Priming blockwork

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church

Well-Known Member
Hi , i take it you are talking about high suction lightweight blocks ? The brickies dream and the plasterers nightmare , rather than stop the suction i prefer to control it , you can just wet them in before render starts , but you do get a different suction from the block itself and the blocks mortar joints , so there is a fine line between over and under watering , pva will slow down and even stop the suction but then you might be causing a keying issue for the render so you might have too use a render bonding agent like sbr or rendergrip .
 

essexandy

The Lake Governor
You don't need to do anything to float lightweight blocks with S&C. Use screeds, don't put too much on at a time before ruling off and Bob's your auntie.
 

leefaithfull

Well-Known Member
Is it okay to put pva solution on internal blockwork prior to s/c rendering? Cheers
how did your sand and cement go on the sucky soft thermalites mate ?,,f**k**g nightmare hey,,should of took my advice and used hardwall,,really watery pva the day before and bobs ya uncle,,s&c on soft blockwork is the wrong way round, ur putting a hard sheet on a soft background,,hardwall is light weight and softer,,yes i know its not for high suction tis why i prime with really really watered down pva the day before, or use a primer,,ive seen s&c crack and shatter many many times before
 

leefaithfull

Well-Known Member
just want to add, if you do insist on s&c on sucky thermalites you need to prime blockwork ie sbr slurry, then either stainless sheets screwed on with stainless screws n washers mix being soft n weak 6:1:1 scratch 7:1:1 top coat or prime blockwork 6:1:1 scratch coat with blue mesh pushed into coat then 7:1:1 top coat,,gotta hold back suction and stop it cracking with mesh,,lime will soften sand and cement,,STRONG MAN CARRIES WEAK MAN,,,ITS A PLASTERING MANTRA,,hope this helps for future projects,,no charge have this one as a freebie
 

essexandy

The Lake Governor
just want to add, if you do insist on s&c on sucky thermalites you need to prime blockwork ie sbr slurry, then either stainless sheets screwed on with stainless screws n washers mix being soft n weak 6:1:1 scratch 7:1:1 top coat or prime blockwork 6:1:1 scratch coat with blue mesh pushed into coat then 7:1:1 top coat,,gotta hold back suction and stop it cracking with mesh,,lime will soften sand and cement,,STRONG MAN CARRIES WEAK MAN,,,ITS A PLASTERING MANTRA,,hope this helps for future projects,,no charge have this one as a freebie
That is quite possibly the most ridiculous post I've read on here in ages.
 

Ritch

Well-Known Member
You don't need to do anything to float lightweight blocks with S&C. Use screeds, don't put too much on at a time before ruling off and Bob's your auntie.
Regardless of putting less on. it sucks the life out of the render, surely a nice wet down and hard wall would be better ?, I hate rendering over thermal light. Give me a solid block any day
 

essexandy

The Lake Governor
Regardless of putting less on. it sucks the life out of the render, surely a nice wet down and hard wall would be better ?, I hate rendering over thermal light. Give me a solid block any day
See I'm the complete opposite, I'd rather float using sand and cement over thermal blocks than use Hardwall or work on dense blocks with little or no suction. I've literally done hundreds of houses of it.
 

church

Well-Known Member
See I'm the complete opposite, I'd rather float using sand and cement over thermal blocks than use Hardwall or work on dense blocks with little or no suction. I've literally done hundreds of houses of it.
So have i , and i can feel every sq meter of it now , dont get me wrong it was easy back then with decent sand and a good labourer , 14 inch mt and a emir float with panel pins , happy days , but im not sure it was all worth it , after all 30 years later same prices on site as back then lol you have to laugh .
 

leefaithfull

Well-Known Member
See I'm the complete opposite, I'd rather float using sand and cement over thermal blocks than use Hardwall or work on dense blocks with little or no suction. I've literally done hundreds of houses of it.
you are putting a hard layer on a soft background , light blocks were invented along with lightweight plaster,get a grip or fall down
 

leefaithfull

Well-Known Member
DSC_0656.JPG
 

leefaithfull

Well-Known Member
took me 3 months on the porch, had to dismantle bricks and mark them , all work done in lime, 30 years ago and go back every year to maintain,,,,i rendered the whole building with a pile of sand and some NHL3.5 ,,,

DSC_0521-EFFECTS.jpg
 

leefaithfull

Well-Known Member
no i get my pet toad to do that,,i use its saliva to stick my beads up with,,,,hold on just a minute,,toad adhesive , tape, beads,,im rocking this voodoo
sorry that was out of order,,your tape thing is a fantastic inovated idea and all power to you sunshine,,the bent nail is for blockwork lines in render
 
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