Will this application fail

[Tessa]

Hi,
I am getting some interal work done and the builders are putting lime plaster on my walls.
The plaster is from Ty Mawr and is being applied to wood wool boards which have been applied over wood battons which are fixed to the old solid brick walls.
The plaster came last week and on Wednesday they applied the first coat, which was hemp and lime on the wood wool boards, and a lime coarse render on the bathroom walls where the brickwork was in poor condition which made it hard to fix the woodwool boards.
The next day they told me they applied the finish coat.
Now these are my concerns. If they thought the first coat was dry then i am concerned they did not wet the brickwork in the bathroom. And i understand there needs to be enough time for the first coat to carbonate before the next coat is applied. I am guessing the plasterer has never worked with lime before and is just treating it like gypsum.
Is there any chance this application technique will be ok or is it inevitable it is going to fail and i need to get the builders to redo it?

Also as i am running out of money i am going to need to render the exterior of the building myself once the frost has passed. There is an extension at the back to the ground floor. This is of blockwork and needs to be lime rendered to match the upper storey which is the old original victorian brickwork which is very soft and porous and badly spalled under the old concrete render.
Can anyone advise on what lime to use and what technique to render these two substrates externally?
Many thanks
Tessa

 

[superspread]

Hydraulic lime.lime is lime

 

[DannyMac]

They should have let the backing coat of hemp lime go knuckle hard ( meaning you are unable to push your knuckle into it) before applying the finish coat. This will take a fair time this time of year, 1mm a day if you're lucky.

There will be quite a bit of shrinkage of the backing coat and it's important that this occurs before the finish coat is applied. There are other reasons too.

Are they using fine lime hemp to finish with? How are they leaving the backing coat? Why did they batten out the walls instead of applying directly onto the bricks?

 

[Tessa]

I think the idea of putting it on to wood wool boards was to make it easier to get a good finish, i really dont know, i guess for the reason they sell the wood wool boards to plaster onto.
But given the situation is there anything that will help to ensure the application doesnt fail, if all else fails and it cracks could this be remedied by adding another top coat?
Thanks

 

[DannyMac]

Yes

 

[seanlar]

for your outside render use fat lime(lime putty)ready mix two coat haired /course stuff will work fine ......Traditional Lime Plastering Building Restoration

 

[Tessa]

Thanks for that Seanlar. Do i need to apply some sort of mesh to the blockwork to give some sort of surface for the plaster to grip onto?

 

[seanlar]

no no ...no metal mesh just rake out the joints for a good key and a good wet down and off you go and plenty of hair in the first coat sticks like sxxt let me no how you get on rgs sean www.plasterinlime.co.uk

 

[Render Systems]

OOPs you have been screwed tessa... it will all fail... it will drop off like a ice cream on a summers day leaving the cone... ANY lime work needs time for each coat to carbonate... the only stuff that sets over night is cement mortar... and thats no good for your job... get back on to the specifiers and the plasterers and sue them all or get them to write a system specification as most normal people would do before letting cowboys take your hard earned money

 

[martinemj]

outside rendering best done with nhl.lime for faster set ..esp bearing in mind our
weather .