Finishing render

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steve1976

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How do the most of you finish your rendering? i was always taught to float up then sponge never had much trouble with this but recently watching a guy on the tv giving it a floating then a run with the finishing trowel to give a sheen look have to say it looked good! anybody else use this method?
 
I agree with the warrior , its what the customer asks for , they normally have a idea of a finnish.Have seen some trowel finnished render , and if its not perfect it can look a litttle shitye.
 
On no account should you finish plain face rendering with a trowel. Whilst it looks good green believe me it looks s**t when dried out, the water doesn't disperse and it ends up cracking. Trick with external rendering is the mix, 6 parts sand to one part cement and one part lime in equal measures. This rubs up real nice and a damp sponge at the end exposes the sand and it will stand the test of time without paint turning that lovely yellow. The best sand (in London) comes from Westerham in Kent though this has become quite soft recently, most washed rendering sand comes from Leighton Buzzard and this will do fine. Always brush down and hose the wall, scratch coat to take out the suction and rule off and float up as normal. With the lime in the mix it sticks real nice to a feather edge/Darby. Also the lime sets by mixing with the air as it dries out, therefore the longer it is there the stronger it becomes and it moves with the seasons like the rest of the building. With a lime mix you have a overcoat protection, that will absorb the rain and dry out again immediately whilst a waterproof render is like a anorak, the water runs off but the house is sweaty inside. Also using a stronger cement rich waterproof render will pull the brickwork to bits causing massive cracks due to being out of kilter with the buildings natural movement, the water gets in these cracks and due to the waterproofer is unable to get out. Sounds wierd but waterproof render is one of the main causes of damp.
 
So you never use any waterproofer at all.Must admit , i was always taught to put in the scratch coat , but agree the 6.1.1 mix is the best for topping off.We use a local quarry sand round here called Frith end sand .Really good gear .
 
Only ever finished opc smooth renders with a sponge, did the guy on tv give a reason why he'd troweled it?
 
No, there are many times I would use waterproofer, On thermalite blocks for instance but not for floating off. Also when pebbledashing. Trouble with waterproofer is it's at odds with all the enhanced cements, and most dust is now enhanced. It has a plasticiser in it that entrains air in the mix and the waterproofer is generally silicon based designed to plug the pores, first coat goes on, just about but the second coat just falls off. So you have to insist on good old fashioned OPC. Truth is mate, if I'm on a job and a builder says use waterproofer or some tosspot architect has specified it I aint going to disagree, but I always explain to them why it is s**t, AFTER I have been paid. I was looking at some sika rendering I did 15 years ago (cant miss it, it is on a gable wall in a main street) recently and it aint stood up well at all, large sections have blown and it is crazed all over, meanwhiles the rendering on the colosseum in Rome is stuck like s**t to a blanket 2000 years on. Reckon they knew what they were on about.
 
He never did church , he was rendering a porch in front of a house and was showing beading round door and windows .dripbeads on the bellcast then scratched it left for 1 day then top coat, float with poly float then run a finishing trowel over it. he seemed to know what he was talking about.
 
Strange one Steve1976 i must say, the difference after troweling it cosmetically cant change the render that much especially if its going to be painted , perhaps the porch was single skinned and his concern was one of water penetration who knows.
 
Could of been lad . as i say it looked good but when it dries out could be a different story your bound to see trowel marks! ron do you not bother with plasticier on top coat then just shovel of lime in the mix better job you reckon?
 
Little bit of plasticer in a lime mix sure does make it spread easy, no more than half a capfull though, failing that tiniest drop of, yip, you got it washing up liquid! Why break your arms eh?
 
Come on Ron if your fishing with fairy, youve got to do better than that to get a bite..... :D
 
f**k me thought it was a simple qeustion, have i seen this done before,yes, have i been asked t o do this befoe yes, yes , i could go into a whole four F*****g pages of the pros and cons , but no i just answerd the question , it's not something i normaly do unless requested ( wooden float, sorry vynel and sponge is normal) but i have been asked a number of times in my 25 years to finish with steel by agents etc, question answerd ??? and yes it it is purely cosmetic in y opinion, so please dont F*****g go on and on and on about it he got his asnwer
 
steve 1976 yes mate you can use a steel trowel to finnish but a bit different,next time you got a bit of s&c up try this but be warned if the works not straight itll look s**t,scratch ,float and fine down as per,sponge if you like,let it tighten up some more,then get your perma shape out prolly the only time youll use it on render,then float it again,thats float it not trowel mind like you would with a plastc float no edge an lightly ,try it an you might be surprised,but its a bit long winded.
 
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