cracking on gypsum plaster

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BIG S

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hi guys i am a new member on here.
i recently skimmed a living room and it was the old lime plaster that was in place and had to be skimmed over,the guy was well chuffed with the job now the living room has been painted and the new furniture put in place and the central heating switched back on there are some surface cracks appeared on the walls.any ideas of the problem or solutions
 
The cracks in the old lime plaster will show through the new plaster especially once the heating goes back on!
If the old lime plaster is loose/sounds hollow best to remove back to brick, as any movement will always show through the new plaster.
But too late for that now so just recommend he fills cracks then repaint.

This will work:
If they are only fine hairline cracks sand them lightly with 120grit grey sandpaper till the crack disappears don't dust off just paint over straight away with brush then when dry re roll wall.
 
Gypsum plaster dont work very well on old lime plasters especialy if the lime has cracked before.The lime plaster is on the wall because the wall is built of lime morter and lime morter walls are subject seasonal movements, lime morters are soft and can accmodate these movements whereas lime and cement morters are to hard and crack and when used externaly will let water in through and cause more damage. Lime walls should be plastered with lime morter but these days i try and talk the customer into drylining in these situations no cracking and added insulation, i have had success using one coat 10mill thick with fibre mesh embedded in it.
Lucius.
 
lucius said:
Gypsum plaster dont work very well on old lime plasters especialy if the lime has cracked before.The lime plaster is on the wall because the wall is built of lime morter and lime morter walls are subject seasonal movements, lime morters are soft and can accmodate these movements whereas lime and cement morters are to hard and crack and when used externaly will let water in through and cause more damage. Lime walls should be plastered with lime morter but these days i try and talk the customer into drylining in these situations no cracking and added insulation, i have had success using one coat 10mill thick with fibre mesh embedded in it.
Lucius.
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Thats a good bit of info but who the hell will pay to have that done? iv always over skimmed and allways seems a good job when painted. but i can see what your sayin there
 
Depending on the customer and the house Oasis some will go for the dearer option once you explain them, in this game you have to be a salesman as well, give them the options and be capable of doing them all, explain the merits of the options and nine times out of ten they will find the money for the best and dearest one and if they pick the cheapest and it does crack you tell them i told you so.
Lucius.
 
not that i can use lime plaster haha, yea i did a little sale to day. took out a bit of artex ceiling showed the woman how it had over 3 layers of artex on it, showed how heavy it was to another of cut of plasterboard(ok it was 9.5!) but she then sore the problem with and over skim so i charged just an extra £120 to board it over. jobs a better one now.
 
cheers for the info guys loads of useful ideas but i think i will need to try(nisus idea) because the room has been finished and ready for the festives.will need to tackle this in the new year.
 
Yeah go with Nisus Big its been done and what he says is good, i whent a bit of topic there. Oasis any spread can do lime work you just have to have the right attitude treat it like a lady.
Lucius.
 
We done some old lathe walls a few years back full of cracks the customer didn't want them stripped or boarded over so we pva them 1st coat skim then bedded a mesh into it then another 2 coats it worked a treat
 
did you scrim over the fine hairline cracks that were already in the original wall. if you cover them all up there's usually no more cracking then. Have bonded walls with severe hairline cracks on feature walls before then embedded fibreglass mesh in it borrowed from external render thin coat system and was bombproof :)
 
iv had a few walls with spider web style cracks all over. i did a 50/50 FINISH/BONDING MIX WITH ADDED FIBERS multi bond i called it. did the job i dint even scrim the cracks.
 
i usually look hard for any original cracks and scrim em and i use bond it instead of pva not really had a problem doing that,but i always sort any blown areas aswell.
fill em and sand em should sort them
 
Ive had a few cracks appear on the job i plastered 2 weeks ago and no in process of painting,fill with caulk wash away excess and emulsion over,sorted.
I dont no why these crakcs hapen for sure but from time to time they do
 
most plasters i talk to havnt hurd of bond it! but travis say they sell alot if it no as they did a demo of it going over gloss tiles then skimmin them! not that you want to do that!
 
it can be done but if your going to retile then just tile ontop of the bond it providing the existing background can take the extra weight
 
On old walls a strong pva mix, carlite bonding and apply mesh flatten off and multi finish, ob done and bobs ur uncle :p
 
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