Render Needed for Dome. Suggestions Please?

[wood fired dan]

After trying to use the 5:1 firelite to GP mix on the weekend I've decided I need something better as its nearly impossible to put on the steep areas of the dome and its extremely crumbly. I'm sure its ok for flat slabs though.
I'm after a sticky render to is suitable for the external rendering of the dome.

I have read that just using sand and cement is a good choice. Does anyone have any comments about this mix?

Cheers

[Les]

Re: Render Needed for Dome. Suggestions Please?

Are you putting this on over insulation or are you trying to use it as insulation?

[wood fired dan]

Re: Render Needed for Dome. Suggestions Please?

Its going over two insulation blankets (total 50mm) so I don't need it to act as insulation.

[Les]

Re: Render Needed for Dome. Suggestions Please?

I would wrap it with chicken wire and apply stucco. I added some vermiculite(more insulation) on top of the blankets so I made some forms out of rebar to make it a little easier.

[david s]

Re: Render Needed for Dome. Suggestions Please?

After trying to use the 5:1 firelite to GP mix on the weekend I've decided I need something better as its nearly impossible to put on the steep areas of the dome and its extremely crumbly. I'm sure its ok for flat slabs though.
I'm after a sticky render to is suitable for the external rendering of the dome.

I have read that just using sand and cement is a good choice. Does anyone have any comments about this mix?

Cheers

I use 5:5:1 medium vermiculite,medium perlite, GP cement. For some reason the 1/2 vermiculite 1/2 perlite works better than using either of them alone. Maybe your vermiculite is too course, it does not stick too well. I take a handful and starting from the bottom build it up using one hand on the outside and the other on top to make a flat ledge. Make it about an inch and a half thick. If you press and hold for a couple of seconds this also helps. The ledge you make will be what you build the next row on top of. The more the dome leans I the easier it becomes. Adding more cement in an effort to make it stickier will simply result in reducing its insulation value. You will swear that the stuff won't work, but given 24hrs it is firm enough. I like to leave it for a week to allow it to lose plenty of its moisture and then do a second layer.by tapping this second layer with the flat of a trowel you can get a really even surface.

For the render layer a 4:1:1 mix works well ie sand, cement,lime

[mrchipster]

Re: Render Needed for Dome. Suggestions Please?

Its going over two insulation blankets (total 50mm) so I don't need it to act as insulation.

Quikwall is a fiber reinforced concrete that trowels nicely, goes straight up no problem and is very sticky. Used to line pools and is totally waterproof when used with latex additive.

It is a little pricy at 12 per 50 lb bag.

Chip