Should you water a newly plastered wall the same day you applied the plaster? It has been sunny and 20 degrees during the day. It's an outdoor leca wall. Or should I water it tomorrow morning?
 
It is rendering mortar c from Byggmax if that matters.

Talked to the craftsman now (from a completely different culture) and he says "no water! concrete water yes, puts no water!"
 
A
I would follow the manufacturer's own instructions rather than listen to such a rough generalization. Read the packaging and the manufacturer's product sheet. The craftsman might want to speed up the work by letting the plaster dry way too quickly to be able to paint?
 
No, I will paint myself at a later date.

The thing is, I have already pointed out a few things during the construction, so the relationship is a bit frosty.

The alternative is that I secretly water when he has gone home for the day (he's coming back tomorrow to do some carpentry)

If there are dry cracks, when do they appear? And how do you fix them?
 
It's difficult to communicate, then.
 
A
If the sun is shining and it's 20 degrees, I would definitely have been generous with post-watering. It would certainly be interesting to try to get the craftsman to justify why he recommends not following the manufacturer's instructions. If you overdo the post-watering, the mortar may weaken, but I would think it's more likely to get a poor result if you don't water.

Any drying cracks are only of aesthetic significance (aside from any potential consequences if moisture may make its way in the future). Depending on the type of paint, painting can completely fix/conceal the drying cracks, as they are usually so fine and numerous that they are difficult to repair with mortar without having to fine plaster the entire wall.
 
Aha. Thank you for the response.

When can one go for the first round and water? How many hours should pass?
 
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Per-Johan
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M
When watering does not affect the plaster, such as washing away material or leaving marks, it is fine to water. A few hours after the plaster is finished processing, depending on several factors. If it begins to whiten, watering should commence. Ideally, the plaster should be kept at least moist for the next few days after plastering. The day after and during the next 3-4 days, you can thoroughly soak the wall with water as soon as it becomes dry.

If the sun is shining directly on the wall during plastering, the wall should be covered/protected from direct sunlight, otherwise, drying cracks will definitely occur.
 
I would not recommend watering the plaster. It is such a thin layer that needs to dry, and the risk is that the underlying stone absorbs the water. We build many plastered houses, and you want it to dry as quickly as possible.
Concrete, on the other hand, is watered because the surface dries first due to the thickness of the construction.
 
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Joak
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M
Strange advice. Watering cannot lead to any negative side effects as what is absorbed into the lecan slowly migrates out. However, you risk reduced strength and drying cracks if you don't water.

If you want it to dry as quickly as possible, it probably has to do with working on a contract basis and not because the result will be better then.
 
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Gabsson
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Matti_75 Matti_75 said:
I would not recommend watering the plaster. It's such a thin layer that needs to dry, and there's a risk that the underlying stone absorbs the water. We build many plastered houses and want them to dry as quickly as possible.
Concrete, on the other hand, is watered because the surface dries first due to the thickness of the construction.
The plaster shouldn't dry, the plaster should cure.
This happens when there's moisture and carbon dioxide.
If you remove moisture, the process stops.
So the follow-up question is, when is this process complete?
 
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