I have just sanded off plastic paint from the inside of the basement (recreation room) in my house from 1961.
Now I want to fix it so that the walls become straight again, as they were before sanding, and then paint.
It turns out that the remaining plaster is very sandy, so I probably need to prime first before I can plaster.
I went to the building store and they said that each plaster has its own primer, so I need to decide which plaster to use before buying the primer.
I am fairly convinced that the substrate today is some type of kalkputs (lime plaster) since it is so sandy. I'm unsure if it is just lime or exactly what it is. Behind the plaster, there seems to be some form of insulation - see pictures HERE
The room is 6.7 x 4 meters.
Based on the pictures, I wonder:
1. What type of plaster should I use? KC-bruk?
2. What should I prime with before plastering?
3. Can anyone confirm that it is kalkputs that is there today?
4. Do you plaster directly on, or is reinforcement mesh or something similar needed?
5. What would you say is an estimated labor cost if someone else is to do the plastering? I will prime and paint myself.
Thanks in advance 🙂
Now I want to fix it so that the walls become straight again, as they were before sanding, and then paint.
It turns out that the remaining plaster is very sandy, so I probably need to prime first before I can plaster.
I went to the building store and they said that each plaster has its own primer, so I need to decide which plaster to use before buying the primer.
I am fairly convinced that the substrate today is some type of kalkputs (lime plaster) since it is so sandy. I'm unsure if it is just lime or exactly what it is. Behind the plaster, there seems to be some form of insulation - see pictures HERE
The room is 6.7 x 4 meters.
Based on the pictures, I wonder:
1. What type of plaster should I use? KC-bruk?
2. What should I prime with before plastering?
3. Can anyone confirm that it is kalkputs that is there today?
4. Do you plaster directly on, or is reinforcement mesh or something similar needed?
5. What would you say is an estimated labor cost if someone else is to do the plastering? I will prime and paint myself.
Thanks in advance 🙂
It is lime plaster. Water first. If it absorbs poorly, you can use primer mixed with sand, like gypsum. Otherwise, after watering, you can coat the surface. Use hydraulic lime mortar. You have organic materials in the walls, so use a method that can transport water. Avoid using kc-mortar, as you would have to knock everything down. You want the softest surface on the outermost layer to allow the material to absorb any movements in the house. If you plan to paint afterward, use breathable paints like kc-paint or lime paint. Consider the water evaporation. Try to have good ventilation, while also watering the plaster at least once every day for the next 3 days. Make sure it has settled before watering.
Thank you for your response!
I've googled a bit more now and came across the term air-hardening lime mortar. This is supposed to be even softer than the hydraulic one, maybe it's better in my case to use the air-hardening one? How do you know that?
I will try watering instead of primer, but do I understand you correctly that if I prime, I'm safe and don't need to water before plastering? So watering is just a cheaper alternative?
Slamma or plaster? I guess I need to google the difference
What does it mean that I should consider the water release?
Can I paint with silicate paint or is lime paint what works?
Apologies for my annoying questions, appreciate your help
I've googled a bit more now and came across the term air-hardening lime mortar. This is supposed to be even softer than the hydraulic one, maybe it's better in my case to use the air-hardening one? How do you know that?
I will try watering instead of primer, but do I understand you correctly that if I prime, I'm safe and don't need to water before plastering? So watering is just a cheaper alternative?
Slamma or plaster? I guess I need to google the difference
What does it mean that I should consider the water release?
Can I paint with silicate paint or is lime paint what works?
Apologies for my annoying questions, appreciate your help
It's a basement, and considering the choice of materials for the walls, you should focus more on moisture transportation capability. In that regard, hydraulic lime mortar is the best.
No, primer is meant to increase absorbency. Old plaster or especially concrete loses this ability over time. Lime that hasn't been exposed to a dry climate is usually reasonably absorbent anyway. You water it to check how well the material absorbs. If the wall is still wet after 30 minutes without external factors like high heat or sun, then you don't need to prime.
You should always water before plastering, regardless of whether the material is dry.
Plastering involves mixing to a slightly looser consistency than regular plaster and brushing it on with a slurry brush. This helps the plaster adhere better afterward.
Once the plaster has set, you must water it to prevent cracking. If you're in a space without ventilation, there's a risk the air will become saturated with moisture. The moisture needs to go somewhere, so it forms a film beneath the plaster you applied, and all or parts of the plaster can detach from the substrate. This is what I mean by high moisture loss.
If you're missing or have poor ventilation, you should expect at least a day per cm layer of plaster.
No, primer is meant to increase absorbency. Old plaster or especially concrete loses this ability over time. Lime that hasn't been exposed to a dry climate is usually reasonably absorbent anyway. You water it to check how well the material absorbs. If the wall is still wet after 30 minutes without external factors like high heat or sun, then you don't need to prime.
You should always water before plastering, regardless of whether the material is dry.
Plastering involves mixing to a slightly looser consistency than regular plaster and brushing it on with a slurry brush. This helps the plaster adhere better afterward.
Once the plaster has set, you must water it to prevent cracking. If you're in a space without ventilation, there's a risk the air will become saturated with moisture. The moisture needs to go somewhere, so it forms a film beneath the plaster you applied, and all or parts of the plaster can detach from the substrate. This is what I mean by high moisture loss.
If you're missing or have poor ventilation, you should expect at least a day per cm layer of plaster.
Thank you for your answers, they have really helped a lot! So it's grounding first, then plastering with hydraulic lime mortar, and then painting with lime paint!
