mixing...
- Thread starter carlos
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kirk johnstone
Private Member
Re: mixing
;D
;D
;D
;D
;D
;D
;D
;D
;D
;D
kirk johnstone
Private Member
Re: mixing
dont say it carlos! they fukcing hate it ;D
dont say it carlos! they fukcing hate it ;D
Chris W
Well-Known Member
Re: mixing
what does almost a bag of opc into a mixerful to the brim so its slopping out the lip work out at then? with dry washed jewsons plastering sand, 3/4 of a mcdonalds coffee cup of waterproofer and almost, but not quite, 1 builders bucket of hard water from lincolnshire
what does almost a bag of opc into a mixerful to the brim so its slopping out the lip work out at then? with dry washed jewsons plastering sand, 3/4 of a mcdonalds coffee cup of waterproofer and almost, but not quite, 1 builders bucket of hard water from lincolnshire
carlos
Private Member
Re: mixing
This is it
http://www.restorationuk.com/shop/products/render-plaster-salt-inhibitor-additive.htm
This is it
http://www.restorationuk.com/shop/products/render-plaster-salt-inhibitor-additive.htm
Chris W
Well-Known Member
Re: mixing
if you use less cement but more waterproofer on a damp job is it more likely to be less or more waterproof?
what does actually happen if you put old mix back in the mixer?
if you use a 4:1 scratch coat and a 3:1 float coat which one will fall off first?
what happens if you use soft sand for a scratch coat and sharp sand for a float coat?
what happens if you put render on 30mm thick in one go?
why do damp companies say you shouldnt paint a newly plastered wall with silk paint even though its had 'waterproofer' in it and its been allowed to dry for 3 weeks?
whats the difference between retarder and waterproofer?
whats the difference between waterproofer from jewsons and waterproofer from say, sovereign chemicals or triton?
what happens if you add frostproofer to a mix?
is it possible to skim render the same day?
does render still stay 'green' for a while even if you use orange sand?
if you use less cement but more waterproofer on a damp job is it more likely to be less or more waterproof?
what does actually happen if you put old mix back in the mixer?
if you use a 4:1 scratch coat and a 3:1 float coat which one will fall off first?
what happens if you use soft sand for a scratch coat and sharp sand for a float coat?
what happens if you put render on 30mm thick in one go?
why do damp companies say you shouldnt paint a newly plastered wall with silk paint even though its had 'waterproofer' in it and its been allowed to dry for 3 weeks?
whats the difference between retarder and waterproofer?
whats the difference between waterproofer from jewsons and waterproofer from say, sovereign chemicals or triton?
what happens if you add frostproofer to a mix?
is it possible to skim render the same day?
does render still stay 'green' for a while even if you use orange sand?
Chris W
Well-Known Member
Re: mixing
ive always used 3:1 for damp jobs, and ive always had it on one hit.... dubbed out and straightened it almost straight away...
reason being, in my understanding is that waterproofer acts on the cement content of the mix, which is why its dosed per kg of cement, not per litre of water....
which is also why it doesnt become fully active until the cement has 'cured'...
apparently...
but thats damp jobs... and most damp jobs (or a lot of em anyway) are over old common bricks with lime mortar...
and im also lead to believe that waterproofer breathes slightly, it would have to which is why the damp company waterproofer contains a salt neutraliser, otherwise how would the salt get through if it was completely waterproof?
now theres a loverly little rendering job near me that lloked like it was scratched out @ about 4:1, left for months before floating but it looks like the floating was around a 5/6:1 judging by the colour... its been done over a year now and they still havent painted it... prolly some of the best rendering ive seen for a while...
concrete block before that....
ive always used 3:1 for damp jobs, and ive always had it on one hit.... dubbed out and straightened it almost straight away...
reason being, in my understanding is that waterproofer acts on the cement content of the mix, which is why its dosed per kg of cement, not per litre of water....
which is also why it doesnt become fully active until the cement has 'cured'...
