K Rend Spec Help Needed For New Job

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livbuilders

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Hi guys

We've been asked to price a job using Krend. The surface at the moment is made from prefab concrete which has had some sort of textured finish applied to it.. Looks like a textured paint... Sandex possibly.

We can't hack anything off because the texture on the prefab concrete is only about 2 to 3 mm. There's quite a bit of meterage to cover as well.

So what would you guys suggest by way of preparing the surface for K Rend?

SBR first or is there a better way of prepping this. Also, would we get this out of one coat K Rend or is a base coat required.

Thanks, new to pricing for K Rend so your help and advice appreciated.

Adam
 
the problem you have is the paint. in nearly all cases you should really remove all of the paint, nothing is as good as removal. the coating on the surface also may well be an elastomeric masonry coating = more bad news, it will resist bond with most products. krend wont stick thats for sure you will need to use a pre-treatment
 
Pre - treatment? Any more on this. Would SBR not prepare it or is something else required? How about if we mesh the surface first?

Cheers
 
Just wanted to say thanks for these replies guys. We've used EML on a few jobs and the guys hate working with it. On the job we are pricing on there is about 350 M2 so EML isn't really going to make people smile. At least not the guys applying it (Cutting, drilling and plugging it to concrete panels), but more so the developers we have to give the price to. The EML cost will probably be the straw that breaks the camels back. Was hoping to be able to keep cost at lowest margins to secure the work.

The cost between the EML route and just trying to stabilize the substrate in some way is going to be significant. Will be interesting to see what the developers think when they see the price comparisons!
 
I did and that's what they said you could scabble the paint off I bet it would piss off then you could hpx might have to prime it and render you have to way up the materials and the labour
 
livbuilders said:
Just wanted to say thanks for these replies guys. We've used EML on a few jobs and the guys hate working with it. On the job we are pricing on there is about 350 M2 so EML isn't really going to make people smile. At least not the guys applying it (Cutting, drilling and plugging it to concrete panels), but more so the developers we have to give the price to. The EML cost will probably be the straw that breaks the camels back. Was hoping to be able to keep cost at lowest margins to secure the work.

The cost between the EML route and just trying to stabilize the substrate in some way is going to be significant. Will be interesting to see what the developers think when they see the price comparisons!
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TBH mate EML is just part and parcel of rendering sometimes, probably doubt anyone likes doing it but thats life. If your not that interested in going to the extent or cost of EML or removing all the paint completely why ask the question at all ? just lash the krend over the top and have done with it maybe ?

concrete is a mare to adhere to anyway, concrete with a weatherlastic paint could mean render sliding off the wall.

Is it poss to hire a hilti gas gun a fire the EML on ? or give the client 2 prices - one for doing it properly and one for cost/speed ? that way you have given them the option before you do anything that could need a call back in the future like
 
Is it possible for you to mechanically fix 25mm phenolic board and apply a thin coat system, would probs work out as cheap as fixing eml and look nicer longer imo
 
does it have to be k rend finish?

go over the existing with parinter and a thin coat system incorporating alkaline mesh, we did this on a project last year over sandex
 
20% less cost than matie aswell,
weve used it on a few substrates that have been painted, its one of the best adhesives out there.
 
Tell me more about this Parinter stuff? I asked a question last week about a thin coat over the existing. A big block of flats near me got a thin coat render over the existing that was painted. Still on but what a crap job they made of it. I thought it would have blown by now but no!
 
Rigsby said:
Tell me more about this Parinter stuff? I asked a question last week about a thin coat over the existing. A big block of flats near me got a thin coat render over the existing that was painted. Still on but what a crap job they made of it. I thought it would have blown by now but no!
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what do you want to know about it?

similiar build up to maite but with hydrated lime,dries quicker than maitie and is a bit more tougher to put on I find.
but amazing stuff it sort of anchors in to painted surfaces.Youd think it would 'shell' off a gloss surface but it doesnt shift, incorporate 355 mesh with it.
 
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correct,
but aslong as you follow the spec and the paint is sound youll have no issues, its only around 6mm of aditional render in anycase.
 
Parinter is a 3mm min coat plus acrylic at anything from 1mm up so not alot of weight there. loads of lime in it too so will allow for expansion/contraction.
 
pwi said:
Parex and I think owls is talking about the 5 mm mesh
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yep 355 is the 5mm gear.
tip for you tho. if your buying parex mesh [green in colour] shop around for it, as the difference from supplers can be as much as 20 quid a roll
 
For k-rend prep i personaly would use a refina powerprep which you can hire, this wil help scabble paint, and give a key, then k-rend basecoat with alkaline mesh embedded.
 
only way you will be able to render over existing painted surface will be to either remove 90% (need to scabble this off existing surface) of the paint, then use k rend HPX polymer modified basecoat with mesh then silicone topcoat.

alternatively, you can render directly onto this with the HP12 basecoat / and or HPX with mesh , whilst still wet drill & mechanically fixed to the substrate (1 in 9 should be stainless steel) in a diamond pattern at 450mm centres & immediately overcoat with a further 2-3mm of the HPX / and or HP12 basecoat.
 
Alexander said:
only way you will be able to render over existing painted surface will be to either remove 90% (need to scabble this off existing surface) of the paint, then use k rend HPX polymer modified basecoat with mesh then silicone topcoat.

alternatively, you can render directly onto this with the HP12 basecoat / and or HPX with mesh , whilst still wet drill & mechanically fixed to the substrate (1 in 9 should be stainless steel) in a diamond pattern at 450mm centres & immediately overcoat with a further 2-3mm of the HPX / and or HP12 basecoat.
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Sound advice but have you not read the above? Parinter for sound painted surfaces....
 
hi lads i have got to price a k rend job of 200m2 onto concrete block with scrapped finish is it straight on to block or spr first would you apply both coats in same day and then scrape in the morning each section is about 35 square and we are a 2 and 1 gang cheers
 
gtp said:
hi lads i have got to price a k rend job of 200m2 onto concrete block with scrapped finish is it straight on to block or spr first would you apply both coats in same day and then scrape in the morning each section is about 35 square and we are a 2 and 1 gang cheers
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another one.
 
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