do you know about scrim/mesh ?

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gooner59

gooner59

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years ago if you were skimming plasterboard we would use two different sorts of scrim 1) HESSIAN real thick sack cloth stuff, it had the holes in but it was a much thicker material, & 2) cotton skrim much the same as you guys use now but without the self-adhisive side ,in essence just plain cotton scrim , well the first job was to cut them to length dry ,then to bed/fix the scrim to the plasterboard joints ,we would have say 1/4 of a bucket of skim mixed a bit stiff then ,butter the joints about 2ins (5cm) wide right through then trowel the scrim into this bed,.
Now what i don't get is with EWI systems is it's the same, you apply the coat ,then bed the mesh under the surface !!,. Or you are at fault if say you were to hold the mesh against the insulation then coat as the mesh would be under the coat but against the insulation ,.
now going back to the scrim you guys use now !! this is stuck against the plasterboard then skimmed over ,. so why is this not a bad practice as well ????.
I THOUGHT THE HOLES IN THE MESH/SCRIMM WERE TO LET THE MATERIAL GET A GOOD BOND TO THE SUB STRAIGHT SO WHAT DOES IT MATTER ?? thanks for replies lads !!
 
Having never done EWI not the best to comment... But with scrim it sticks like **** ! Trying to pull scrim out of a joint that has been skimming is not easy task..
 
essexandy said:
And how often do you see a screeder put a layer of screed over the floor before he lays the chicken wire? I've never seen it done, not ever.
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I always done it myself too, but I do not screed anymore.fibres replacing chicken wire, some idiots put it on the floor...I have seen it done lots of times too by old school guys.
 
Never used ewi gooner but get your point totally cos i still think duped scrim was better than joint tape although it don't stop me using tape cos it's quiker and easier. one question though dose the substrate for ewi go on the same as plasterboards ie with a slight gap betwwen the boards cos if i remember rightly from my disatnt (very distant ) college days when the plaster enters the gap and theoretically ouses through similar to lath's this also plays as much of a role in preventing cracks as the scrim or tape.
 
as regards floor screeds the chicken wire, or D49, must be in the screed it is no good what so ever at the base.

ewi scrim is laid into the base coat, you turn the roll over so that it lays against the wall not peeling away.
the way we apply the scrim, the person cutting the scrim pushes it into place with his gloved hand, the second operative follows up with a trowel to bed the scrim in and take off excess material
 
I'm sure it would work fine mesh 1st but it would be a pain in the arse to do unless they made the mesh sticky which would then make it much more expensive. With wind and weather too it would need to be ultra sticky which would mean it would be hard work. Bedding the mesh into the adhesive is a much easier way and also helps flatten the walls out a bit if they're out of shape.
 
malc said:
as regards floor screeds the chicken wire, or D49, must be in the screed it is no good what so ever at the base.

ewi scrim is laid into the base coat, you turn the roll over so that it lays against the wall not peeling away.
the way we apply the scrim, the person cutting the scrim pushes it into place with his gloved hand, the second operative follows up with a trowel to bed the scrim in and take off excess material
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Actually that's what I was waiting for someone to say Malc. In truth when chicken wire is laid straight onto to base and the screed tipped onto, shovelled about and then screeded it ends up sat nicely in the floor. How do I know? Well I've seen a few screeds cut into over the years and the mesh is sitting just fine. With D49 I doubt this would be the case due to it's weight.
 
essexandy said:
Actually that's what I was waiting for someone to say Malc. In truth when chicken wire is laid straight onto to base and the screed tipped onto, shovelled about and then screeded it ends up sat nicely in the floor. How do I know? Well I've seen a few screeds cut into over the years and the mesh is sitting just fine. With D49 I doubt this would be the case due to it's weight.
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Crap
 
in ewi you can be applying basic scrim on the upper floors and a very heavy duty scrim on the ground floor to stop the locals from kicking the installation in.
 
How did we end-up talking about screed and chicken wire ,you cant use chicken wire anymore ,it has to be metal mesh !!,i 'am on about the material mesh you bed into the first coat of modified render on insulation panels of houses that are clad in EWI systems lol......
 
gooner59 said:
How did we end-up talking about screed and chicken wire ,you cant use chicken wire anymore ,it has to be metal mesh !!,i 'am on about the material mesh you bed into the first coat of modified render on insulation panels of houses that are clad in EWI systems lol......
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Sorry my fault, tried with an example and is veered, won't mention the bird restrained again ...
 
gooner59 said:
How did we end-up talking about screed and chicken wire ,you cant use chicken wire anymore ,it has to be metal mesh !!,i 'am on about the material mesh you bed into the first coat of modified render on insulation panels of houses that are clad in EWI systems lol......
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To be fair Gooner threads never, well hardly ever stay on subject and you've already asked this in the render section where it should be.
 
essexandy said:
Actually that's what I was waiting for someone to say Malc. In truth when chicken wire is laid straight onto to base and the screed tipped onto, shovelled about and then screeded it ends up sat nicely in the floor. How do I know? Well I've seen a few screeds cut into over the years and the mesh is sitting just fine. With D49 I doubt this would be the case due to it's weight.
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some screeders pull the mesh up with their hands as they lay. i like to pump up a few gauges then lay the pre cut chicken wire to make sure it is in the middle
with D49 on large areas, we lay a scaffold board down the edge, then lay the D49 so that it sits on the scaffold board therefore about a inch and a half into the screed.
for the next area, tie the D49s together and use the scaffold board as the next edge
 
gooner59 said:
How did we end-up talking about screed and chicken wire ,you cant use chicken wire anymore ,it has to be metal mesh !!,i 'am on about the material mesh you bed into the first coat of modified render on insulation panels of houses that are clad in EWI systems lol......
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sorry gooner, i thought that we had covered the scim question. i had moved on to other reinforcements methods
 
with these systems Gooner your looking at sitting the mesh in the top two thirds of the render rather than at its base where it serves no real purpose
 
Yes Warrior i know where it is placed in the layers ,in most systems , but does it have any bearing on the bond between the insulation and the render ? surly the holes in the mash are big enough to allow a bond, ? what is the meshes primary function ( to reinforce ) the render ?
 
The mesh serves dual purposes Gooner it both reinforces the render and spans the joints in the insulation, surely you can see that to have the base coat 100% in contact is better than it only making contact through the holes in the mesh.
 
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