Rebuilding stone porch---how to cure it?
#1
08-06-14, 07:46 AM
Rebuilding stone porch---how to cure it?
Hiya
Supposing I get the thing mortared up and reconstructed, do I need to wrap it up in saran wrap or something, keep it shaded, or what?
It's rock/block/I dunno base, with thick bluestone slabs and so forth. 6X8 surface, couple steps down. I can post pix if it will elucidate anything.
I live in Upstate NY. Currently we are having hot, wet weather. Porch is in sun till afternoon.
ALSO---oops, two threads---planning per some youtube/google info, to mix portland, sand, and probably a plastiiser.
I yam NO expert, but one-quarter Sicilian!
denno
Supposing I get the thing mortared up and reconstructed, do I need to wrap it up in saran wrap or something, keep it shaded, or what?
It's rock/block/I dunno base, with thick bluestone slabs and so forth. 6X8 surface, couple steps down. I can post pix if it will elucidate anything.
I live in Upstate NY. Currently we are having hot, wet weather. Porch is in sun till afternoon.
ALSO---oops, two threads---planning per some youtube/google info, to mix portland, sand, and probably a plastiiser.
I yam NO expert, but one-quarter Sicilian!
denno
#2
08-06-14, 09:55 AM
Group Moderator
You don't want mortar to dry quickly. Dampen the stones so they don't suck the moisture out of the mortar. Shading the area is also a good idea to help prevent it from drying too quickly but in general you don't need to wrap it in plastic. Once the mortar has set a couple hours it's pretty resistant to rain. It may still be soft but it's hardened enough so that rain won't wash it away.
#3
08-06-14, 07:10 PM
Member
You have our sympathy for the Sicilian part. But don't feel too badly, as I'm half Russian. And I don't even like vodka--I'd rather drink after-shave!
#4
08-06-14, 07:30 PM
Yeah, but.....
Really, I keep reading all these things about the importance of giving it at least a week of curing and not drying out too quickly, so it doesn't spall, and crack, and shrink, and pack up and run off with the circus.
How do I reconcile these points of view?
BridgeMan---what brand?
(Quarter Russian Jew, too).
Really, I keep reading all these things about the importance of giving it at least a week of curing and not drying out too quickly, so it doesn't spall, and crack, and shrink, and pack up and run off with the circus.
How do I reconcile these points of view?
BridgeMan---what brand?
(Quarter Russian Jew, too).
#6
08-06-14, 07:52 PM
Member
I don't like any of the available brands--Smirnoff is the worst. Can't even stand the smell in the room when my sister is drinking it (she's hooked on the stuff).
#10
08-07-14, 07:29 AM
Group Moderator
Unfortunately this forum does not allow you to upload your own avatar. You can only select one from the list.
#11
08-07-14, 09:48 AM
OK, aside from all the yak, thanks for opinion on setting.
What I am trying to get is a way to reconcile in my mind (and in my inexperienced masonry work about to proceed) the wide variance in advice on curing.
In another way of asking the question, why is there such a variance? Something to do with materials or conditions, for instance?
Can you give me more context so I can decide where to place my project in the range?
I'd guess the deterioration of the porch is due to water---it's uncovered---and freeze-thaw.
I do not know when it was built or with how much skill. Certainly permeable surface by now, some of the mortar seams just packed dirt. And seems like a lot of loose dirt, fine gravel, and some #2 gravel within the structure, which seems to have been built with some voids.
It'll get the same weather for now, though I'd like to build a portico sometime.
Thanks again
What I am trying to get is a way to reconcile in my mind (and in my inexperienced masonry work about to proceed) the wide variance in advice on curing.
In another way of asking the question, why is there such a variance? Something to do with materials or conditions, for instance?
Can you give me more context so I can decide where to place my project in the range?
I'd guess the deterioration of the porch is due to water---it's uncovered---and freeze-thaw.
I do not know when it was built or with how much skill. Certainly permeable surface by now, some of the mortar seams just packed dirt. And seems like a lot of loose dirt, fine gravel, and some #2 gravel within the structure, which seems to have been built with some voids.
It'll get the same weather for now, though I'd like to build a portico sometime.
Thanks again
#12
08-07-14, 10:41 AM
Group Moderator
Yes, keeping the mortar wet for as long as possible is best. Portland cement, the magic ingredient in mortar, is generally not considered fully cured for a month (ok, 28 days). The chemical process is driven by water which is why mortar mix will sit for long periods if kept dry. If your mortar dries out too quickly the hardening process will stop.
In the real world you will find that almost nobody does anything special in residential construction. Commercial work like skyscraper foundations or bridges will be kept moist for increased strength but when was the last time you saw a mason doing a house foundation wrap the whole block foundation wall in plastic and let it sit covered for a week or month? Brick and cement block walls are slapped together with almost no concern for the drying rate and it works fine in most situations.
Mortar is porous so it's susceptible to freeze/thaw damage and it's best to minimize the amount under your rock. Some is needed to glue your rocks in place but don't fill large voids with it.
I've also found that many masons cheat their mortar mix. The mortar mix (portland and lime) is expensive and sand is cheap so some will throw in some more sand than recommended to save a buck which can lead to a weaker mortar.
In the real world you will find that almost nobody does anything special in residential construction. Commercial work like skyscraper foundations or bridges will be kept moist for increased strength but when was the last time you saw a mason doing a house foundation wrap the whole block foundation wall in plastic and let it sit covered for a week or month? Brick and cement block walls are slapped together with almost no concern for the drying rate and it works fine in most situations.
Mortar is porous so it's susceptible to freeze/thaw damage and it's best to minimize the amount under your rock. Some is needed to glue your rocks in place but don't fill large voids with it.
I've also found that many masons cheat their mortar mix. The mortar mix (portland and lime) is expensive and sand is cheap so some will throw in some more sand than recommended to save a buck which can lead to a weaker mortar.
