Render strength??????????

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Arti

Arti

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Hacked off a gable end this week with the view to rendaid/mesh and weber pral on top. the existing render has pulled the front off most of the brickwork and i plan to straighten up the gable with render prior to the rendaid cos it all over the place. I know i have to weaken my render strength with the bricks being s**t and crumbly but what i dont know is the strength off the rendaid/pral as in i dont want my render coat to be weaker than the strength of my top coat, if that makes sense.I was gonna do a 5:1 render coat....Am i over thinking this or is my train of though right.........
Cheers Hombres...................:RpS_thumbup:
 
I had this recently and weber told me to rend aid then ocr (to dub out) then rendaid then ocr. Which I did but was a complete ballache and wish I had just used sbr then ocr then rendaid/ocr.

Anyway for yours i'd go for a 4.1 or 5.1 give it a good amount of time to cure before rendaid.

Weber will probably advise rend aiding the bricks before dubbing out, don;t know what they would suggest dubbing out with i'd call them.
 
FreeD said:
I had this recently and weber told me to rend aid then ocr (to dub out) then rendaid then ocr. Which I did but was a complete ballache and wish I had just used sbr then ocr then rendaid/ocr.

Anyway for yours i'd go for a 4.1 or 5.1 give it a good amount of time to cure before rendaid.

Weber will probably advise rend aiding the bricks before dubbing out, don;t know what they would suggest dubbing out with i'd call them.
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Ive already put an SBR slurry on the brickwork and im assuming as long as i get it reasonably straight the rendaid and mesh should be ok, But think all give em a bell like you said.....cant help thinking weber just want you spend loads of cash unnecessarily.......
 
Yea they always push all there products over traditional tried and tested methods. Reasonably flat and you will be fine m8, just don't want any big pits in it, also u'll use less rend aid which is pricy stuff!

Let us know what they advise you to dub out with, bet its ocr.
 
FreeD said:
Yea they always push all there products over traditional tried and tested methods. Reasonably flat and you will be fine m8, just don't want any big pits in it, also u'll use less rend aid which is pricy stuff!Let us know what they advise you to dub out with, bet its ocr.
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What ratio is OCR ?
 
I hear what your saying mate, so the mesh is to stop cracking from building movement but you still could suffer from cracking just from your rendering.
 
as you guys said above ,manufactures are always wanting you to spend a fortune on there stuff ,it's the name of the game ( making money out of us mugs ) lol
 
when you dub out with your render mix use a good sbr mixed with water at four parts water one sbr and add some fibres use this as your gauging solution for your mix, will reduce cracking/shrinkage loads, leave as long as poss then rendaid and top
Also use a forced action mixer and not your usual cement/concrete mixer
 
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henry said:
I hear what your saying mate, so the mesh is to stop cracking from building movement but you still could suffer from cracking just from your rendering.
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Al be putting fibres in the render im using to straighten the gable up henry so hopefully that will reduce any cracking in that coat and al be hosing it down for 3-5 days so it cures properly before the rendaid and mesh..........:RpS_thumbup:
 
warriorupnorth said:
when you dub out with your render mix use a good sbr mixed with water at four parts water one sbr and add some fibres, will reduce cracking/shrinkage loads, leave as long as poss then rendaid and top
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didnt see ya post before i answered henry's.....will the SBR act as a waterproofer as well cos i was gonna just use rendamix...........:RpS_thumbup:
 
Yes mate it will be a little more forgiving as well with the polymers, i don't use any chems any more to plastercise or waterproof
 
Why the need for rendaid? What does it do?

If the bricks are bad then a dubbing out coat, followed by a scratch coat and top off. A little SBR in each coat and mesh in the scratch if the bricks are real bad.
 
warriorupnorth said:
Yes mate it will be a little more forgiving as well with the polymers, i don't use any chems any more to plastercise or waterproof
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Yeah but you use one of those fancy forced action mixers. Just use sbr in a normal mixer and it will be dead as foooook.
 
Artisan998 said:
do ya mean heavy gear DMc??
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Yeah, unworkable.

In a scratch I put half a bucket of lime, waterproofer about third of pint and sbr (gives it strength).

Don't worry about people saying that lime and waterproofer mixed together makes the wall explode (or something like that). It doesn't.

Use good cement like matercrete and some well graded sand, chuck some river in if you think its too fine and it'll set like bell metal.

You want it nice and creamy, easy to use. If it still isn't creamy chuck a bit of plasticiser in too.

Main thing is not to get too bogged down in chemical this and that, it wont fall off or turn to dust if you use good sand and cement.
 
DannyMac said:
Yeah but you use one of those fancy forced action mixers. Just use sbr in a normal mixer and it will be dead as foooook.
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A forced action mixer isn't owt fancy, most of us use em day in day out, i' sure you posess one, and no real point in using lime if your modifying a mix for the scratch/dub coat
 
No I dont have one, although I'd like one. Lime just makes it much nicer to spread, no harm in it.
 
just when danny Mac said he didnt have a forced air mixer i thought it was something different
u sarky *****............:RpS_cursing:
 
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a forced action mixer is owt that turns the material by a mechanically forced action, unlike a belle type mixer that relies on gravity , as the barrel turns it carries the material to the top of the barrel then falls under its own weight to begin the mixing cycle, as opposed to being forced around a container, thats all basically, but it makes hell of a difference
 
PMSL.........still havent got a clue what the difference is to a normal mixer FA
 
And you'll get a similar effect if you let it mix FOR AGES in yer belle mixer, although it might be a bit p!ssy if you're not careful with the water content :RpS_thumbup:
 
Cheers bubbles.......cant believe warrior didnt say just mix it up with a paddle mixer rather than a belle mixer......he's just too technical........bloody forced air mixer indeed......i find the render goes off faster if you use a paddle mixer
 
I've heard a lot of spreads tell me the paddle mixers (or forced action mixers) can have an effect on the set times if mixed on a hi speed for too long??.....i know with casting plasters the more its mixed the faster it sets...not entirely sure myself to what extent that relates to multi and hardwall tho or opc??...

in my experience i've found over the years its more critical how the mortars gauged as opposed to how its mixed...whereas with lime mortars the mixing being FAR more critical in creating the required thoroughly mixed workable consistency adding as little water as poss (being as this is what contributes largely to shrinkage cracks)....prefer to do it by hand especially for course stuff backing coats.....
 
I done rendering with just sbr and with the paddle mixer but still found the mix soon started to go off and it was hard going.
 
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