Plaster leca before winter?

[sollentuna]

I have no idea if this thread is in the right topic category, but I'll try anyway!

We are building a hillside house and on the lower floor, it is built with leca. The part that is above ground is not plastered at all and is completely untouched. Now I'm wondering what is required before winter comes. Can you leave it as it is, is it enough to coat it, or do you have to finish it with proper plastering?

Time has never gone by so fast as this year. We have a lot of things we need to get done before winter!

 

[Magnus_Nordmark]

Hi!

No, you don't have to plaster the wall before winter. However, keep in mind to cover it so that it doesn't get rained on too much because LECA absorbs and transfers moisture. A moisture-filled wall and freezing temperatures are not a good combination...

 

[sollentuna]

But is it really possible to avoid a wall getting wet when it is 2.50 m high and has another floor on top of it, and only after that comes the roof?

 

[Immobil]

But is it really possible to avoid a wall getting wet when it is 2.50 m high and then has an upper floor on it and only after that comes the roof?

Can't you cover it with a tarp? ???

 

[Birgir]

Cover it with plastic or cheap light tarp, it is easy to tie
Regards

 

[Magnus_Nordmark]

But is it really possible to prevent a wall from getting wet when it is 2.50 m high and has then a second floor on it and only after that comes the roof?

It's not easy, but you need to cover it with a tarp or something similar... It involves some covering work, so the question is if it's not better to plaster it before winter anyway...

 

[sollentuna]

It seems like it might be better to plaster it anyway, it's not that much so it will probably go pretty fast.

The part that is below ground we have coated with a thin slurry applied with a brush, is that enough or does it need to be thicker? I was planning to hire someone for the plastering later since I've got the idea that it's hard for an amateur to make it look good, but I'd like to wait until next year.

So the question now is if the coating is enough and if one should mix in any moisture barrier into the slurry?

I might be completely off track, I gratefully welcome tips!

 

[Magnus_Nordmark]

It sounds like it's better to plaster it anyway, it's not that much so it should go pretty fast.

The part that is below ground level we have covered with a slurry, i.e., smeared on a thin mortar with a brush, is that enough or does it need to be thicker? I have thought about hiring someone to do the plastering later because I've got the idea that it's hard to make it look good as an amateur, but I would like to wait until next year.

So the question now is if the slurry is enough and if you should mix in any moisture barrier in the mixture?

I might be completely off track, I would appreciate any tips!

You should definitely have a moisture barrier in the plaster that is below ground level. You should have 1 cm thick plaster, on top of what you've slurried already... Don't forget the Platon mat on top of the plaster afterward...

Whether you should do the job yourself depends a bit on what you're after. Do you want smooth plastering? Or would you rather have a brushed surface? A smooth plaster isn't easy to make look good as an amateur, or as a "first-time plasterer." A brushed surface is considerably easier, and you can probably manage to do it yourself.

On the masonry foundations I've been involved in building, we've let the customer choose between a brushed and smooth plastered surface by showing a sample area. Most choose brushed, which gives a bit more character to the foundation.

When brushing, it's enough to throw on the plaster with a trowel evenly over the surface. Then take a wall brush, wet it, and drag it on the plaster in the pattern you want. The simplest pattern is to pull vertically from bottom to top. But you can, of course, create the pattern you like.

You can get help with how to mix the mortar at the building supply store.

If you want more detailed tips and assistance just give a shout!

Good luck!

 

[sollentuna]

Lovely quick response!

What is below ground has been coated with a moisture barrier, and then we added Pordrän on top of that. (Please don’t say it’s wrong, because we've already filled it back in ;-).)

But what about what will be above ground? Do I need to both coat and plaster to make it waterproof, or can I coat it this year and plaster in the spring? Should there be a moisture barrier in the coating there as well?

I think I want a smooth plaster finish; it’s not a plastered house but a wooden house with a basement, so a brushed surface feels a bit "rough." But I don't really know what they look like, so I shouldn't say too much!

 

[Magnus_Nordmark]

Wonderful quick response!

What we have underground is sealed with a moisture barrier and then covered with pordrän. (Please don't say that's wrong, because we've already covered it ;-).)

But what about what will be above ground? Do I need to both seal and render to make it watertight or can I seal this year and render in the spring? Should there be a moisture barrier in the sealant there as well?

I think I'd like smooth rendering, it's not a rendered house but a wooden house with a basement floor underneath, so a brushed surface feels a bit "rough." But I don't really know what they look like so I shouldn't say too much!