apparently...
but thats damp jobs... and most damp jobs (or a lot of em anyway) are over old common bricks with lime mortar...
and im also lead to believe that waterproofer breathes slightly, it would have to which is why the damp company waterproofer contains a salt neutraliser, otherwise how would the salt get through if it was completely waterproof?
now theres a loverly little rendering job near me that lloked like it was scratched out @ about 4:1, left for months before floating but it looks like the floating was around a 5/6:1 judging by the colour... its been done over a year now and they still havent painted it... prolly some of the best rendering ive seen for a while...
concrete block before that....
kirk johnstone
Private Member
Re: mixing
;D
Chris W said:
;D
kirk johnstone
Private Member
Re: mixing
3-1 SCRATCH
3-1 TOP
if you are skint i sopose you could do a
4-1 scratch
4-1 top
carlos said:
3-1 SCRATCH
3-1 TOP
if you are skint i sopose you could do a
4-1 scratch
4-1 top
kirk johnstone
Private Member
Re: mixing
its not in any way waterproof mate, thats why damp is such a problem.
spunky said:
its not in any way waterproof mate, thats why damp is such a problem.
kirk johnstone
Private Member
Re: mixing
both mate
spongebob said:
both mate
S a plastering
Private Member
Re: mixing
kirk johnstone said:spongebob said:
both mate
kirk johnstone
Private Member
Re: mixing
you know what mate, i dont know? i have never used them. can you put sand and cement on them?
you know what mate, i dont know? i have never used them. can you put sand and cement on them?
Re: mixing
Kirk not having a go mate but if you even considered puting a 3x1 over thermos or faced brick or common brick you will have probs the whole point of rendering is that it should get weaker now a concrete block you may get away with 3x1 maybe but thermos are about 7x1 maybe more .what a lot of guys don't understand is that you can't just throw any old mix on the wall you have to establish what it is your going on to then judge from there .I only say this to help you try make the correct decision before you throw 3x1 in the mixer again not having ago just tryin to help
Kirk not having a go mate but if you even considered puting a 3x1 over thermos or faced brick or common brick you will have probs the whole point of rendering is that it should get weaker now a concrete block you may get away with 3x1 maybe but thermos are about 7x1 maybe more .what a lot of guys don't understand is that you can't just throw any old mix on the wall you have to establish what it is your going on to then judge from there .I only say this to help you try make the correct decision before you throw 3x1 in the mixer again not having ago just tryin to help
kirk johnstone
Private Member
Re: mixing
i can see what you are saying mate and thanks for the concern but i dont concern myself to much with all this the background is to weak or to smooth because i dont rely upon the brick or block alone to bond the render to the wall. i always create a mechanical key in the way that i rake out about one inch in depth of the mortar bed, this way the render is actually grabbing the brickwork and not just floating on top of it. can you see what i am saying mate?
pwi said:
i can see what you are saying mate and thanks for the concern but i dont concern myself to much with all this the background is to weak or to smooth because i dont rely upon the brick or block alone to bond the render to the wall. i always create a mechanical key in the way that i rake out about one inch in depth of the mortar bed, this way the render is actually grabbing the brickwork and not just floating on top of it. can you see what i am saying mate?
Re: mixing
100 percent but that's the joints what if you go over an old week faced brick and your mix is now stronger than the brick its self ,I've gone to see a lot of jobs where clients say the render is f**k*d when you start to chop of there is lumps of brick coming away .and just for interest a thermo block is almost 75 percent air inch depth joints and 3x1 aint going to hold that so somtimes weaker mix does help
100 percent but that's the joints what if you go over an old week faced brick and your mix is now stronger than the brick its self ,I've gone to see a lot of jobs where clients say the render is f**k*d when you start to chop of there is lumps of brick coming away .and just for interest a thermo block is almost 75 percent air inch depth joints and 3x1 aint going to hold that so somtimes weaker mix does help
kirk johnstone
Private Member
Re: mixing
ok erm...
