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when is hair in lime plaster/render necessary?
- Thread starter robgil
- Start date
Gervase
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- 1,500
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- North London
On any surface liable to movement, however slight - laths, rubble-stone (particularly if you've been putting new door openings and windows through a wall or have chipped off cement render), reed mat, strawboard...
To be honest I use hair in all plaster and render in the scratch and float coats. It's not expensive and it does give peace of mind.
To be honest I use hair in all plaster and render in the scratch and float coats. It's not expensive and it does give peace of mind.
I do as well Gervase , would there be any reason why a hired plasterer wouldn't use it or would he/she use a substitute? A friend of mine has had some external rendering done and asked for lime however no hair was used and its all cracked to buggery , its a timber framed house with lath to fix the render to. I would have thought it pretty obvious that a binder of some sort would have to be used under these circumstances.
Gervase
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Well, it is a pain in the bum to stand over the mixer teasing the stuff in, so I can understand why some people won't do it. But lime on lath over a timber frame, without hair - hey presto, you've just described it.
Someone needs to say some sharp words, and someone needs to listen. Has the bill been settled yet?
Someone needs to say some sharp words, and someone needs to listen. Has the bill been settled yet?
rebeccac
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on the other hand we have used some 'biocalce'(NHL 3.5,sand,marble dust and pozzolan ) mortar on rubble walls with no cracking -however what happens during the next earthquake is anyones business!
www.myabruzzohome.com
www.myabruzzohome.com
Penners
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- Suffolk, England
I think you may have omitted the word "yet", Rebecca. :wink:rebeccac said:on the other hand we have used some 'biocalce'(NHL 3.5,sand,marble dust and pozzolan ) mortar on rubble walls with no cracking
A rubble wall may not be 100% stable in the long term, but it's a lot more motionless than a timber-frame structure, which is moving all the time.
the bill has been settled , its a pretty good job except for one gable end, its west facing and gets a lot of sun so it may have dried out too quick. they came back and filled the cracks with what looks like lime putty, didnt sand it then lime washed over it , when it rains its quite visible. its a pity because the owner is pretty dedicated to doing the house properly and has spent a long time getting it all put right after the usual cement modernisations most old houses suffer from, its been turned into really impressive house.