Am I right in thinking that grounding is a step one can do oneself, and then bring someone in for the plastering? I can also do the painting myself. Or is plastering with hydraulic lime mortar so easy that one should also do it oneself? I want to achieve smooth walls, even though it's in a basement
Am I right in thinking that grounding is a step one can do oneself, and then bring someone in for the plastering? I can also do the painting myself. Or is plastering with hydraulic lime mortar so easy that one should also do it oneself? I want to achieve smooth walls, even though it's in a basement
It depends a bit on how handy you are. It's not hard if you have the willingness to learn. There has to be a first time at some point.R ravve007 said:Thank you for your responses, they've really made things easier! So it's a matter of grounding, then smoothing with hydraulic lime mortar, and then painting with lime paint!
Am I right in thinking that grounding is a step one can do oneself and then hire someone for the plastering itself? I can also do the painting myself.
Or is plastering with the hydraulic lime mortar easy enough that one should do this as well? I want to achieve smooth walls, even though it's in a basement
If you want completely smooth walls that are straight, you need to set up material that you level the entire way. The simplest way to achieve this is to set up material that you can scrape against, like battens or something similar in each corner about four to five cm in with the help of a level tool. Stretch a mason line between these two at the bottom and top that you can align and set up the other battens against.
Then you water to see if the material absorbs enough. If it's still wet an hour later, you need to apply primer.
First, apply a slurry. Then apply a layer no thicker than 1.5 cm. 3 cm if you've netted. Allow it to set for a day before you apply the final layer. You have to pull it with a long trowel to compact the plaster. For the final layer, apply the plaster with a long trowel. Then, use a straightedge to scrape off excess plaster along the guide rails/ribs you set up. For a smooth surface, rub the plaster after it has set somewhat. Let the plaster set. Water it. Then, at the earliest after a day, remove the battens/ribs. Here, you need to be careful. Take a knife or a putty knife and run it along the battens/ribs as these absorb moisture before you remove them.
Then you can plaster over the holes that form from each batten/rib. Water every day for three days thereafter.
You can check out this
However, it's a cement-based mortar, but the principle is roughly the same.
@Silver78 I am enormously impressed by your answers! Thank you so much again and again!!
I feel very excited now, but I will probably try to hire someone for the plastering since I don't have the time. I'm just worried that it's a task that requires a lot of waiting time (drying time, etc.) and therefore the labor cost might be high, but I'll take it.
One last question, what should you fill the larger holes with? Plastering 1.5cm at a time is probably OK, but I don't think that applies to the deep holes, here I feel like there must be a way to "throw in" significantly more than 1.5cm at a time?
I feel very excited now, but I will probably try to hire someone for the plastering since I don't have the time. I'm just worried that it's a task that requires a lot of waiting time (drying time, etc.) and therefore the labor cost might be high, but I'll take it.
One last question, what should you fill the larger holes with? Plastering 1.5cm at a time is probably OK, but I don't think that applies to the deep holes, here I feel like there must be a way to "throw in" significantly more than 1.5cm at a time?
@ravve007
This is the forum this is intended for. Next time it's me who learns something. The holes that are there can you fill with more, but then some type of mold is required so that the plaster does not detach from the substrate. This mold can be a piece of OSB board or similar and simply plug it into the wall. Alternatively, something in tension so that the plaster stays in place.
This is the forum this is intended for. Next time it's me who learns something. The holes that are there can you fill with more, but then some type of mold is required so that the plaster does not detach from the substrate. This mold can be a piece of OSB board or similar and simply plug it into the wall. Alternatively, something in tension so that the plaster stays in place.
I've received some quotes for the plastering work. I got the best gut feeling from one company, although they want to reinforce the wall with a reinforcement mesh and then use a fiber-reinforced plaster mortar, i.e., not lime mortar.
Does anyone know more about this? Is it an equally good method (maybe better?) than using hydraulic lime mortar? According to the company, the fiber-reinforced plaster breathes, but I'm not sure. I'm worried that it won't hold up or something similar.
The company provided a quote based on a picture/description and hasn't been on site.
The quote states that the following is included:
• PRIMING OF SURFACES.
• PLASTERING WITH FIBER-REINFORCED PLASTER MORTAR.
• REINFORCEMENT WITH REINFORCEMENT MESH.
• FLOATING OR BROOMING OF WALL SURFACE.
Help!
Does anyone know more about this? Is it an equally good method (maybe better?) than using hydraulic lime mortar? According to the company, the fiber-reinforced plaster breathes, but I'm not sure. I'm worried that it won't hold up or something similar.
The company provided a quote based on a picture/description and hasn't been on site.
The quote states that the following is included:
• PRIMING OF SURFACES.
• PLASTERING WITH FIBER-REINFORCED PLASTER MORTAR.
• REINFORCEMENT WITH REINFORCEMENT MESH.
• FLOATING OR BROOMING OF WALL SURFACE.
Help!
With a reinforcement fabric at the bottom, the plaster itself becomes less sensitive to movements. However, I'm not sure about the hygroscopic difference (i.e., the ability to transport moisture) between this fiber plaster and hydraulic lime mortar. But fiber plaster contains cement and becomes harder, which logically suggests to me a worse ability to transport water. The diffusion-open property varies from material to material. Given that it's a basement, I wouldn't risk trying anything different from the solution you currently have. The downside is that hydraulic lime is a soft material, making the plaster porous. If you paint with something harder than the substrate, you'll get cracks in the paint. I don't think you'll become any wiser from this post.
@Silver78 really, thank you for your input! That Hey'di seems like an uncertain choice, but I'm just going with my gut feeling... hydraulic lime mortar and a lime paint are probably the safest/most common option I feel as well, so maybe I should stick to that. Price-wise it's comparable to Hey'di.