Sponge Finish

[jammo123]

Hi, iam rendering a wall friday (weather permitting) and was going to float finish it, but i read on another thread that a sponge finish is easier to achieve?

Can someone tell me how to sponge finish my render ? i mean do i use a wet or dry sponge? do i rub it up and down or in a circular motion? basically i have never done a sponge finsh before so i havent a clue !!!

Also do i need to float it before i sponge it or can i sponge straight after i have levelled it off with my feather edge

Thankyou

 

[The-brickie]

The way I do it is to scratch coat, with scars running horizontally, top coat (next day)laid on with a steel trowel level/flatish to the eye, leave for a bit testing every while with a sponge, when ready, (you'll know) circular action rubbing out the trowel marks..

I dont use a feather edge... unless it needs to be really, really flat, i.e. a bathroom.

You can do it early for a rougher finish or later for a smooth finish

 

[jammo123]

cheers mate. Does the sponge have to be dry or wet?

Also do you bother feather edging your scratch coat ?

Cheers

 

[noseall]

cheers mate. Does the sponge have to be dry or wet?

Dry, dry, dry. Bang it on the floor to de clog it too. Keep another sponge handy.

Also do you bother feather edging your scratch coat ?

No. But, if there are any obvious hollows, then these need to be filled.

 

[jammo123]

cheers mate you saved me a lot of work then i was gonna feather the scratch coat !!!!

Can i ask a couple more questions please?

Is it ok to render in the rain? or does it have to be completely dry ?

And also i have an area of painted brickwork that iam going to coat with SBR. Can i coat the rest of the area thats going to be rendered with SBR or will this cause me problems ?

Thanks

 

[Micilin]

cheers mate you saved me a lot of work then i was gonna feather the scratch coat !!!!

Can i ask a couple more questions please?

Is it ok to render in the rain? or does it have to be completely dry ?

And also i have an area of painted brickwork that iam going to coat with SBR. Can i coat the rest of the area thats going to be rendered with SBR or will this cause me problems ?

Thanks

IMHO, you'd be better off ruling off and filling the scratch coat - that's where you do the work to get your wall flat, so that your final coat is an even thickness. This will make it easier to rule off and float and give more uniform drying and setting. If you want it flat when the sun shines along it, rule off every coat. With nice sand and a good edge, you can close it in with the edge to leave miniimum work closing in with float. If youare not bothered about it being flat, that's up to you.

SBR:sand:cement 1:1:1 slurry brushed on to the brickwork ( which has been 'sparrowpicked' with a tackig hammer or claw of a hammer to give a physical key) Put this on a day before you scratch .

Ideally , the whole background will have the same suction - but if it is not practical to slurry a large area just because you have a small area of paint, I would no bother. I would slurry the paint as above, then make sure there is waterproofer in the scratch coat - after a couple of days the waterproofer shoulod give you uniform suction for your float coat.

As an aside, if I was putting quoins, patent reveals or any kind of detail on teh render , I would float the scratch coat before scratching it - not closing it in likea finish, obviously

 

[jammo123]

Cheers mate thats some really helpful advice. Does the SBR have to be applied the day before though? i was hoping to apply the SBR and the Scratch coat on the same day

Cheers

 

[Micilin]

Cheers mate thats some really helpful advice. Does the SBR have to be applied the day before though? i was hoping to apply the SBR and the Scratch coat on the same day

Cheers

It's better the day before ,a s the scratch coat won't slide around on it. If you must. you can do it the same day, just be careful not to mess around with that area too much or it will sag -especially if you need to build it out here. Put that bit on first, ot give it a chance to dry.

best of luck with it.