Connecting to Collections Care

Hello Everyone, 

Our Mediterranean historic house, built between 1930-1932, has clay floor tiles that came from Cuba. These tiles are used inside the house and on screened in porches. We have two issues with the tiles that I'm noticing. First, the tiles around the perimeter of the porch are starting to disintegrate (please see attached photos). These areas of the porch do get wet during heavy rains. We also see this issue inside the house near doorways that have slight water seepage during extremely heavy rainstorms. The second issue is that we're noticing small holes forming on some of the tiles (see photo). I'm assuming that these are caused by air pockets in the clay that have finally burst. To my understanding, I don't believe that the floors have ever been sealed with anything. I've done some quick research online but was wondering what the current best museum practice is to preserve these original tiles?  

Some extra context: We are in central Florida so lots of humidity and rain. No one walks on the porch tiles except for myself and my staff to sweep occasionally. Inside the house, we have carpet runners on parts of the visitor path but not all areas as we want our guests to experience the beautiful patterns created by the tiles. 

Any tips you can provide on current clay tile preservation is greatly appreciated. Thank you. 

Hello Everyone, 

Our Mediterranean historic house, built between 1930-1932, has clay floor tiles that came from Cuba. These tiles are used inside the house and on screened in porches. We have two issues with the tiles that I'm noticing. First, the tiles around the perimeter of the porch are starting to disintegrate (please see attached photos). These areas of the porch do get wet during heavy rains. We also see this issue inside the house near doorways that have slight water seepage during extremely heavy rainstorms. The second issue is that we're noticing small holes forming on some of the tiles (see photo). I'm assuming that these are caused by air pockets in the clay that have finally burst. To my understanding, I don't believe that the floors have ever been sealed with anything. I've done some quick research online but was wondering what the current best museum practice is to preserve these original tiles?  

Some extra context: We are in central Florida so lots of humidity and rain. No one walks on the porch tiles except for myself and my staff to sweep occasionally. Inside the house, we have carpet runners on parts of the visitor path but not all areas as we want our guests to experience the beautiful patterns created by the tiles. 

Any tips you can provide on current clay tile preservation is greatly appreciated. Thank you. 

Dear Diana,

Our C2CC expert colleagues had a few follow-up questions:
-  Is the grout around the tiles original to the 30's or has it been "updated" at any point?
- are you certain this is a recent problem? Often with buildings, things go unnoticed, until someone notices.
- can you provide  a better definition of "disintegrating?" The surface of the tiles looks rough-is it actually friable?
- can you send high resolution images that one could zoom in on?

Once we receive your response, our colleagues will send some more thoughts on this issue.

All the best,
Luisa
Connecting to Collections Care Monitor

Hello Everyone, 

Our Mediterranean historic house, built between 1930-1932, has clay floor tiles that came from Cuba. These tiles are used inside the house and on screened in porches. We have two issues with the tiles that I'm noticing. First, the tiles around the perimeter of the porch are starting to disintegrate (please see attached photos). These areas of the porch do get wet during heavy rains. We also see this issue inside the house near doorways that have slight water seepage during extremely heavy rainstorms. The second issue is that we're noticing small holes forming on some of the tiles (see photo). I'm assuming that these are caused by air pockets in the clay that have finally burst. To my understanding, I don't believe that the floors have ever been sealed with anything. I've done some quick research online but was wondering what the current best museum practice is to preserve these original tiles?  

Some extra context: We are in central Florida so lots of humidity and rain. No one walks on the porch tiles except for myself and my staff to sweep occasionally. Inside the house, we have carpet runners on parts of the visitor path but not all areas as we want our guests to experience the beautiful patterns created by the tiles. 

Any tips you can provide on current clay tile preservation is greatly appreciated. Thank you. 

Hello Luisa and All, 

I am attaching new photographs that are in a larger format. Unfortunately, I don't have the best of cameras. 

When I say disintegrating, what I am seeing is that some of the tiles are extremely worn and look crumbled or pulverized. I spoke to a colleague who has been here for many years and she said that she believes the issue began when they used to have live potted plants on the porches for the holiday season. This actually would have been in the early 2000s when it began then. As they watered the plants each day the tiles underneath would remain wet as the pots drained. I'm assuming this is what initially caused the problem. We no longer keep live plants on the porches but this may have gone on up until 2018/2019 (I'm not positive on that). Looking back at some older photographs (we don't have many), the tiles have definitely gotten worse over the years. And the issue is only happening in areas that get wet. 

