on our systems we fill the joint with high module mastic.
K Rend Hairline cracks
- Thread starter Munners
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on our systems we fill the joint with high module mastic.
Rigsby
TPF Special Forces
Stop beads under the sill and either a cut around the sill and frame with a small tool or if poss 1mm strip of sticky back foam used for upvc work.
BTAPlastering
New Member
Ivory k-Rend
Cracks.....
I have just rendered 90+ Sq/mtrs onto block work and had cracks on all south facing walls. I didn't use any mesh but I did use the K-Rend TC product (which is the same as thistle bond-it). This problem occurs even with Webber so it isnt the product and it also happens to sand/cement
When the mix was 'too wet' it cracked lots, where the mix was on the 'dry side' there was only the odd crack.
I experimented with ways of repairing it. I found that getting on it the next morning after application is best. What I found worked for me was wetting the crack with rad brush leave the water to work in a few mins then dampen the whole area around the crack with a sponge float. Then get a handful of dry k-rend straight out the bag & just throw it at the crack and rub it around the area with your hand (wear gloves!!) you will find it fills the crack and blends well. leave to dry for a bit and with a damp sponge float just go over it.
I think the cracking is caused when the surface dry's creating a crust, when the render behind drys it goes tight and stresses the top surface, causing it to crack. One comment on here mentions the walls being a thermal store and this is very true and can cause the same effect. The wind will dry the surface fast also.... This is a very common problem!
One thing I have found which helps better than anything is get your timing right before you flatten off.
If you spray on: leave the render rough till it is nearly dry before you rule off with straight edge.
If you apply by hand: leave the surface broken so it can dry slightly before you close the face with your trowel.
dry is better than too wet... you can always dampen down a wall if it is too dry using a sponge float, if you need to.
SBR...
What you did with the SBR is a fine but remember when you use SBR you create a barrier which stops moisture. Usually the moisture in render will be 40% absorbed through the block work itself but if it has SBR on it cannot do this! meaning that the render slips around and also stays wetter longer. Which I mention above causes cracking... I hope this is helpful
This is not written in stone, I am not preaching! it is just from based on my observation whilst rendering
Cracks.....
I have just rendered 90+ Sq/mtrs onto block work and had cracks on all south facing walls. I didn't use any mesh but I did use the K-Rend TC product (which is the same as thistle bond-it). This problem occurs even with Webber so it isnt the product and it also happens to sand/cement
When the mix was 'too wet' it cracked lots, where the mix was on the 'dry side' there was only the odd crack.
I experimented with ways of repairing it. I found that getting on it the next morning after application is best. What I found worked for me was wetting the crack with rad brush leave the water to work in a few mins then dampen the whole area around the crack with a sponge float. Then get a handful of dry k-rend straight out the bag & just throw it at the crack and rub it around the area with your hand (wear gloves!!) you will find it fills the crack and blends well. leave to dry for a bit and with a damp sponge float just go over it.
I think the cracking is caused when the surface dry's creating a crust, when the render behind drys it goes tight and stresses the top surface, causing it to crack. One comment on here mentions the walls being a thermal store and this is very true and can cause the same effect. The wind will dry the surface fast also.... This is a very common problem!
One thing I have found which helps better than anything is get your timing right before you flatten off.
If you spray on: leave the render rough till it is nearly dry before you rule off with straight edge.
If you apply by hand: leave the surface broken so it can dry slightly before you close the face with your trowel.
dry is better than too wet... you can always dampen down a wall if it is too dry using a sponge float, if you need to.
SBR...
What you did with the SBR is a fine but remember when you use SBR you create a barrier which stops moisture. Usually the moisture in render will be 40% absorbed through the block work itself but if it has SBR on it cannot do this! meaning that the render slips around and also stays wetter longer. Which I mention above causes cracking... I hope this is helpful
This is not written in stone, I am not preaching! it is just from based on my observation whilst rendering
xyzplasterer
New Member
Only time I've seen it crack is where it's been put on 2 thick and slumps.
xyzplasterer
New Member
What were you going over? Did you kill too much of the suction with the SBR causing it to slump? I've done it many times over Sand/cement with cementone integral waterproofer 4-1 scratch. Dampen down the scratch before applying...never had a problem, have seen it crack where it's put on too thick though.
xyzplasterer
New Member
Cracks.....
I have just rendered 90+ Sq/mtrs onto block work and had cracks on all south facing walls. I didn't use any mesh but I did use the K-Rend TC product (which is the same as thistle bond-it). This problem occurs even with Webber so it isnt the product and it also happens to sand/cement
When the mix was 'too wet' it cracked lots, where the mix was on the 'dry side' there was only the odd crack.