i would say that if the fronts of the bricks are coming off then i dont think anything will stay on it because the background is coming away, i would recommend hacking off as much loose as you can, rake out joints, then if you are still worried you could then consider metal lath
now on the subject of thermolite block, 79% air.. well you cant put air bubbles in your mix so i dont think any mix of sand and cement will be weaker than them, any way i have never seen a house built out of thermolite block, i thought they were for the internal in which case you would use tough coat.
now here is one for everyone to think about seen as how everyone is worried about the back ground being weaker that the plaster sitting on top of it. which is weaker- finish or paper? yes thats right we all skim plasterboard, or what about driwall boardadhesive on top of thermolite block?
now i have got all you 3-1 haters thinking haven't i? ;D
pwi said:
ok erm...
i would say that if the fronts of the bricks are coming off then i dont think anything will stay on it because the background is coming away, i would recommend hacking off as much loose as you can, rake out joints, then if you are still worried you could then consider metal lath
now on the subject of thermolite block, 79% air.. well you cant put air bubbles in your mix so i dont think any mix of sand and cement will be weaker than them, any way i have never seen a house built out of thermolite block, i thought they were for the internal in which case you would use tough coat.
now here is one for everyone to think about seen as how everyone is worried about the back ground being weaker that the plaster sitting on top of it. which is weaker- finish or paper? yes thats right we all skim plasterboard, or what about driwall boardadhesive on top of thermolite block?
now i have got all you 3-1 haters thinking haven't i? ;D
essexandy
The Lake Governor
Re: mixing
Kirk every time you put plasticiser in your mix you are putting air in the sand & cement.
Board adhesive onto blocks doesn't cover the whole wall so it tensile strength won't cause any problems unlike when strong render goes onto soft bricks and causes the problem described by pwi.
I know you've looked at my website Kirk, some of those banded renders are on thermalite/celcon blocks, some not far from me have been done for 15 years now and haven't got a single crack on them, first coat 6:1 topcoat 9:2:1 8)
Kirk every time you put plasticiser in your mix you are putting air in the sand & cement.
Board adhesive onto blocks doesn't cover the whole wall so it tensile strength won't cause any problems unlike when strong render goes onto soft bricks and causes the problem described by pwi.
I know you've looked at my website Kirk, some of those banded renders are on thermalite/celcon blocks, some not far from me have been done for 15 years now and haven't got a single crack on them, first coat 6:1 topcoat 9:2:1 8)
kirk johnstone
Private Member
Re: mixing
well there you go you just proved your self wrong in that you cant a strong mix on a weak background? and its ok mate you can go on about it if you want mate, i take all advice and i appreciate your point, i come on this forum to learn more about the trade i love. i am not set in my ways with the way i mix sand and cement its just it works just fine for me and the way i do it, if i ever get a phonecall to say that the work i have done is falling off then i will reconsider but as i have sain in another post there was a scotch plasterer called w. miller and he used to use this ratio and i some cases an even stronger mix and his work is still there today.
pwi said:
well there you go you just proved your self wrong in that you cant a strong mix on a weak background? and its ok mate you can go on about it if you want mate, i take all advice and i appreciate your point, i come on this forum to learn more about the trade i love. i am not set in my ways with the way i mix sand and cement its just it works just fine for me and the way i do it, if i ever get a phonecall to say that the work i have done is falling off then i will reconsider but as i have sain in another post there was a scotch plasterer called w. miller and he used to use this ratio and i some cases an even stronger mix and his work is still there today.
kirk johnstone
Private Member
Re: mixing
am not saying that they will crack mate all i am saying is that your mix of sand and cement is still stronger than the thermo blocks. do you agree or would you say that your sand and cement mix is weaker than a thermo block?
essexandy said:
am not saying that they will crack mate all i am saying is that your mix of sand and cement is still stronger than the thermo blocks. do you agree or would you say that your sand and cement mix is weaker than a thermo block?
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