Crumbling Bay Window Pillars

[lymmboy]

Hi, I'm looking for some advice

I wanted to repaint the exterior bay window masonry only to find a fair amount of deterioration in the stone, which i think is sandstone,
I started to dig out the affected area with a screw driver and found the problem is worse than i thought, there are several patches where the stone is very soft and damp and comes off in large chunks, i'd say the rotten stone goes about half an inch deep until it reaches the hard undamaged stone.

The question is, can i repair this myself and if so, how? or will i have to have the pillars replaced?

I have taken a couple of photos of the worst affected areas

http://i478.photobucket.com/albums/rr145/lymmboy/DSC00038.jpg

http://i478.photobucket.com/albums/rr145/lymmboy/DSC00039.jpg

Any help and advice greatly appreciated, Mick

 

[Symptoms]

Mick - if you're confident with a trowel do it yourself.

Knock off all the friable stuff & strip-off all the paint to the affected column. Fix any leaks from gutters, etc. Use epoxy repair mortar (epoxy patch mortar), although it could be done with a sand/cement mix. Fix wooden battens to create an edge to work to - do one face at a time and let the mix dry then move onto the next face.

An alternative would be to remove all surface material, fix plaster angle bead (external grade) then render all the faces in one go with sand/cement render. This is the method I'd use; in a sense you are creating a whole surface to the column and not patching.

 

[lymmboy]

Thanks for the reply Symptoms,

I think i'll go for the first option, i'm ok with a trowel and the idea with the battens sounds just the job, i would never have thought of that!

Cheers for the advice mate.

P.S would i need to pva the sandstone or treat it with anything before i apply the new mortar?

 

[diyisfree]

NO NO NO dont put PVA externally.