Cavity walls and rendering

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Freerider

Freerider

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Right quick question (I say quick but may turn long)..

What is the EXACT reason people generally say that if a wall doesnt have a cavity/its single skin then you HAVE to render it (as opposed to a backing plaster).

Ive been told a couple of different reasons behind it so thought Id come here to see what you fellas thought, I personally cant see the point other than it being a precautionary measure.

cheers guys!
 
urm wall in in contact with outside wall so will draw any moisture in, this will not last long on bonding/hardwall were as sand and cement with added waterproof should hold this back for a lot longer time?
 
why would it draw moisture in if the pointing etc/ is all fine? surely if theres no cavity the bricks would have to be non porous or are they relying on waterproof render? just seems backwards to me
 
not sure mate maybe on older buildings the joints are not so good and years of weathering ect will build up and you get cold spots..either way with out that gap you seem to always have problems and a hell of a lot more with backing out in gypsum.. how many times have you repaired a window wall no cavity and its got salts all over it and looks damp and when u start hacking off you can see a clear patch of bonding were its been done before but with gypsum backing coat...........or is it just me lol
 
tell me about it Oasis, lol, Im still waiting for other peopels answers! it looks like no one f**k**g knows why!
 
hum maybe try this link

https://lmgtfy.com/?q=What+is+the+EXACT+reason+people+generally+say+that+if+a+wall+doesnt+have+a+cavity%2Fits+single+skin+then+you+HAVE+to+render+it+(as+opposed+to+a+backing+plaster).
 
nah no help lol. well maybe the rule that when building a new cavity wall you dont want to much muck falling down the gap when laying blocks and also you must use the right insulation so you dont create a bond between the walls.. something to do with having a bond with the outside ... either way render it! lol some people say why not scratch it then dab on it? what a crap idea.. still the daps get wet and it showes frew! as if the render covers all problems!
 
lol if it was scratched and then dabbed on floated then they wouldnt get wet.. bit confused by what you said dude! Im set a waterproof scratch before and then floated as normal simply because of the thickness the old render sometiems is, theres no way Id build up 3 or 4 coats to match original when you can build in one with plaster!
 
i used to think that 3-4 coats was to long and used to scratch in sand and cement then top in hardwall, but it kills the point on a non cavity wall lol.. now what i do if i have a deep wall to fill up its 2 or 3 thick coats of sand and cement render applied in one day .. dry wall wet up a small amount then lay on first thick coat.. leave for a few hours.. lay on another thick un.. then Wait around a few more hours and top off.. takes the day but the wall is done in sand and cement .. added fibers in the mix.. should be ok.. this is how CHRIS W told me how 2 deal with a single wall job like this.. u cant do 3 coats within 3-4 days!

iv done this a few times now when needed.. if it was more than a wall then i would build up over time.. but no come backs only 1 crack on 1 wall and that was due to a deep deep hole under the window were maybe i should have added some block work rather than fired in a load of render!
 
oasis said:
urm wall in in contact with outside wall so will draw any moisture in, this will not last long on bonding/hardwall were as sand and cement with added waterproof should hold this back for a lot longer time?
Click to expand...


lol Andy your right give oasis a cigar and the reason nobody else has answered it freerider is coz oasis has answered it for you.
 
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