I experimented with ways of repairing it. I found that getting on it the next morning after application is best. What I found worked for me was wetting the crack with rad brush leave the water to work in a few mins then dampen the whole area around the crack with a sponge float. Then get a handful of dry k-rend straight out the bag & just throw it at the crack and rub it around the area with your hand (wear gloves!!) you will find it fills the crack and blends well. leave to dry for a bit and with a damp sponge float just go over it.
I think the cracking is caused when the surface dry's creating a crust, when the render behind drys it goes tight and stresses the top surface, causing it to crack. One comment on here mentions the walls being a thermal store and this is very true and can cause the same effect. The wind will dry the surface fast also.... This is a very common problem!
One thing I have found which helps better than anything is get your timing right before you flatten off.
If you spray on: leave the render rough till it is nearly dry before you rule off with straight edge.
If you apply by hand: leave the surface broken so it can dry slightly before you close the face with your trowel.
dry is better than too wet... you can always dampen down a wall if it is too dry using a sponge float, if you need to.
SBR...
What you did with the SBR is a fine but remember when you use SBR you create a barrier which stops moisture. Usually the moisture in render will be 40% absorbed through the block work itself but if it has SBR on it cannot do this! meaning that the render slips around and also stays wetter longer. Which I mention above causes cracking... I hope this is helpful
This is not written in stone, I am not preaching! it is just from based on my observation whilst rendering
I take it you do these crack repairs after scraping?
FourInchesWide
Member
Do window-sills expand when hot from the sun??
I'm asking as I've never heard of this being an issue/problem. I could see it being some sort of elaborate extra on some Govt. build or millionaire home to form a nice joint where two different materials meet and thus hiding the usual hairline crack/joint.
FourInchesWide
Member
Cracks.....
I have just rendered 90+ Sq/mtrs onto block work and had cracks on all south facing walls. I didn't use any mesh but I did use the K-Rend TC product (which is the same as thistle bond-it). This problem occurs even with Webber so it isnt the product and it also happens to sand/cement
When the mix was 'too wet' it cracked lots, where the mix was on the 'dry side' there was only the odd crack.
I experimented with ways of repairing it. I found that getting on it the next morning after application is best. What I found worked for me was wetting the crack with rad brush leave the water to work in a few mins then dampen the whole area around the crack with a sponge float. Then get a handful of dry k-rend straight out the bag & just throw it at the crack and rub it around the area with your hand (wear gloves!!) you will find it fills the crack and blends well. leave to dry for a bit and with a damp sponge float just go over it.
I think the cracking is caused when the surface dry's creating a crust, when the render behind drys it goes tight and stresses the top surface, causing it to crack. One comment on here mentions the walls being a thermal store and this is very true and can cause the same effect. The wind will dry the surface fast also.... This is a very common problem!
One thing I have found which helps better than anything is get your timing right before you flatten off.
If you spray on: leave the render rough till it is nearly dry before you rule off with straight edge.
If you apply by hand: leave the surface broken so it can dry slightly before you close the face with your trowel.
dry is better than too wet... you can always dampen down a wall if it is too dry using a sponge float, if you need to.
SBR...
What you did with the SBR is a fine but remember when you use SBR you create a barrier which stops moisture. Usually the moisture in render will be 40% absorbed through the block work itself but if it has SBR on it cannot do this! meaning that the render slips around and also stays wetter longer. Which I mention above causes cracking... I hope this is helpful
This is not written in stone, I am not preaching! it is just from based on my observation whilst rendering
So what does that tell you about the cause of the cracking? Seems clear to me. ;-)
Karansahiba81
New Member
Hi friends I'm new in this side I'm builder we done k rend 4 weeks ago proper my Jamaican friends he have more then 20yrs experience now new k rend hair line some main front wall so plz give me suggest what I do my name Karan Singh frm west london
This can't be emphasized enough with the FT. All polymer renders will treat you better with a good long mix.
plasterjfe
Private Member
Is ft actually classed as a polymer render though ? Is the content at the percentage level.
Its nothing like powerwall or m1 that have polymer render classification.
Got a wp job on. Can't be sprayed wp so will be doing 7bag mixes in the barrel. Mixed twice as before.
Anyone using krend hand app?
If you ever try egrade but hand app it? Its much nicer gear to work with and still silicone
stuart23
Private Member
What's the difference with normal and egrade?
dieselpower
Active Member
Yeah, hand applied 2 pallets of it after machine was sold. Pretty nice to put on. Then had to put wp ivory on and it was like where's the plasticiser , it was dead..
plasterjfe
Private Member
Normal is dead as diesel says. Its very coarse gear but doesn't seem to bind as well as others. The egrade is more like the others.
Egrade is the sprayable version of silicone ft.