To my understanding, the grout is the original grout from the 30s. There are some areas inside the house that the grout has been touched up but not on the porches.

As far as the small holes I've noticed. Some of them appear to be much older, whereas the crumbled clay inside the holes in others looks brighter indicating to me that the hole is more recent. As you mentioned, these might be the sort of thing that are old and went unnoticed but because I'm super focused on it right now I'm just noticing them more. 

I found documentation suggesting that the "disintegrating" tiles should be removed and replaced but that never happened. Our president has asked me what we can do to prevent further issues and to preserve/improve the look of the ones with condition issues. So, here I am :) 

Thank you, 
Diana

Dear Diana,

Our C2CC expert colleagues had a few follow-up questions:
-  Is the grout around the tiles original to the 30's or has it been "updated" at any point?
- are you certain this is a recent problem? Often with buildings, things go unnoticed, until someone notices.
- can you provide  a better definition of "disintegrating?" The surface of the tiles looks rough-is it actually friable?
- can you send high resolution images that one could zoom in on?

Once we receive your response, our colleagues will send some more thoughts on this issue.

All the best,
Luisa
Connecting to Collections Care Monitor

Hello Everyone, 

Our Mediterranean historic house, built between 1930-1932, has clay floor tiles that came from Cuba. These tiles are used inside the house and on screened in porches. We have two issues with the tiles that I'm noticing. First, the tiles around the perimeter of the porch are starting to disintegrate (please see attached photos). These areas of the porch do get wet during heavy rains. We also see this issue inside the house near doorways that have slight water seepage during extremely heavy rainstorms. The second issue is that we're noticing small holes forming on some of the tiles (see photo). I'm assuming that these are caused by air pockets in the clay that have finally burst. To my understanding, I don't believe that the floors have ever been sealed with anything. I've done some quick research online but was wondering what the current best museum practice is to preserve these original tiles?  

Some extra context: We are in central Florida so lots of humidity and rain. No one walks on the porch tiles except for myself and my staff to sweep occasionally. Inside the house, we have carpet runners on parts of the visitor path but not all areas as we want our guests to experience the beautiful patterns created by the tiles. 

Any tips you can provide on current clay tile preservation is greatly appreciated. Thank you. 

Dear Diana,
Thank you again.
We received the following message from Lorraine Schnabel and some additional aspects to consider:

"My first instinct is that the mortar is too dense. But this is a 1930's installation, so chances are pretty good it was installed with a dense mortar to begin with. In one of the images the mortar looks as though it might have been replaced, and there does seem to be a little efflorescence along the edge of one joint. If the tiles were repointed, the new mortar could be the problem.

I wonder if anything else about the existing conditions has changed? Are there new drainage challenges? Maybe the area is simply getting more wet, more frequently because the weather has changed? Have other things about the environment changed? Temperatures? It may be that, if the existing mortar is original, it no longer functions well in the current existing conditions. Or, it is possible that the tiles are simply old and are finally breaking down from the ordinary exposure they receive.

The tiles that are there are clearly disintegrating, but the reason why is not clear."

Would you be able to provide some input as to the questions regarding any environmental changes that may be contributing to the deterioration?

All my best,
Luisa
Connecting to Collections Care Monitor

------------------------------
Luisa Casella
Photograph Conservator
West Lake Conservators, Ltd.
Ithaca NY

Original Message:
Sent: 05-04-2023 09:53
From: Diana Welsh
Subject: Disintegrating Clay Tile Floors

Hello Luisa and All, 

I am attaching new photographs that are in a larger format. Unfortunately, I don't have the best of cameras. 

When I say disintegrating, what I am seeing is that some of the tiles are extremely worn and look crumbled or pulverized. I spoke to a colleague who has been here for many years and she said that she believes the issue began when they used to have live potted plants on the porches for the holiday season. This actually would have been in the early 2000s when it began then. As they watered the plants each day the tiles underneath would remain wet as the pots drained. I'm assuming this is what initially caused the problem. We no longer keep live plants on the porches but this may have gone on up until 2018/2019 (I'm not positive on that). Looking back at some older photographs (we don't have many), the tiles have definitely gotten worse over the years. And the issue is only happening in areas that get wet. 

To my understanding, the grout is the original grout from the 30s. There are some areas inside the house that the grout has been touched up but not on the porches.

As far as the small holes I've noticed. Some of them appear to be much older, whereas the crumbled clay inside the holes in others looks brighter indicating to me that the hole is more recent. As you mentioned, these might be the sort of thing that are old and went unnoticed but because I'm super focused on it right now I'm just noticing them more. 

