Hp12

[Grooves plastering]

Hi got a render job . After painstakingly taking off defective render . It’s left brickwork in varied state of repair . Most good but Some lime motar other extended areas in hard sand cement masonry . Mostly flat it only ever had a single coat of render with a painted stipple or Terylene finish . With the advent of loads of vertical cracks which intend to crack stitch with resin and helibar system .
With the amount of Horizontal cracks was thinking the base preparation for silicon render using Hp12 and render mesh tight to substrate . Then I wanted to finish with a final coat or sand and cement float /sponge finish . Has anyone put sand cement over Hp12 base. Guessing it ain’t gone bite me in the ass.?

 

[Topspread16]

Horizontal cracks usually means wall ties have failed.

 

[Salfordspread]

Hi got a render job . After painstakingly taking off defective render . It’s left brickwork in varied state of repair . Most good but Some lime motar other extended areas in hard sand cement masonry . Mostly flat it only ever had a single coat of render with a painted stipple or Terylene finish . With the advent of loads of vertical cracks which intend to crack stitch with resin and helibar system .
With the amount of Horizontal cracks was thinking the base preparation for silicon render using Hp12 and render mesh tight to substrate . Then I wanted to finish with a final coat or sand and cement float /sponge finish . Has anyone put sand cement over Hp12 base. Guessing it ain’t gone bite me in the ass.?

Yes loads of times with either tarmac ocr or weber ocr without any problems. I've dashed with it as well as hp12 as the base

 

[Grooves plastering]

Horizontal cracks usually means wall ties have failed.

Agree but it’s solid 9” walls

 

[bobski]

Hi got a render job . After painstakingly taking off defective render . It’s left brickwork in varied state of repair . Most good but Some lime motar other extended areas in hard sand cement masonry . Mostly flat it only ever had a single coat of render with a painted stipple or Terylene finish . With the advent of loads of vertical cracks which intend to crack stitch with resin and helibar system .
With the amount of Horizontal cracks was thinking the base preparation for silicon render using Hp12 and render mesh tight to substrate . Then I wanted to finish with a final coat or sand and cement float /sponge finish . Has anyone put sand cement over Hp12 base. Guessing it ain’t gone bite me in the ass.?

No


Wouldn't do it

Hp12 is high polymer and has a fairly good amount of flexibility. Spoke to their tech a few years back, and we concluded it'd be around 4 to 1 ish (adjusted and with the additives.......)

If you s+c over it you'd probably need at least 1.5l of sbr per guage, to maintain give, and to also make sure that the mix is weaker than 4.5 to 1, It'd be a ball ache

They have a gp mortar that may work?

 

[Salfordspread]

No


Wouldn't do it

Hp12 is high polymer and has a fairly good amount of flexibility. Spoke to their tech a few years back, and we concluded it'd be around 4 to 1 ish (adjusted and with the additives.......)

If you s+c over it you'd probably need at least 1.5l of sbr per guage, to maintain give, and to also make sure that the mix is weaker than 4.5 to 1, It'd be a ball ache

They have a gp mortar that may work?

Gp mortor is exactly the same as tarmacs or weber ocr is all pre bagged s/c . I've never had any problems tbh

 

[malc]

Horizontal cracks usually means wall ties have failed.

Wall ties failing is common if the property is within a few miles of either a salt marsh or salt water.

 

[bobski]

Gp mortor is exactly the same as tarmacs or weber ocr is all pre bagged s/c . I've never had any problems tbh

They're OK

All ocr's should be ok as they usually have lime and additives to give them 'give'

Normal s+c (without decent lime or sbr) could be agg and too rigid for him to coat over with.

 

[Salfordspread]

Agree but it’s solid 9” walls

It'll be fine . If you listen to half the dickheads advice on here pal you'd end up in the fooking nuthouse . Ha ha

 

[Salfordspread]

They're OK

All ocr's should be ok as they usually have lime and additives to give them 'give'

Normal s+c (without decent lime or sbr) could be agg and too rigid for him to coat over with.

Yes I agree but who on earth these days mixes there own s/c when you can buy it pre bagged ever mix perfectly gauged ??

 

[bobski]

I usually price it in,

Unless it's a special case or unusual work, or if there's s**t loads of dubbing out.....


Bagged gear as you know is generally decent with consistent set times,


Gone are the days you're at the bottom of a big flank wall in looking at soaking wet render that refuses to rub up (in cold temps.)

f**k**g about with newspaper tricks and s**t....