete etc.) Just a suggestion |
Anne Whitacre, FCSI CCS
Senior Member
Username: awhitacre
Post Number: 651
Registered: 07-2002
| | Posted on Tuesday, October 02, 2007 - 05:14 pm: | |
what about freezing? that may have a bigger impact than simple wetting. in addition, check how sound the marble is. if its not a class A marble you may have problems getting it thin enough to be backed, or supporting it if its not backed. the Marble Institute can tell you more about the marble you have. not every marble can hold together in a 4' x 5' panel.
in addition, I would see how much moisture absorbtion you have, and how high the humidity is in your installation area. if its too high and the marble too absorbtive, it could just slide off the backing no matter what you do. |
Randall A Chapple, AIA, SE, CCS, LEED AP
Senior Member
Username: rachapple
Post Number: 9
Registered: 12-2005
| | Posted on Wednesday, October 03, 2007 - 11:03 am: | |
Thanks for the input. Thermal cycling is a concern as is the marble being a Class C marble. The designer never want to do anything that is easy. |
George A. Everding, AIA, CSI, CCS, CCCA
Senior Member
Username: geverding
Post Number: 357
Registered: 11-2004
| | Posted on Wednesday, October 03, 2007 - 11:17 am: | |
Excuse my ignorance...Class A or Class C marble? Is that defined by the Marble Institute or is it part of the ASTM standard? |
Richard A. Rosen, CSI, CCS, AIA
Senior Member
Username: rarosen
Post Number: 19
Registered: 08-2006
| | Posted on Wednesday, October 03, 2007 - 11:53 am: | |
Another thing you have to be concerned with in marble is hysteresis. The following is from the Arcom Masterspec support document for exterior stone cladding:
"Hysteresis is a term used to describe a phenomenon that affects marble and has been observed in certain white fine-grained crystalline marbles. According to MIA's Dimensional Stone Design - Manual IV, after several cycles of heating and cooling, marble will exhibit a residual expansion of about 20% of the original increase. Marble is also not entirely elastic, but is subject to plastic deformation. Together, these two effects can lead to bowing in thin slabs, which can eventually result in panels cracking and falling off the building. This bowing can also cause minute surface cracking between the calcite crystals, causing them to separate and slough off. This phenomenon is called sugaring because the loose crystals resemble grains of sugar. Sugaring decreases the effective thickness of the panel and leads to further degradation, which will ultimately result in the disintegration of the stone panel. Adequate provision for expansion, which can be twice that of concrete, must be provided if bowing is to be prevented. Prevention also requires using soft joints that will not impart excessive stress into the stone, anchors that will not restrain the stone from expanding, and panels with a thickness-to-length ratio that will provide enough stiffness to resist bowing."
I have seen the resulting bowing and warping of thin marble on the Federal Courthouse in Harrisburgh, PA. All of the veneer on the lower levels of the building had to be replaced when it started to warp an pull itself of of the building. |
Dale Roberts CSI, CDT
Senior Member
Username: dale_roberts_csi
Post Number: 35
Registered: 10-2005
| | Posted on Wednesday, October 03, 2007 - 12:01 pm: | |
Rosa Verona is a class C marble termed by the Marble Institute of America (MIA) it is quarried in Italy. It can be used inside or outside. The groupings A,B,C and D should be taken into account when specifying or using marble. This is particularly true of groups C and D, which may require additional fabrication before or during installation. The basis of this classification is the characteristics encountered in fabricating, and has no reference whatsoever to the comparative merits or value of each type of marble. It will require more maintenance and inspections. Check with the supplier and quarry for their recommendations for this marble.
If available ask for the ASTM C 99 Modulus of Rupture of Dimension Stone. Measuring the modulus of rupture of a stone is a valuable in determining the strength of the stone at its point of attachments with anchoring devices. It also determines the strength of the stone bending. A stone must resist the bending loads, for example between anchor points, from exterior wind loads.
A very similar test is ASTM C 880 for Flexural Strength of Dimension Stone. Similar to ASTM C 99 except the stone is tested at the thickness specified for the project. |
Dale Roberts CSI, CDT
Senior Member
Username: dale_roberts_csi
Post Number: 36
Registered: 10-2005
| | Posted on Wednesday, October 03, 2007 - 12:11 pm: | |
Another ASTM test to look at is ASTM c 97 Absorption and Bulk Gravity of Dimension Stone. This test is used to determine the water absorption and density of stone. It also provides useful information as to the stones’ absorption of liquids and its susceptibility to damage during freezing. |
Anne Whitacre, FCSI CCS
Senior Member
Username: awhitacre
Post Number: 652
Registered: 07-2002
| | Posted on Wednesday, October 03, 2007 - 12:30 pm: | |
as an example, if you use Laticrete for the exterior setting method, they will not warrant an installation if the stone has more than 3% moisture absorption (and like it closer to 2%.)if the stone absorbs too quickly it will take the moisture out of the mortar/setting bed before it has a chance to set up. In addition, high moisture will mean more freezing. with stone, you need to have the test results from the actual block, as moisture absorption can vary in different areas of the same quarry and definitely can vary from different locations and producers of the stone. |
(Unregistered Guest)
Unregistered guest
| | Posted on Wednesday, October 03, 2007 - 11:51 am: | |
Another thing you have to be concerned with in marble is hysteresis. The following is from the Arcom Masterspec support document for exterior stone cladding:
"Hysteresis is a term used to describe a phenomenon that affects marble and has been observed in certain white fine-grained crystalline marbles. According to MIA's Dimensional Stone Design - Manual IV, after several cycles of heating and cooling, marble will exhibit a residual expansion of about 20% of the original increase. Marble is also not entirely elastic, but is subject to plastic deformation. Together, these two effects can lead to bowing in thin slabs, which can eventually result in panels cracking and falling off the building. This bowing can also cause minute surface cracking between the calcite crystals, causing them to separate and slough off. This phenomenon is called sugaring because the loose crystals resemble grains of sugar. Sugaring decreases the effective thickness of the panel and leads to further degradation, which will ultimately result in the disintegration of the stone panel. Adequate provision for expansion, which can be twice that of concrete, must be provided if bowing is to be prevented. Prevention also requires using soft joints that will not impart excessive stress into the stone, anchors that will not restrain the stone from expanding, and panels with a thickness-to-length ratio that will provide enough stiffness to resist bowing."
I have seen the resulting bowing and warping of thin marble on the Federal Courthouse in Harrisburgh, PA. All of the veneer on the lower levels of the building had to be replaced when it started to warp an pull itself of of the building. |
Dale Roberts CSI, CDT
Senior Member
Username: dale_roberts_csi
Post Number: 37
Registered: 10-2005
| | Posted on Friday, October 05, 2007 - 12:07 pm: | |
Hi Anne
There are several other manufactures of thin-set mortars that do not have those requirements for moisture absorption on stone. |
Randall A Chapple, AIA, SE, CCS, LEED AP
Senior Member
Username: rachapple
Post Number: 10
Registered: 12-2005
| | Posted on Tuesday, October 09, 2007 - 12:04 pm: | |
We will be doing full testing on this stone including, compression, flexural, absorption, and we will also do accelerated weathering testing. |
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