Plaster vs. F***ing Render

The wall was probably too dry. Or dusty. Sucks the water out and the render falls off. Wet the wall down before you start. To make it really strong or if the surface is crumbly, prime with diluted PVA a few times & mix the render up with the same. (Follow instructions on the PVA container.)

I rendered the inside of a fireplace to take a stove.

It did have a tendency to slump - luckily I have not made it too wet or I would have been in real trouble.

I think you need to keep it slightly towards the dry side of the mix spectrum...

I did prime it with dilute PVA, but just the once. Immediately prior to applying the render I also re-wet it with a plain water spray. I'm guessing it would have been *even* worse if I hadn't!

Ideally you need a gravity deflector from a tool hire shop. Position it according to the instructions and you can have a localised gravity field that makes the vertical wall effectively horizontal. You have to leave it in place until the render has set, which is expensive because the deflectors are usually rated at 4kW. Well worth it though. After the render is hard you can have a bit of fun. Put the cat on the wall and it will totally freak out!

Bill

Thanks for the info, Phil. Well I've been under a misapprehension, then. I always thought render was something you could trowel on as thick as you please. Oh well, it's One Coat plaster for me in future!

Link won't work.

It's probably somewhere near the Electric Sheep of North Wales.

I've always had good results rendering. You were using 1:1:6? or something sloppier? It does tend to disconnect from the wall, the trick is to trowel over it with the trowel at a steep angle. This pushes the render under the edge back to the wall. Repeat a few times & it tends to stay there. I'm not sold on pva, unless the substrate's coming apart. Phil has most likely don e far more rendering than I have though.

NT

That's odd.

Bill

Yep, there's clearly a different technique required here for render; what works for plaster doesn't work for S&C. BTW, I'm using the pre-mixed-just- add-water stuff from BnQ which states it's ideally suited to this application.

A tip I heard, and have not tried: if the stuff won't stick, add some tile adhesive...

Thomas Prufer

Don't use any PVA unless flakey, ruins the suction. Rendering sand is sharp sand that's been sieved fine, add 5% building/soft sand to make it 'sticky' - no worries then. Use a plasticiser to reduce the amount of water needed. Phil.

It must have decided it won't talk to Australians. It says address not found.

I'm sure if the OP googles gravity deflector hire he'll be able to locate the necessary equipment.

Bill

Pva reduces the initial grab, but a few extra sweeps of the towel usually sorts that out. I find it produces a better bond in the end. Trouble is, a surface doesn't have to be visibly flakey to be too porous, so I pva by default

He'll need a reverse polarity one for the southern hemisphere otherwise it will always end up on the floor! ;)

I was expecting a nice funny spoof, not a 404.

Andy