breathable plasters? Izonil, Lime

[jungle_jim01]

So further to my previous post about dealing with a damp area, you'll be pleased to know i'm not going to use tanking. Later on i'll put a French drain in i think but on the internal side i'm planning on using a breathable plaster. Obviously there's the traditional lime option but i'm also wondering about modern alternatives. I've heard limelite mentioned but i'm not sure about it's breathability or suitability in this situation (penetrating damp from higher external ground level).

I've also come across "Izonil Waterproof & Breathable" plaster: http://www.izonil.com
The person i spoke to on the phone said it would be ideal in this situation (but he would of course!). I'm wondering if anyone's used it and also what the advantages/disadvantages are over traditional lime plaster.

Also...on a slight tangent: My plasterer hasn't worked with lime in the past but he is a good plasterer so any tips if he agrees to use lime?

Thanks for all the advice as always

 

[TheForge]

Limelite is cementitious and Izonil sounds strange to me.

If you want the wall to 'breath' and allow moisture to transport through the coating and have the opportunity to evaporate then what's wrong with lime plaster?!

I can't quite understand how a plaster can be waterproof (and therefore trap moisture in the wall) yet also be breathable? I understand that air may pass through it but if this allows transportation of moisture then it is, by definition, not waterproof?!

Keep it simple and use the tried and tested method would be my suggestion!

The only real solution is to lower the outside ground level and or put in some form of drain. We've done exactly that front and back and it's worked well along with removing cement 'tanking' plaster from the inside.

 

[MdB]

I would place a note of caution on using lime. Lime is good at letting moisture evaporate, but it doesn't work miracles. If you have penetrating damp, a lime finish will still be damp if the moisture levels are high enough. In this case a tanking system of some sort, fitted properly, would be required to remove the damp issues though this will of course mean that the inside of your wall will have far higher moisture levels.

If you can do something about the reason for the penetrating damp then I would do all I could first.

 

[jungle_jim01]

Thanks for the replies...yeah i know i need to sort out the cause of the damp. and plan on putting a French drain in. I's just not feasible for me at the moment, but is a priority for the next year or so. I had been wondering how well lime would hold up in a damp area.

As far as Izonil goes, as i understand it, it's similar to a breathable jacket in that it won't let liquid water absorb through it's structure but is permeable to vapour, thus avoiding dampness within the plaster.

 

[Lime]

As far as Izonil goes, as i understand it, it's similar to a breathable jacket in that it won't let liquid water absorb through it's structure but is permeable to vapour, thus avoiding dampness within the plaster.

So it isn't "breathable" as this forum uses the word, it is waterproof.
Tanking by any other name except air can pass through it. (!)
Its a quick and modern fix doing nothing to restore the building back to how it should work.
As has been said the cause of the problem needs to be sorted out, everything else is a short term solution.

 

[Lime]

Also...on a slight tangent: My plasterer hasn't worked with lime in the past but he is a good plasterer so any tips if he agrees to use lime?

Lime is very different to modern plaster.
My tip to your plaster? He needs to practice or attend a course in lime plastering.

 

[jungle_jim01]

Thanks again for the advice...just in case anyone's interested, i'm trawlling the net trying to find more information about izonil and found this: http://online.eastherts.gov.uk/rkyvportal/showimage.asp?j=3/10/2065/LB&index=221346 page 6 is interesting. I suspect there may be few gasps ;-)

 

[TheForge]

This application is for a basement, i.e where it is not possible to prevent damp penetrating and as such this solution is a pragmatic compromise, not necessarily the best solution to preserve the fabric, but a means to create a 'dry' wall surface. In an above ground situation there are better option, primarily dealing with the source of the moisture.

I'm still very cynical of the breath ability of the Izonil plaster in the sense we normally think of it.

 

[Zebra]

i know i need to sort out the cause of the damp. and plan on putting a French drain in. I's just not feasible for me at the moment, but is a priority for the next year or so. I had been wondering how well lime would hold up in a damp area.

If you apply a lime plaster before sorting out the cause of the damp, and then sort out the cause of the damp a year later, my limited experience would suggest that the lime plaster would not suffer, it would not fall off, in fact if lime plaster stays moist for longer that may help it to carbonate better. The wall would just be damp until such time as you sort out the other things. If you keep furniture away from the walls and allow the dampness that is coming in to evaporate, that will help to prevent mould. Then when you sort out the cause of the damp the lime will dry, and will be no worse off than if you had done it in the reverse order.

 

[rebeccac]

We buy a ready mixed lime plaster in Italy -Biocalce and as we were falling so behind we got a local plasterer in to do some plastering with it.He was very nervous but in 2 hours he did what takes us 2 days! He didnt really pay enough attention to keeping the previous layer damp so we did get a small area of craking but overall we were impressed.

However mixing and applying a lime plaster from scratch is definetly one for a professional lime plasterer (or householder with lots of experience)

www.myabruzzohome.blogspot.com