Render job!

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Dirtybill

Dirtybill

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Just started a job on an old farmhouse, the client is wanting all the old existing roughcast (wetdash) which is coming off in sheets stripped and re done in a wetdash. The stonework underneath is in pretty decent nick except from the corners which have opened and have blown, my intentions are

A. To sbr the whole house then spatterdash for key (or should i slurry it?)
B. Block it all out
C. Scratchcoat with a 4-1 mix with quarter bucket of lime through
D top coat as normal, should i use lime in the topcoat and am i correct in saying i do not add any admix to any of the coats?


Any help, guidance would be appreciated as i dont want this one to come back and bite me in the arse!


All i need now is the weather to be kind:RpS_scared:
 
this has to be done with NHL 3.5 lime render NOT CEMENT based render, is this will trap the water and come off again after making the house seriously damp again... do a 3 coat system 10mm dub out coat 10mm float coat and 3-5mm top coat but dont touch it at this time of the year as it will never set and just cause major headaches
 
no sorry mate if its a solid wall with no cavities you will do more harm than good if you render with sand and cement thats why the old stuff is coming off in sheets, you have to replace with NHL 3.5 lime render this render allows the walls to breath and doesnt trap the water have a look at this job i did in barbados the house was damp as fcuk and the walls were 4ft thick we had to take all the old render off and put Lime mortar back on the house is now dry as a bone
 
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Its good to have you back on the forums Render Systems. Your posts are top notch!

Just wish i could understand what
your saying in the vids :RpS_biggrin:
 
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No hydrated lime is totally different to NHL (Hydraulic Lime) DO NOT USE SAND AND CEMENT WITH HYDRATED LIME..... USE NHL 3.5 ONLY if you use cement you will fcuk the building up completley
 
Im sorry mate but as much as i appreciate your advice i have been taught to always use cement with hydrated lime in exterior work and i have in the past and had no problems, i wanting to let the building breathe thus eliminating the dampness, maybe im getting it all wrong!
 
Its horses for courses, render systems is 100% right sand & cement even with lime in it is the wrong product for that job.
Go and do a couple or days course in lime render( yes its different) then go back in the spring.
And up your price by 500%
 
Bill I may just be a really lucky bloke but my cottage was built in 1807 with solid walls of soft reds. The external render is two coats of S&C and the inside is also floated out with S&C. The cottage being thatched doesn't have any gutters so there's plenty of water laying about when it rains and yet we don't have any damp issues and the render is in good nick. Like I say I may just be lucky.
 
Render Systems said:
this has to be done with NHL 3.5 lime render NOT CEMENT based render, is this will trap the water and come off again after making the house seriously damp again... do a 3 coat system 10mm dub out coat 10mm float coat and 3-5mm top coat but dont touch it at this time of the year as it will never set and just cause major headaches
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sorry, i remember this coming up a while back when somebody had put lime over cement render but i cant think who it was. he was a very bad boy
 
essexandy said:
Bill I may just be a really lucky bloke but my cottage was built in 1807 with solid walls of soft reds. The external render is two coats of S&C and the inside is also floated out with S&C. The cottage being thatched doesn't have any gutters so there's plenty of water laying about when it rains and yet we don't have any damp issues and the render is in good nick. Like I say I may just be lucky.
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Andy, i know shed loads of old cottages around here which are the same as yours and still as good as when they were done in sand and cement but they must be all lucky as well , maybe its the cider we put in the mix.
 
dirty bill.. i am sure you can get a specification of a render manufacturer for the work you need to do. The main purpose of using lime is your walls are breathable. A bonding or priming agent will be the first thing installed followed by a breathable base coat topped with a breathable dash reciever and roughcast mix. lime is expensive and difficult to install quickly which is a pain this time of year
 
Lime would perhaps be the ideal system to use, but if you were to present the options to the customer (cost/timescale being the over-riding factor in 90% of cases) I'm sure they will be happy to have a S & C render applied - especially when you tell them it will last at least 20 years anyhow.
 
Dirtybill said:
Im sorry mate but as much as i appreciate your advice i have been taught to always use cement with hydrated lime in exterior work and i have in the past and had no problems, i wanting to let the building breathe thus eliminating the dampness, maybe im getting it all wrong!
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Well just do it how you intend to do it i dont know why you ask for advice if you wont take it... but be warned it will come back and haunt you
 
Settle down hen, see post 16 :RpS_thumbup:


I will leave the lime out it, scud the **** out it and hope for the best
 
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