rendering over render

[madmick]

I want my whole bungalow re-rendered. I have small patchs of loose render, not many. Walls seam to be sound.
Builder says he will fill in patches then render on top of existing render. Two coats then smooth it over. But i am now worried as i have been told this is bad practice and old render should be removed as the weight of it may pull old render away from walls. And coming to think of it i have always seen workman removing old render before appling new.
If there is any builders,plaster-renderers who can advise me if this is bad practice to render over existing render it would be greatly appreciated

 

[masona]

Providing the old rendering is okay then you shouldn't any problem at all.

My rendering has been re-render over old and not has any problem since 1981.

If you do a search on here, you might be interested to use lime. Some good info on here.

 

[Tony6]

It is always best to remove loose render as there my be over problems that have cause it, ie cracks that have let water in, that have caused it to blow.Have you checked to see if the reder has blown in other places?

If the render is tight / sound ,you MUST key the render before you render over it .Also the new render should not be stronger that the first in mix.

Also the wall must be wetted down with water ,for adhesion or some kind of bonding agent. SBR bonding agent is quite good , This is not a PVA as the SBR will not re-emulsify in damp conditions.

On a personal note my friend had his side wall rendered over, by another builder as i was too busy ,Because he did not KEY it properly the render started to blow and crack.He now has a court case ongoing.

Beware make sure he has a good rep! and you wont have a problem.

 

[mj62mj62]

Hello!

I'm a DIY newbie, thank you in advance for your help and patience.

The house had water coming in, apparently through cracks in the exterior render.

Their fix was to render all of the exterior rather than just to fill the cracks. I don't believe they took the existing render off, but I wasn't there when they did the work either.

They're done now, and our exterior walls are all bumpy instead of the smooth walls they were previously


I'm trying hard to understand, but they basically said that they had no choice to make it bumpy and that it's too risky to remove all the render and re-do it smooth because they don't know if the underlying walls will move.

He spoke for 20 minutes and I still don't get it. Something about smooth would have just cracked anyway - which suggests I did have a choice.

Does this make sense to you? I don't like the bumpy - but obviously I'd choose bumpy and dry over damp and smooth. I just need to know if he's pulling a fast one and trying to get out of the fact that he should have asked me what style I wanted...

Regardless of that, do I have any options for making it smooth? If I now have render on top of other render, "Tony6"'s post above suggests that anything on top of that would a further bad idea... Can bumpy render be sanded down?

Thanks!

 

[masona]

I just need to know if he's pulling a fast one

Me think it's cowboy job any photo?

 

[BREAKALEG]

Sorry to hijack the original post but i have had 3 estimates for pebble-dashing today, all 3 between £2500-£3000 but one company said all the pebbledashing would need to be removed by us.
The other 2 companys said they would hack off blown areas and window reveals and pebble-dash over whats sound, at the moment we have pebble-dash which has been heavily painted and in areas you can push your finger through the paint.
Do you think the scratch coat would bond to a painted surface?

 

[ashymoko]

For any over rendering i always use flexible render, itll adhere to almost any surface and never cracks.

 

[drnail]

is that summat like kielm render ashymoko , if so thats real good stuff imo

 

[ashymoko]

yh keim, or kay render its all pretty much the same stuff, easier to face up, and a nice finish on it as well. not the cheapest of options though, lol.