Sprays hellish once you get the d4.2 on the machine
I suggest you buy an English dictionary for a start.
KRend Roughcast Cracking in Scotland
I recently had an experienced plastering team apply KRend roughcast to the stripped brick exterior walls of a house in Oban, Scotland. Everything including preparation seemed to be done by the book and as per KRend instructions; and weather conditions were excellent.
However, within 48 hours very extensive cracking was observed over the whole wall surface. (See attached photo).
Does anyone know the cause, and mo
re particularly, the fix?
Mant thanks for your help.
I recently had an experienced plastering team apply KRend roughcast to the stripped brick exterior walls of a house in Oban, Scotland. Everything including preparation seemed to be done by the book and as per KRend instructions; and weather conditions were excellent.
However, within 48 hours very extensive cracking was observed over the whole wall surface. (See attached photo).
Does anyone know the cause, and mo
re particularly, the fix?Mant thanks for your help.
User___removed
Well-Known Member
It looks to me that it has dried to quick.
User___removed
Well-Known Member
If they are surface cracks and the gear is not pulled off the wall,paint could be used to close them in
It is a viable option with the first 14-24ish hours of application, with all renders.
I realise you may have had a bad experience but there are applicators out there that swear by the stuff and do actually enjoy applying it.
The silicone range isn't designed to be the easiest to apply on the market, it never has been but the private punters get attracted to the word "silicone" rightly or wrongly. Where most applicators go wrong is charge the same labour rate to stick the stuff on as the easier basic renders then get their knicker in a twist when they aren't in the pub by four.
If a punter wants silicone be straight up, tell them the silicone makes application more complex, mixing time is effectively doubled and you will have to put more effort in to get a good spread and you want a few extra quid a metre. Now you have the extra cash as punters will pay it in my experience make sure you read the datasheet and do what it says and approach the job with a different frame of mind.
Getting a 25 year BBA cert ain't easy, the gear is tested to within an inch of its life in the lab and you need real life examples of the product doing what you say it does. There's a reason others only offer 10-15 year guarantees.
If your having to fill out 'shrinkage cracks' with dust it is an inferior product.
User___removed
Well-Known Member
I've just started using parex and hav'nt seen a crack in any of the jobs I've used it on
Your teaching me to suck eggs pal,
Its nothing to do with ease of application.
Make that multiple bad experiences with k-rend. Be it bad batches to shrinkage etc it wasn't an isolated incident and the back up service is poor. There are far better bagged renders out there I've used everyone one out there on every differnt sort of project, it's not just me saying this, look at other posts on here, we used to use a lot of k rend but don't use any now.
Im fully aware of how BBA's work I've been involved with render companies at a decent level, I also employ quite a few lads both on the books and subbies and spend over a £100,000 a year on render so I know what I'm dealing with, I'm not working out the back of a van doing the odd wall with the gear. The k1 has been a nightmare for K rend as it has had a lot of bad feedback, and recalled gear.k rend want my business, I've got 2 full pallets of k rend given to me for nothing by k rend direct and I've resisted the option of using even though it's for nothing, that for me tells the story.
Jimbob9
Active Member
Don't get me wrong, I fill a lot of cracks and I certainly don't use dust.... I don't just fill k rend either.
Rhys
Well-Known Member
Scott McCracken (said he was a member on here..) came down to our local MKM merchants on Thursday and was very interesting to listen to. They are going to be stocking 3 basic K-rend colours and so had a good chat with him (only us and one other turned up to see him).
Talked a good talk so much we are thinking of going to Larne for the course (looks like a good course as well). Seams like a lot of folks on here are quite negative towards K-rend, though some positive. Going to have to have a trawl through old posts to read into it.
Talked a good talk so much we are thinking of going to Larne for the course (looks like a good course as well). Seams like a lot of folks on here are quite negative towards K-rend, though some positive. Going to have to have a trawl through old posts to read into it.
I know it doesn't seem like it but I'm agreeing with you to some extent.
The FT isn't the easiest to apply gear, in fact compared to other lower cement content that don't have to wrestle with silicone in the mixer renders it can be a complete pain in the arse at times, but, it is a big seller, especially to the private market which isn't so price driven and you can make it work to your benefit.
Yeah, he's one of their area reps.
spunky
Private Member
It slumps by hand and k1 is full of hairline cracks you can't fill apart from that it's an excellent product
it's never been good and the support you get from reps speeks volumes about how they give a **** about how much money you be lost and how someone's house has been ruined, I'm surprised there not in rogue traders it really is that bad
it's never been good and the support you get from reps speeks volumes about how they give a **** about how much money you be lost and how someone's house has been ruined, I'm surprised there not in rogue traders it really is that bad
spunky
Private Member
What a surprise
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