I found documentation suggesting that the "disintegrating" tiles should be removed and replaced but that never happened. Our president has asked me what we can do to prevent further issues and to preserve/improve the look of the ones with condition issues. So, here I am :) 

Thank you, 
Diana

Dear Diana,

Our C2CC expert colleagues had a few follow-up questions:
-  Is the grout around the tiles original to the 30's or has it been "updated" at any point?
- are you certain this is a recent problem? Often with buildings, things go unnoticed, until someone notices.
- can you provide  a better definition of "disintegrating?" The surface of the tiles looks rough-is it actually friable?
- can you send high resolution images that one could zoom in on?

Once we receive your response, our colleagues will send some more thoughts on this issue.

All the best,
Luisa
Connecting to Collections Care Monitor

Hello Everyone, 

Our Mediterranean historic house, built between 1930-1932, has clay floor tiles that came from Cuba. These tiles are used inside the house and on screened in porches. We have two issues with the tiles that I'm noticing. First, the tiles around the perimeter of the porch are starting to disintegrate (please see attached photos). These areas of the porch do get wet during heavy rains. We also see this issue inside the house near doorways that have slight water seepage during extremely heavy rainstorms. The second issue is that we're noticing small holes forming on some of the tiles (see photo). I'm assuming that these are caused by air pockets in the clay that have finally burst. To my understanding, I don't believe that the floors have ever been sealed with anything. I've done some quick research online but was wondering what the current best museum practice is to preserve these original tiles?  

Some extra context: We are in central Florida so lots of humidity and rain. No one walks on the porch tiles except for myself and my staff to sweep occasionally. Inside the house, we have carpet runners on parts of the visitor path but not all areas as we want our guests to experience the beautiful patterns created by the tiles. 

Any tips you can provide on current clay tile preservation is greatly appreciated. Thank you. 

Hello Everyone, 

Our Mediterranean historic house, built between 1930-1932, has clay floor tiles that came from Cuba. These tiles are used inside the house and on screened in porches. We have two issues with the tiles that I'm noticing. First, the tiles around the perimeter of the porch are starting to disintegrate (please see attached photos). These areas of the porch do get wet during heavy rains. We also see this issue inside the house near doorways that have slight water seepage during extremely heavy rainstorms. The second issue is that we're noticing small holes forming on some of the tiles (see photo). I'm assuming that these are caused by air pockets in the clay that have finally burst. To my understanding, I don't believe that the floors have ever been sealed with anything. I've done some quick research online but was wondering what the current best museum practice is to preserve these original tiles?  

Some extra context: We are in central Florida so lots of humidity and rain. No one walks on the porch tiles except for myself and my staff to sweep occasionally. Inside the house, we have carpet runners on parts of the visitor path but not all areas as we want our guests to experience the beautiful patterns created by the tiles. 

Any tips you can provide on current clay tile preservation is greatly appreciated. Thank you. 

Hello Everyone, 

Our Mediterranean historic house, built between 1930-1932, has clay floor tiles that came from Cuba. These tiles are used inside the house and on screened in porches. We have two issues with the tiles that I'm noticing. First, the tiles around the perimeter of the porch are starting to disintegrate (please see attached photos). These areas of the porch do get wet during heavy rains. We also see this issue inside the house near doorways that have slight water seepage during extremely heavy rainstorms. The second issue is that we're noticing small holes forming on some of the tiles (see photo). I'm assuming that these are caused by air pockets in the clay that have finally burst. To my understanding, I don't believe that the floors have ever been sealed with anything. I've done some quick research online but was wondering what the current best museum practice is to preserve these original tiles?  

Some extra context: We are in central Florida so lots of humidity and rain. No one walks on the porch tiles except for myself and my staff to sweep occasionally. Inside the house, we have carpet runners on parts of the visitor path but not all areas as we want our guests to experience the beautiful patterns created by the tiles. 

Any tips you can provide on current clay tile preservation is greatly appreciated. Thank you. 

Hello Everyone, 

Our Mediterranean historic house, built between 1930-1932, has clay floor tiles that came from Cuba. These tiles are used inside the house and on screened in porches. We have two issues with the tiles that I'm noticing. First, the tiles around the perimeter of the porch are starting to disintegrate (please see attached photos). These areas of the porch do get wet during heavy rains. We also see this issue inside the house near doorways that have slight water seepage during extremely heavy rainstorms. The second issue is that we're noticing small holes forming on some of the tiles (see photo). I'm assuming that these are caused by air pockets in the clay that have finally burst. To my understanding, I don't believe that the floors have ever been sealed with anything. I've done some quick research online but was wondering what the current best museum practice is to preserve these original tiles?  

