Old cottage interior

[chinablue777]

A friend of mine has just asked me to give him a hand to decorate a single room in a 17th century cottage. The problem is two of the walls are cob. He wants to get rid of the old plaster back down to the cob , and then re-do , but the problem is what to re-do with!. I have worked on cob a few times before but only on the outside. I don't have a clue what would be best to use indoors. Any ideas anyone?

 

[TheDec]

Cob is an earthen plaster, and the mention of it takes me back a very very long way back to what was then a very involved c&g. If memory serves me correct cob should be painted only with a breathable paint system.

Dec

 

[JohnD]

Basically a mud hut. I believe it usually has a limewash coating. If you try and take the plaster off, where will you stop? (should be lime plaster)

 

[chinablue777]

Thank you Dec and John. Dec , you say it should be painted with a breathable paint system , but not directly onto the cob surely? You have obviously worked with cob yourself many years ago, (your words not mine !! ) so you will know that cob will literaly suck the paint right off the brush!. So I am assuming that plastering first is the way to go?. Would that be your everyday kind of plaster?
John you are right in saying it is basicaly a mud hut!. A very old mud hut , but a mud hut all the same. The old plaster has to come off that is for sure , and taken off down to the cob itself to ensure a proper job. Where will it stop you ask , good question , but cob as you know , was always layed down thick!. These walls are at least 3 feet thick so I am hoping it will be a painless operation!. I just need to know if everyday plaster will do , or will it have to be a bit special. Thank you to both of you , and I look forward to your replies.

 

[misterhelpful]

I've never dealt with it myself but I do know, as JohnD says, that the cob blocks would originally have been covered with a lime plaster. This could have been haired or unhaired and even made with cow manure. This would allow the cob to breathe and would have been painted with a limewash.
For the best advice on what to use it would be a good idea to ask in the Plastering forum where I'm sure a lot of the guys will be able to help.

 

[peaps]

Thank you Dec and John. Dec , you say it should be painted with a breathable paint system , but not directly onto the cob surely? You have obviously worked with cob yourself many years ago, (your words not mine !! ) so you will know that cob will literaly suck the paint right off the brush!. So I am assuming that plastering first is the way to go?. Would that be your everyday kind of plaster?
John you are right in saying it is basicaly a mud hut!. A very old mud hut , but a mud hut all the same. The old plaster has to come off that is for sure , and taken off down to the cob itself to ensure a proper job. Where will it stop you ask , good question , but cob as you know , was always layed down thick!. These walls are at least 3 feet thick so I am hoping it will be a painless operation!. I just need to know if everyday plaster will do , or will it have to be a bit special. Thank you to both of you , and I look forward to your replies.

English heritage will put you on the right track and don't forget list building permissions