Fibres in Render. What are they and where to get some?

[wood fired dan]

I've heard that adding fibres to the render it will help strengthen the render. Is this true and if so, what are they called?
I've tried looking on line to find some but its hard when you don't know what your searching for.

Any advice would be helpful.

Cheers

[Tscarborough]

Re: Fibres in Render. What are they and where to get some?

Yes, they help with shrinkage cracks and also provide some additional compressive and flexural strength. Here they are called stucco fibers, they are not glass they are polyester or nylon. For render they should be short, in the range of 1/2" to 3/4" and added at a rate of 1.5# per yard (i.e. a handful per bag of premix stucco), and should be dry mixed with the cementious material before water is added.

[Pompeii Nate]

Re: Fibres in Render. What are they and where to get some?

Please forgive my lack of knowledge here but may I ask where exactly you would be using this fiber? I know you said in the render but I am not totally sure what that means. Thanks in advance!

Nate

[brickie in oz]

Re: Fibres in Render. What are they and where to get some?

Never seen fibres put in render here ever.
I know they used to use horse hair in plaster in the 1920's.

[david s]

Re: Fibres in Render. What are they and where to get some?

Most folk ten to use chicken wire for the reinforcing, but the problem is that it does not conform to a compound curve easily. One way is to put it in place in smaller manageable pieces. If you go the fibre route get some advice from concrete engineering suppliers. The short thin polypropylene fibres give very good compression strengthening but poor tensile strength (so my supplier and data sheet say) I use both the fine fibres and some larger heavier ones which give good tensile strength. The fine fibres don't disperse easily when mixed dry, but they do once water is added. You need to mix for about double the normal time to make the clumps fully disperse. Try the horse hair if you have horses, but there are better modern designed fibres available. There is also Alkaline Resistant glass fibre available for the same purpose. Apparently the alkaline cement/ lime tends to eat the normal glass fires.