Help! sealant on sandstone stained and peeled - Acrylic polymer made for freeze_thaw

[Shona]

Thank you, Tony, for your descriptions of the photos. I had no idea that the black 'stuff' and dendrite looking shapes was iron. I thought I had read that the dots at least was fungus. The second to last photo was included to show burn spots on flagstone and sand joints from crop burner. Also with regard to the sealant, I am aware of some of the various types, and after my inquiry I was told that the polymer that would be used would be a penetrating polymer. It seems with the tests I did that it penetrated the sand but remained on the surface of some of the stones, occurring more often on the lighter color flags (maybe due to increased hardness)?
Again, thanks Tony for commenting on the photos, and thanks EVERYONE for your interest in helping and all your questions and comments.
Shona

[Shona]

George, thank you very much for allaying my fears of leaving the sealant on over winter. Our climate in Utah is VERY DRY so mortar is not used that much in patios, since it cracks so quickly. So....the joints are filled with sand, and the flags are on a roadbase (gravel) base and then sand. I will do more research as you suggest, on the various products that would be good for our climate. It gets VERY HOT in the summer so we have large variations in the fall, spring and winter in temperature....thus the 'freeze-thaw' cycle we call it. And yes, I'm not too fond of the extreme 'wet' look, just some basic protection against stains from bbq, leaf fall, berries, budgies, etc. Thanks again, George, for taking the time to encourage me and give your advice.

[London Stone Paving]

The Sealant oracle (Roger) will be able to advise on the best way of removing sealant. Do you get really harsh winters in your area? The reason I ask is because I am wondering why you have chosen to seal the stone. Naturally riven stone is generally quite hardy stuff and unless its laid in an area where it is likely to get stained (like under a berry bush or fruit tree for example) or you have some seriously harsh winters in your area, I would say that it might not need to be sealed

[PavingSuperstore]

Hi Shona,

I cannot really advise on any impact on the base as it's not the way we would lay paving here, but certainly speaking for the stone, the worst that would happen would be it becoming slightly grubby over Winter and needing a clean before resealing. Normally sealing is to protect the stone anyhow, so I wouldn't think the base would have any bearing on this.

Regards,

George

[lutonlagerlout]

shona ,i am interested in their laying technique
we lay on a strong mortar bed of 40-60mm of 6:1 grit sand:cement
then point
its pretty much bullet proof for uk climate if it has a decent subbase (100mm type 1 stone)
how long did the job take?
how big was it?
have you got a big picture?
all the best
LLL

[RAPressureWashing]

Shona

Just had a look at the product on line, it is acrylic based so should be easy to remove. You have a couple of choices,
1 leave it over winter, it isn't going to get any worse and it isn't going to get any better, but the cold will/could help break it down, seeing as a poor job has been done to start with.

2 if you need to do this, this year I can recommend some products that you have over there to use to get the sealer off.
Will you be doing this or the contractor?
I can also give you a list of tools needed.

If the paving is not sealed this side of spring it isn't going to do any damage to it, expect just get a bit dirty etc.
I don't think you suffer with algae etc like we do over here.

If the sand is still soft to the touch after sealing then this area of sealing has failed as well.
Are you saying the joins are just sand filled? what type of sand was used out of interest. This will need to all come out, sorry as it is not going to cure now really and you would only want to reseal on fresh dry sand.
For me this is a start again type job, remove sealer, get the never drying sand out re-clean the paving, allow it to dry naturally say 24-48 hours with no rain or dampness then if you have to use sand to fill the joins, when re-sanding making sure that the surface is clean of any, and I do mean any sand grains after re-sanding, then re-seal.

[Shona]

Hi LLL, George, and thank you all for responding. I am waiting for Roger to give some advice re: removing the polymer. One thing I am concerned about is the moisture that may have been trapped underneath and causing the stone to crack. I hope it doesn't crack. LLL: I sent photos to Tony that show the scale of the job and the overview of the flags that are still milky white and cracked. I hope he posts them for you. I lived in the Seattle, WA area for 20 years, which has a similar climate to most of UK so I know somewhat about the different situations with regard to weather, however, I must say that at least in the US, our weather is changing in some respects (without getting political here about weather, LOL). The humidity here in Utah is about 8 - 15 or 20% usually. Now we are getting more like 20 - 50% sometimes, but most of the time it is very dry. Some contractors use concrete as a base but others use the gravel so that the patio can 'breathe' more. As I said we have a strong freeze-thaw cycle. Our winters are a bit warmer, and our zone for horticulture changed a little (warmer) but largely we can get to 5 or 10 degrees below zero at times, but most of the time we are down to 10 or 20 degrees F. Anyway, I chose to seal because my husband requested it....he likes the look, but I like natural. I wanted to protect the flags (since we saved in order to do this and value our new patio very much and want to care for it) from bbq oil and fat, and we have a Concord grape near one corner and a Canada Red Chokecherry in the design (as you will see when Tony posts the photos). I didn't calculate the hours, since our installer came after his other job on weekdays and on some Sundays he worked. I can't guess really. He did much cutting of the flags in order to have less than 2" gaps between the flags. He had another worker with him at times. We used a bit less than 4" sub base (roadbase gravel) and about 2" or less sand under flags, and the flags are 1.5 - 2" thick. I hope I answered your questions. I need to get to my oil painting now. Do you folks use a commercial cleaner when you clean sandstone? I have read some blogs and forums that recommend white vinegar or hmmmm sorry I forgot the other inexpensive household item. Thank you. Shona