What's above ground doesn't need sealing, and you also don't need a moisture barrier in the render. It's fine to render directly onto the wall.

Whether it's too rough or not is a matter of taste. I think it looks better with a brushed surface; it adds a lot more "life" to the surface that way... Moreover, it's simpler, cheaper, and faster to do...

My tip would be to look around at houses with rendered walls to see how the different options look.

I would undoubtedly choose the brushed surface.

 

[sollentuna]

I have looked at the Opticot website about how to apply render. I think what I imagined with roughcast is what is called scratch coat, i.e., render with "lumps" in it, but maybe that's not what is meant.

So, I don't want render with "lumps," but it's okay if the surface is a bit rough. Is there a picture of a brushed wall?

On the other hand, if I render myself this year and it turns out super ugly, do I have to knock everything down and start over in the spring (with the help of a professional), or is it enough for a professional to apply a thin layer on top of my ugly render (if it turns out ugly)?

 

[Magnus_Nordmark]

I have now looked at the optics website on how to plaster. I think what I had in mind with coarse plaster is what they call "spritputs," i.e., plaster with "bumps" in it, but maybe that's not what it means.

So, I don't want plaster with "bumps," but the surface can be somewhat rough, that's fine. Is there a picture of a brushed wall?

On the other hand, if I do the plastering myself this year and it turns out super ugly, do I have to knock everything down and start over in the spring (with the help of a professional), or is it enough for a professional to apply a thin layer over my ugly plaster (if it turns out ugly)?

I understand now. What I mean is plaster without bumps, just a bit rough. I've searched but haven't found any good pictures... but if I come across something, I'll catch it...

Plastering as I described is actually not that difficult. My tip is to try it on a small area in a place that's not very visible. If it looks too bad, scrape it into the bucket and try again!

Throw on the plaster, distribute it somewhat evenly and then brush it from bottom to top.

What do you think, are you willing to give it a try? ;-)

 

[sollentuna]

I looked at your pictures jureit and it looked great, but I'm still a bit hesitant about whether it will look good if we do it. The plaster itself will be at the entrance so it will really stand out if it doesn't turn out well.

There is a house nearby that had unplastered leca last winter (and it is still unplastered) so maybe we should take a chance and leave it.

But if we were to try to do it ourselves, do we have to do everything in one day or can we stop "midway" to continue later? If I understood jureit's pictures correctly, you've applied the plaster in two layers, but on Optiroc's website, it seems like they say you should apply everything at once. That way, I suspect everything should be finished before it dries whereas it would feel better to apply in two layers. Then you do the base layer over a few days and then you can apply an outer layer in one day.

 

[Magnus_Nordmark]

I looked at your pictures jureit and they looked really good, but I am still a bit hesitant if it will look good if we do it. The rendering itself should be at the entrance, so it will really be visible if it doesn't turn out well.

There is a house nearby that had unrendered leca last winter (and it is still unrendered), so maybe one should take a chance and leave it.

But if one were to attempt to do it themselves, do you have to do everything in one day or can you stop "in the middle" to continue later? If I understood jureit's pictures correctly, you've applied the render in two layers, but on optiroc's website, it seems they say you should apply everything at once. In that way, I suspect that everything should be completed before it dries while it would feel better to apply it in two layers. Then you do the base layer over a few days and then you can apply a top layer in one day.

Wait if you think that seems better....

You apply the render in one go, like, in one layer at a time. You should do a whole wall without seams, otherwise, it can show where you have joined somewhere. However, it's perfectly fine to make seams in corners or at some opening.

 

[Magnus_Nordmark]

We applied 2 layers because we wanted to build up some structure = wanted a certain thickness and then it's easier to apply it 2 times when you're a beginner klutz.

Also, I'm not sure, but doesn't it require a certain thickness so the joints between the lecan don't "show through"?

I think I see walls everywhere where you can see how the blocks are behind the plaster, and I think it looks so dreadful.

Just like Mange says, you can't join the last layer in the middle of a wall or something like that.

Well, the block joints can show through if the plaster isn't painted and is also damp. A plastered surface should absolutely be painted! If the plaster stays unpainted, then wind and water will erode the plaster because it is so porous.

Now, one shouldn't paint the plaster right away, but if you're plastering now, paint towards the summer of 2005...

Then, regarding the thickness, 1cm is enough from a strength and construction point of view. In most cases, about 1cm is enough if you want to make some patterns too...