Interior lime: #1 - what to do with gypsum skim?

[BillyRay]

Hello smart diynot folks,

I live in a house which is lime plastered inside - old single skin georgian.

To "smarten" it up to sell (also read: hack job to cover up any issues), the previous owner had some monkey skim over the lime plaster with gypsum.

This, if I understand correctly, is why these skimmed areas are now exhibiting cracks (lime plaster underneath is happy to expand/contract - gypsum not so much).

Any recommendations on what I should do with this situation? It seems like two real options:

1. Leave it as it is and live with the cracks.
2. Strip off the gypsum and refinish the lime.

Any additional thoughts?

Cheers,
Will.

 

[peaps]

personally I would strip the lot off and start again. The walls need to breath and gypsum skim will sop this and add to damp problems. You don't have to see damp for there to be high damp content in the wall...

 

[Possel]

I'm with peaps on this. Rather than worry about just the cracks, you need to understand more about how an old house is meant to work - it's very different to a modern house. Google for "period property lime mortar" and have a good look at the sites you find. Basically if you retain the gypsum you might well find all sorts of other problems with dampness in due course.

You could also look at the entries for "dampness" and similar keywords on my blog at http://houseintheenchantedforest.blogspot.com/

As peaps asks elsewhere, is your house listed?

 

[dougalhouse]

If the walls were cavity walls and there is no history of damp, is it still not okay to use gypsum products?

Sorry to hijack this post!

 

[peaps]

If the walls were cavity walls and there is no history of damp, is it still not okay to use gypsum products?

Sorry to hijack this post!

Depends but usually no. It may be that it has no history of damp because it was done in lime, add gypsum skim and you may find that the once free from damp wall will start to show signs.

 

[BillyRay]

Thanks all.

Sounds sensible.

When you say "strip off the lot" I presume you mean back-to-brick or possibly back-to-decent layer before building up the lime renders again?

Will

 

[peaps]

Thanks all.

Sounds sensible.

When you say "strip off the lot" I presume you mean back-to-brick or possibly back-to-decent layer before building up the lime renders again?

Will

Yes mate, back to brick.

 

[odilon]

Thanks all.

Sounds sensible.

When you say "strip off the lot" I presume you mean back-to-brick or possibly back-to-decent layer before building up the lime renders again?

Will

Yes mate, back to brick.

Sorry, but I have a similar problem and wonder if I can ask some advice from some of the Lime Plaster experts on this forum.

We recently did a major rehab or our 1890's house, including removing some horrible cement render and replacing a surface layer of sand-cement based mortar with lime (the original was lime). Inside, wallpaper was removed and a new skim of plaster added in most rooms. I now realize that the original plaster was lime, and the new skim coat gypsum, something I didn't understand at all. A few of the walls are now having some stubborn damp problems, and I fear the combination of lime mortar outside and non-lime plaster inside is causing problems.

Can anyone advise on what might be happening, and what we can do to address it?

Thanks!