Before I phone the renderer and make myself look like a complete uneducated tit  can someone explain this materials list he's given me for beads?

 

1 packet of 16-20mm angle beads 

1 packets of 20mm bell casts 

1 packet of 10mm stop beads (for window reveals)

2 15mm expansion beads 

 

(All plastic)

 

So this is standard two coat sand and cement render. 

 

So so is he intending to make the render 15mm but tapering to 10mm in the window reveals and widening to 20mm from the bell cast drip??

I've looked online and there is a bewildering array of types and sizes. 

The angle beads are for corners, I don't think that relates to the render thickness, but how much the bead goes round the corner each way.

 

The 10mm stop beads yes I think that is the render thickness where it stops.

 

The bell cast beads, it's normal for the render to thicken at the bottom to cause the water to drip off away from the wall.

 

The expansion bead, that it the thickness of the expansion gap I believe.

 

This may be of some help

http://www.renderplas.co.uk/corner-beads.php

The angle beads will be used to form all the corners, could be corners of walls or the window reveals. 

The bell casts will be used at the bottom of your wall to form an edge to throw the rain of.

Stop beads are normally used when you change from plaster to another material like timber so will give you a clean straight edge. He could be intending to use them up against the window frame. You can also use them to form arches and corners that aren't 90 degrees.

Expansion joints are used to try and prevent cracking on walls that are likely to settle and move.

I understand the uses ( yes the stops are for the windows ) but it was the varying thicknesses that confused me.

Phone him. Better to look a bit silly on the phone than him turn up and you will look a right plum. 

8 hours ago, Russell griffiths said:

Phone him. Better to look a bit silly on the phone than him turn up and you will look a right plum. 

 

OK, I'll man up