Sand stone patching

Status
Not open for further replies.
T

tree

New Member
I was wondering if any of you have experience patching sandstone (to be painted obv), dunno whether to use pva or sbr, and any other tips ? Some of it's so far gone I'll need to mesh and shutter it out . The lady's been quoted about 40 grand to re[lace with new stone, and that's not an option, so muggins here's agreed to make it good. Thing is, I'm a bit worried about getting it to stick.

Cheers for any feedback :)
 
It's the windows on an old victorian number, lime pointed bricks, so the damp can breathe out the walls as it should do, no worries patching with s & C then. It's a tricky job, i'll need to build it up to get the lines and make it contingent. Just want to be sure it sticks !
 
Try using an angle grinder to give it a deep key and as you build it out remember to start with a strong mix and get progressively weaker. Not sure about the shuttering idea, you will just end up with one heavy lump. And finally, a lot of people use S B R as an adhesive/sealer but in fact it's a hardener, PVA all day long
 
lime will eat into sandstone.
you can purchase reformed sandstone window heads and jambs, about £100 per set.
 
Hi tree, I use Lithomex stone repair mortar, basically a lime & natural cement mix bought pre bagged when coloured and used correctly is nearly impossible to see the repair from 6 inches away. Its 5mm minimum thickness and can be shaped as a wet mortar or tooled like a sandstone when set completely. Its not cheap, so we block out right up to almost the 5mm face using lime render and lithomex over the top of that to finish. Its the best ready made sandstone repair product on the market by far. It may be an option rather than painting. Silicate paint is what we would use for masonry mostly Keim.

Regards
 
Edit - no pva or sbr, just water and not over the top of Portland cement repairs. Dress back surface 5mm using scutch tool and apply back to face - 5mm is minimum as it doesn't feather away & will loose its strength and colour
 
Marko1960 said:
Try using an angle grinder to give it a deep key and as you build it out remember to start with a strong mix and get progressively weaker. Not sure about the shuttering idea, you will just end up with one heavy lump. And finally, a lot of people use S B R as an adhesive/sealer but in fact it's a hardener, PVA all day long
Click to expand...

Wrong about sbr and i wouldnt dream of using pva outside
 
Lime eating in to sandstone!!!!!!??????:RpS_lol:.. well I thought I'd heard it all...wow!!!!!

and PVA instead of sbr for external use!!!!!:RpS_cursing:...

Seriously Please if you CLEARLY don't understand the materials you are using do not give wrong advice and mislead people.

Over time water adulterates PVA and breaks in down, PVA should only ever be used to control suction internally when working with gypsum plasters and highly dilute mixes at that, NEVER externally in exposed environments!!!

As for the comment on Lime, I am lost for words...sandstone (quartz or silicon) being adulterated by calcium hydroxide..:RpS_confused::RpS_unsure:...we use sand in our lime mortars, we bed sandstone on lime mortar.. :RpS_lol:
 
Status
Not open for further replies.

Share this page

Back
Top