Plaster on foundation that is coming loose

[Maxa]

On one side of the house, the plaster has come off significantly and I'm considering fixing it.
I wonder why the foundation is plastered, does it have any function? That is, more than just looking nice.
I understand that it's because it's ugly that it comes off.

 

[tompax]

On one side of the house, the plaster has come off considerably, and I'm thinking about fixing this.
I wonder why you plaster the foundation, does it serve any function? That is, more than just making it look nice.
I've understood that it is loose because it's ugly.

Depends on what is underneath.

If you have lecablock, you should definitely plaster so that water doesn't just flow in unrestricted.

The plaster also prevents most of the water from penetrating the foundation wall itself.

Of course, leca is water-resistant, so it can be exposed in that way, but it's never good to let water just run right into the house foundation; it's better to plaster so it becomes somewhat sealed.

 

[Maxa]

Nix, no lecablock, old cast concrete!

Depends on what's underneath.

If you have lecablock, you should definitely plaster, so that water doesn't just flow in without limits.

The plaster also prevents most of the water from getting into the foundation wall itself.

Of course, leca can withstand water, so it can be left open in that way, but it's never good to just let water flow directly into the house foundation, so it's better to plaster to make it reasonably tight.

 

[tompax]

Nix, no lecablock, old cast concrete!

Ok. Yes, then the problem is smaller.
However, I would have tried to replaster it, so it holds up a bit better. It always provides a little extra protection.

Replastering a normal plinth on one side of the house, that is, maybe 10 m x 1 m, (10m2), can be done without any problem in a day. You'll need a few bags of plaster, depending on how thickly you apply it.

The advantage is, besides looking better and increasing the value of the house, you get a relatively durable and even surface where not much moss and other dirt can stick, which accelerates decay.

The fact that the plaster has come off at all would probably worry me more. It could mean that it's constantly absorbing moisture, etc.

 

[Maxa]

About 2/3 of the house has a basement and the rest has a crawl space (the latter is in top condition). Should one just dig around the basement part and seal against moisture? Thinking that it's good not to just fix the gable where most of the plaster has come off.

 

[tompax]

Approximately 2/3 of the house has a basement and the rest is crawl space (the latter is in top condition). Should one then only dig around the basement part and seal against moisture? I think it's good not to only fix the gable where most of the render has come off.

If the basement hasn't been drained in a long time, it might be time to do so. Re-rendering, if you do it at all, which is not wrong to do, quite the opposite, only needs to be done on the part that is above ground.

For the part below ground, you'd apply isodrän or equivalent, so it doesn't matter much if the render has come off there. However, if it turns out the joints are very porous, you should re-point those areas and perhaps add a bit of render, a thin layer, just for the durability, before putting up isodrän.