Some extra context: We are in central Florida so lots of humidity and rain. No one walks on the porch tiles except for myself and my staff to sweep occasionally. Inside the house, we have carpet runners on parts of the visitor path but not all areas as we want our guests to experience the beautiful patterns created by the tiles. 

Any tips you can provide on current clay tile preservation is greatly appreciated. Thank you. 

Dear Diana,

I meant to offer my suggestion earlier but held back because all I have is several decades of experience but not specialized training in architectural materials and hoped someone with specific knowledge would chime in.

Making terra cotta tiles (and the floors at my home) involves a low-fire process and is usually done in a makeshift wood fire kiln. Characteristically the individual tiles don't receive even heat and only the lucky ones get sufficient heat and time to vitrify as intended. Making the tiles also frequently resulted in inclusions of stones and lose material containing bubbles, which resulted in voids as your photos illustrate. The friable areas bear witness to the effects of time, the elements, and inherent vice on these tiles.

Unless my suggestion below receives disapproval and objection from experts in the field, I recommend trying in an inconspicuous area a ~10% solution of Sodium Silicate (water-glass). The solution upon drying will fill some of the voids between the clay particles and act as a waterproof binder. The process can be repeated if necessary, but I would be cautious to not seal the surface with a layer of water-glass, as that would alter the way the clay reacts to changes of humidity and temperature and may result in further spalting.

Good luck,

George

Hello Everyone, 

Our Mediterranean historic house, built between 1930-1932, has clay floor tiles that came from Cuba. These tiles are used inside the house and on screened in porches. We have two issues with the tiles that I'm noticing. First, the tiles around the perimeter of the porch are starting to disintegrate (please see attached photos). These areas of the porch do get wet during heavy rains. We also see this issue inside the house near doorways that have slight water seepage during extremely heavy rainstorms. The second issue is that we're noticing small holes forming on some of the tiles (see photo). I'm assuming that these are caused by air pockets in the clay that have finally burst. To my understanding, I don't believe that the floors have ever been sealed with anything. I've done some quick research online but was wondering what the current best museum practice is to preserve these original tiles?  

Some extra context: We are in central Florida so lots of humidity and rain. No one walks on the porch tiles except for myself and my staff to sweep occasionally. Inside the house, we have carpet runners on parts of the visitor path but not all areas as we want our guests to experience the beautiful patterns created by the tiles. 

Any tips you can provide on current clay tile preservation is greatly appreciated. Thank you. 

George (and Diana),

Given the date of this building, the quarry tiles could have been manufactured in the way you describe, but they also could have been high quality extruded products fired at high temperature. Just because they are disintegrating does not mean they were low fired or low quality. That is why additional questions were asked about the existing conditions. The climate has changed since these tiles were installed, particularly as regards intensities and amounts of precipitation in places like Florida. A closer examination by someone with a trained eye of both the existing conditions of the installation and the local drainage conditions around the building is in order to make sure there is nothing implicated in the broader picture.

The tiles may also have been finished at some point, thought there is no institutional memory of this, and a finish could be a contributing factor in their deterioration. 

Consolidation of any sort would not be recommended for fired clay units in regular contact with moisture that are already disintegrating. Particularly using a product that added sodium to a system where there already appear to be salts based on the images provided. It may be that these tiles have reached the end of their service life (at close to 100 years) and they may need to be replaced, but as with other types of materials, treatments shouldn't be implemented without a clearer understanding of the current character and properties of the material and appropriate preliminary testing.

Consultation with an architectural conservator would be the best course, especially if there is a desire to preserve currently undamaged tile in the same location.

Kind regards,

Dear Diana,

I meant to offer my suggestion earlier but held back because all I have is several decades of experience but not specialized training in architectural materials and hoped someone with specific knowledge would chime in.

Making terra cotta tiles (and the floors at my home) involves a low-fire process and is usually done in a makeshift wood fire kiln. Characteristically the individual tiles don't receive even heat and only the lucky ones get sufficient heat and time to vitrify as intended. Making the tiles also frequently resulted in inclusions of stones and lose material containing bubbles, which resulted in voids as your photos illustrate. The friable areas bear witness to the effects of time, the elements, and inherent vice on these tiles.

Unless my suggestion below receives disapproval and objection from experts in the field, I recommend trying in an inconspicuous area a ~10% solution of Sodium Silicate (water-glass). The solution upon drying will fill some of the voids between the clay particles and act as a waterproof binder. The process can be repeated if necessary, but I would be cautious to not seal the surface with a layer of water-glass, as that would alter the way the clay reacts to changes of humidity and temperature and may result in further spalting.

