Rendering over masonry paint

[dmbarlow]

Hi, last year my missus decided to paint the exterior of our house with masonary paint. She has now decided she wants it flat rendered. I have taken a plastering course, been furiously practicing my plastering round the house, and rendering on the garden walls with 3:1 scratch coat and 4:1 float coat. I am almost getting it smooth enough (and quickly enough!) to consider having a go at the house.

Will I be able to get away with just PVA and or keying with my angle grinder - I am getting all sorts of different advice from 2 coats of PVA to wire meshing everything! Same for mix!

Thanks

 

[oilman]

What is your house made of? How old is it? Masonery paint and cement rendering (even seperately) are the death knell for many houses.

 

[dmbarlow]

Front facia was rebuilt in'modern' brick about 20 years ago, side facia is some sort of stone (possibly granite) block for the first story, and original brick ( all circa 1860) for second story, rear facias are all original brick.

The reason for all this is to try and get the highly visible front and side facias looking uniform rather than the mish mash of modern/old brick and stone.

 

[legs-akimbo]

Would probably not be a good idea to render stone work at all, brick ok with raked out joints and a spatterdash coat of 1:1.. one of oilmans pet hates so he may explain why!!
However nothing looks worse than a poorly applied external rendercoat and far from enhancing your property you run the risk of devalueing it by thousands.

 

[dmbarlow]

Would I get away with a slush coat here? A spatterdash coat would be costly giving the area to be covered. Also, any thoughts on the angle grinder to get a key?

 

[legs-akimbo]

by spatter dash/ scud I mean a watery mix of 1:1flicked onto the exposed bricks with a square ended trowell to provide a key for the following scratch coat

 

[dmbarlow]

Thanks guys.