Cracking Paint in corners again!

[darren7]

Hello, Plaster is 6 months old and i have thined thge paint down and even tried flexi decorators filler in the corner..

Dulux trade V matt, I have even just user the tip of the brush just to use a tiny bit of paint, but it is still giving tiny hairline cracks..... even with really little thin paint....

What next guys

 

[Third_Eye]

1/ Is the walls that are Plastered over Gyproc ? 2/ Is the walls that are Plastered over Plaster over bricks ? 3/ Is the walls that are Plastered over 1 & 2 above ? 4/ Was there already cracks in the internal corners before it was re-plastered (if it was re-plastered) ? 5/ How much was the first coat of emulsion thinned down by ? 6/ What make did u use on first coat ?

 

[darren7]

its Platerboard, over MDF, its around like a false fite place.... so its built up of MDF, then 18mm Plaster board, then just to the wall, skimmed brick.

Its not like a crack that you see when someone has not used tape over the joints in the board, its just really fine ones like every few inches... like the paint is too thick.... but ive just put it on s light..

first coat about 30% water....Dulux trade again, ...Ive even tried to pva the corners....

Darren

 

[Third_Eye]

Ok, did u thin the second coat ?

 

[darren7]

yes I have always thinned the coats, 20-30% as the Trade is thick.... why is this doing it?

and is there a solution

D

 

[Growler]

Perhaps if you stop thinning the stuff and put it on neat, you might get a better result.

 

[Third_Eye]

I find when using Dulux Trade Vinyl Matt over new/bare Plaster, that the first coat must be thinned down by 25%. However, the second is best thinned down by 10%. I have also seen the problem you mention with Dulux Trade Vinyl Matt, in terms of cutting in but it caused by using Dulux Trade Vinyll Matt neat. Another way it can happen is if a kettle is being used in a corner and the steam from the kettle penetrates the brush marks and causing it to split. It can happen by radiators in terms of the heat coming from them. It can happen by the plaster being over polished also !

 

[confidentincompetent]

Sometimes It may be plaster has been overtrowel'd and fatty bits have collected in corner. Or! if acrylic fillers (decorators caulk) was used (?) the paint film on matt paint splits.. I prime any caulk filled areas such as ceiling/walls and corners where emulsion is the finish....with solvent based undercoat (thinned). Seems you got a Mud cracking effect and any waterbased paint will just keep cracking..Try a thinned coat of solvent based undercoat over the crack. This will stabilise the surface ready for emulsion......
Good Luck...

 

[dingo1959]

third eye we meet again over the years i have always used stabiliser over wall and ceiling surfaces before painting and even after papering with liner as i have had a huge tin of it laying about, is this a good idea? extra work but seems to work for me

 

[Third_Eye]

Send a pic of the corner if u can ? Though "confidentincompetent" may have give u a fix "dingo1959" !