fixing render boards(external)

[Homer]

i think your getting confused mate, you dont put building paper behind the mesh ,

thats what i thought
but a doggy plasterer : told me you put it behing all the mesh so the external finish will not crack if the back ground is likly to move :-\

 

[simplybesty]

I think he was talking about EML mesh . not the mesh you would use on thincoat or mono. The mesh i am talking about is like a heavy duty scrim in 50 x 1 m rolls and you bed it into the material.

 

[Homer]

thanks

 

[plasterjfe]

i am working on a render onto board spec at the mo (remember different systems allow for slight differences in detail depending on their own testing and how much gear they want to sell)

there is no real rule for size of board gaps on my spec but they cant be to big otherwise the mud has nothing to grab and will fall away when dry. we are trying not to exceed 3mm.
It is a must that all joints are coated and detail meshed first and then overmeshed again with the full pass of mesh & basecoat so every joint or abutted edge is covered twice minimium. all systems have differences thats why this work should be left to experienced applicators that have experience in the systems, so many chancers round our way now doing stuff on the cheap or going in blind without realising the ammount of prep that goes into a good job. EWI and thin coats already have a bad name among some specifiers

 

[studentuser]

I'm a complete noob in this area but is the mesh not also there to counter the shrinkage of the render itself?

 

[goody]

Anybody scrimmed the joints first with extra wide self adhesive scrim then full mesh? Sometimes meshing the joints with adhesive first can leave a grid effect when the sun shines across it. On a similar note then why don't you have to scrim up insulation before mesh...?

 

[gooner59]

you tell me paul.

I have the marmorit spec here and thats what hey have asked me to do on the cem board job i am doing.

also i think you can just use the ordinary mesh cut into strips to cover the joint snd no mesh on the cem board itsself

I agree if you create an expansion joint/gap you would need to fill it with an expanding material foam/silicone or something like this ! and this would push the price -up !! hence no proper filling !LOL