[Shona]

Hi Roger. I just saw your response. Most of the sand is hard from the acrylic polymer. There are only a few, very few spots where the sand is soft, I would say a total of about 10 inches....just a very few spots. The contractor guaranteed his work, so I HOPE he will do this. So far he is trying to make money before winter sets in. We haven't received any further commitment from him. I am happy to do this myself if I have to. I am an artist, LOL, but not a contractor. I did a rock/pebble mosaic in sand and sealed it at the same time as the patio and it is holding strong. The sand used was coarse masonry sand. I don't know any other way to describe the sand and yes, the joints are ONLY sand. Did you look up the Interlockpro product? Thank you again. Shona Oh, one more thing, do I need to take the acrylic off now so it is not trapping moisture in the stone? I am assuming the product failed because the denser stone where the product didn't penetrate may have been holding more moisture. He should have done a moisture test, and I only learned of this test after this happened. I should have figured out the test because we did cover the flags with a tarp one day and when removing the tarp the 'dry' stones showed the moisture coming up. So I should have placed a small tarp over some of the flags for a day or some hours, then removed it to test for moisture. It seemed to me that he didn't know how to tell if the job was dry enough to apply the polymer. Again, I'm sorry for the confusion since you thought the sand as well didn't hold, but it did in 99.5% of the joints:) Shona

[Shona]

Hi....sorry I posted so much but I have to clear up what may have been a misunderstanding. The way my patio was assembled is not "the way we do patios OVER HERE." The climates across the states, which includes temperature and humidity VARIES TREMENDOUSLY. Here in Utah, especially in the valley, the soil is very clay based, which holds moisture, so there is much movement underneath with the varying of temperature, humidity and precipitation. That is why, in certain areas, CERTAIN installers prefer using the gravel, since it allows for more shifting. The clay, when dry, is very dry and hard, and when moist is very wet and expands greatly and it 'slidey'. So please don't take my situation as a generality about the US installers. The polymer that was used was (they say.....) created for our climates because it was stated that OTHER polymers either seal too much or not enough for our climate. I didn't choose the polymeric sand for various reasons.

Roger, thanks for also mentioning keeping ALL SAND off the flag, because this also happened in spots, and I'm sure this is because a blower was used to take the excess off.

[mickg]

my eyes are bleeding reading this thread, Shona dont take offence but try pressing return twice to start a new paragraph

[RAPressureWashing]

Shona,

There is a way of releasing the moisture, it would mean using Xylene which is fine to use if you know what you are doing, but saying that, from the photos the sealer has peeled off, so a total strip/removal of the sealer is the way forward.

Can you clear one thing up for me, they laid then cleaned the patio used a cop burner to "dry" the patio, THEN did then re-sand then sealed? as the only 10 inch's of soft uncured sand doesn't make sense seeing as the paving has failed I would have thought the sand would have wicked up moisture also but not just in 10 inches.

[lutonlagerlout]

we have a lot of clay here too shona,and it gets down to -10 C now and again
but I am sure local contractors adopt local customs
this stuff that gets poured on the sand and sets it sounds interesting
as above I would leave till the spring

cheers LLL

[RAPressureWashing]

we have a lot of clay here too shona,and it gets down to -10 C now and again
but I am sure local contractors adopt local customs
this stuff that gets poured on the sand and sets it sounds interesting
as above I would leave till the spring

cheers LLL

Over Tony, for sand only stabiliser Resiblock 22 PU though not Acrylic.

[Shona]

Roger, would you kindly re-phrase your question. I don't understand what you mean by saying "not just in 10 inches"? If you mean that you would have thought the sand would have reacted as the pavers did? As I said earlier, we have a base of road base (gravel). There is only about 2" of sand, and remember, if you did go to the website to review the product, you would have seen that the sand has to have a groove above it, that is, it is not flush with the top of the flag. Maybe 3" of sand. Since the acrylic is permeable after it sets, there will be moisture. However, my concern is the moisture BEFORE application and set time.

Roger: the patio was NOT CLEANED before re-sanding and polymer application. Only leaves and things blown off with gas blower.
Again, according to the photos, the sealant only peeled on the Oak Rose and Pink flags and maybe one or two of the Cherokee Red. Tony has more photos if you need. Thanks everyone for your advice. Dear MickG: It is really against my efforts in life to be positive and appreciate others to comment on your post, however, everyone has been so nice here. Please think about why you made the comment to me that you did. I haven't seen any posts like yours. I don't think it was necessary to use the words you did, which were hurtful. Please feel free to not read the post. You can ask me nicely to do something for your convenience, but please refrain from hurtful comments. Everyone here has been so helpful, supportive, and inquisitive. Again, my thanks to all of you and wish you all the best! Shona

[Shona]

Roger: What is the difference, please, if you have time to explain, between using Xylene and stripping entirely? Thank you! Shona