Good luck,

George

Hello Everyone, 

Our Mediterranean historic house, built between 1930-1932, has clay floor tiles that came from Cuba. These tiles are used inside the house and on screened in porches. We have two issues with the tiles that I'm noticing. First, the tiles around the perimeter of the porch are starting to disintegrate (please see attached photos). These areas of the porch do get wet during heavy rains. We also see this issue inside the house near doorways that have slight water seepage during extremely heavy rainstorms. The second issue is that we're noticing small holes forming on some of the tiles (see photo). I'm assuming that these are caused by air pockets in the clay that have finally burst. To my understanding, I don't believe that the floors have ever been sealed with anything. I've done some quick research online but was wondering what the current best museum practice is to preserve these original tiles?  

Some extra context: We are in central Florida so lots of humidity and rain. No one walks on the porch tiles except for myself and my staff to sweep occasionally. Inside the house, we have carpet runners on parts of the visitor path but not all areas as we want our guests to experience the beautiful patterns created by the tiles. 

Any tips you can provide on current clay tile preservation is greatly appreciated. Thank you. 

George (and Diana),

Given the date of this building, the quarry tiles could have been manufactured in the way you describe, but they also could have been high quality extruded products fired at high temperature. Just because they are disintegrating does not mean they were low fired or low quality. That is why additional questions were asked about the existing conditions. The climate has changed since these tiles were installed, particularly as regards intensities and amounts of precipitation in places like Florida. A closer examination by someone with a trained eye of both the existing conditions of the installation and the local drainage conditions around the building is in order to make sure there is nothing implicated in the broader picture.

The tiles may also have been finished at some point, thought there is no institutional memory of this, and a finish could be a contributing factor in their deterioration. 

Consolidation of any sort would not be recommended for fired clay units in regular contact with moisture that are already disintegrating. Particularly using a product that added sodium to a system where there already appear to be salts based on the images provided. It may be that these tiles have reached the end of their service life (at close to 100 years) and they may need to be replaced, but as with other types of materials, treatments shouldn't be implemented without a clearer understanding of the current character and properties of the material and appropriate preliminary testing.

Consultation with an architectural conservator would be the best course, especially if there is a desire to preserve currently undamaged tile in the same location.

Kind regards,

Dear Diana,

I meant to offer my suggestion earlier but held back because all I have is several decades of experience but not specialized training in architectural materials and hoped someone with specific knowledge would chime in.

Making terra cotta tiles (and the floors at my home) involves a low-fire process and is usually done in a makeshift wood fire kiln. Characteristically the individual tiles don't receive even heat and only the lucky ones get sufficient heat and time to vitrify as intended. Making the tiles also frequently resulted in inclusions of stones and lose material containing bubbles, which resulted in voids as your photos illustrate. The friable areas bear witness to the effects of time, the elements, and inherent vice on these tiles.

Unless my suggestion below receives disapproval and objection from experts in the field, I recommend trying in an inconspicuous area a ~10% solution of Sodium Silicate (water-glass). The solution upon drying will fill some of the voids between the clay particles and act as a waterproof binder. The process can be repeated if necessary, but I would be cautious to not seal the surface with a layer of water-glass, as that would alter the way the clay reacts to changes of humidity and temperature and may result in further spalting.

Good luck,

George

Hello Everyone, 

Our Mediterranean historic house, built between 1930-1932, has clay floor tiles that came from Cuba. These tiles are used inside the house and on screened in porches. We have two issues with the tiles that I'm noticing. First, the tiles around the perimeter of the porch are starting to disintegrate (please see attached photos). These areas of the porch do get wet during heavy rains. We also see this issue inside the house near doorways that have slight water seepage during extremely heavy rainstorms. The second issue is that we're noticing small holes forming on some of the tiles (see photo). I'm assuming that these are caused by air pockets in the clay that have finally burst. To my understanding, I don't believe that the floors have ever been sealed with anything. I've done some quick research online but was wondering what the current best museum practice is to preserve these original tiles?  

Some extra context: We are in central Florida so lots of humidity and rain. No one walks on the porch tiles except for myself and my staff to sweep occasionally. Inside the house, we have carpet runners on parts of the visitor path but not all areas as we want our guests to experience the beautiful patterns created by the tiles. 

Any tips you can provide on current clay tile preservation is greatly appreciated. Thank you.