plaster repairs

[charlie-ia]

im a bit suprised at the amount of posts on various aspects of repairing plaster. i think im missing something. i understand you would do it if it was special, but everyone seems to be at it! should i be doing it too?

when would you do a repair, and when would you patch it up with fresh plaster? or when would you replaster the whole wall?
is it just cheaper and easier to repair? i dont expect it is, not when i read about grouting the plaster, or putting back up plaster thats already fallen off. is it mostly about preserving the historic fabric?

i must admit i never thought about repair, my plan was to sweep up what fell off, remove anything that was on the verge of falling off, and hope my lime would hold up the rest as i filled up the gaps.seemed ok on the small bits ive done so far.now that seems very simplistic and i wonder if i should be trying to save more than i have

wouldn't drilling through the loose plaster into the stone beneath cause more damage? your house would end up looking like a pegboard surely? and wouldnt glueing fiberglass stop the wall breathing?

sorry theres so many questions, i find the more i find out the more i need to know! :?

 

[Ian Bond]

Grouting and specialist conservation techniques are expensive, and usually reserved for important decorative historic plaster work.

The thing is, people often hack off a lot more plain plaster than necessary, because it sounds a bit hollow. History in the skip.

As long as the hollow bits are isolated areas and not the whole wall, you can usually save it.

Removing all of the plaster would create tons of waste and mess, so saving as much as possible (as you are doing) is quite right.

We use the screws and washer to secure lath and plaster. On solid backgrounds if you patch carefully it will help secure the surrounding plaster.

Where a room has loads of missing plaster patches, repairing it is very time consuming and hard work. But at least you've got the existing plaster as a guide to work to, so you can match the finish. Well try to.

The more plastering I do, the more I appreciate how hard it is, and the more of the original stuff I want to save.

Hope that's answered your question!!

 

[inwood]

I agree, I've been trying to save as much of the original as possible. Partly because it shows the history of the house. The kitchen/pantry were all cement and gypsum (now lime), the dining room was daub scratch coat, lime top coat with very fine hair (possibly goat) in the top coat. All downstairs plaster was three coat work. All upstairs work is coat and a half (probably because it was cheaper). It's definitely possible by looking at the plaster to see the different stages of the houses development, something that would be lost if it was wholly replastered.

Conservation of plaster would appear to be best practice throughout history from what I can tell - there is evidence throughout the house of plaster being repaired rather than replaced wholescale.

I think the rip it out and replace it mentality is a more modern one.

It would have been easy to remove all the existing plaster and put stud wall/plasterboard up but I'd lose all the character in the walls and besides it's listed so I can't (not that I'd want to).

Unfortunately upstairs all the original plaster was skim coated with gypsum and then emulsion painted. As a result the original top coat is in a poor condition so will need to be re-skimmed with lime once it's been repaired but the base coats and what remains of the top coat (particularly the lovely old colours from years of limewash) will remain for future generations to marvel at how long it's survived.

Another valid reason is cost. If I remove all the plaster and replaster with three coats it will cost me too much.

I think it also depends on the house. I think some might find it odd to repair plaster in a 1980's semi but it's probably only a matter of time. 1930's, 1940's properties, particularly those of some importance are now being treated with care and love.

 

[Cloudscape]

I'm sure this has been asked before, but is there any way to re-use old lime plaster? (And lime mortar, I suppose). If I really had to replace any plaster, I'd feel bad throwing it away. Sometimes it crumbles and releases the aggregate and other additives. Can any of it be re-used, even for small repairs?

 

[Ian Bond]

Yes, I've done it. But it does make a physically hard job even harder!

Crush up the old plaster, and add new lime and hair. Good as new.

Re-using it is entirely the right thing to do.

I can't chuck stuff away anymore - my council just won't accept rubbish at the tip - everything has to be recyclable. But you can pay (a lot) to dump stuff. Not an attractive option.

 

[Ian Bond]

wouldnt glueing fiberglass stop the wall breathing?

Not sure about that one - I do use small amounts of fibreglass mesh to reinforce joints and thin patches over washers or cable conduit etc. It's an open mesh and won't affect breathability. No glue is used.

 

[charlie-ia]

thanks, thats great, and very reassuring. it was really bugging me.