Extend 'corner render' for larger windows

ChilliBob

Hey guys,

We've had some new windows put into our summerhouse today, about two breezeblocks worth taller than the previous ones, the render around a corner bead (I think that's the correct term) needs 'extending' so to speak.

I'm pretty sure the proper way to do this would be to knock off the existing corner bead, and render, put a new one in, render this and join it to the other render. However, I suspect this may knock more render off and hey presto I have to have someone redo the beads and re-render the entire lot, just after I've put in nice shiny new aluminium doors and windows - sounds a nightmare.

Bearing in mind this is a summerhouse, and this part is probably decorative, what options do I have myself?

1. Glue something which is almost the right size to the current render (perhaps a bit of wood), and fill over this, using a spirit level to get something roughly straight

2. Just slap some filler on and build it up until it's about level

3. Try to stick something over *both* the existing rendered corner and the gap, then fill the gap? (foam then filler?!) and possibly fill over the 'thing' to keep the 'render look'

Any thoughts much appreciated.

A semi close up




How it looks from a distance


With a level against it - It's about a finger width missing.

FreeBear

The right way of doing it would be to remove the render on both sides of the return, fix a corner bead, and then render over the top. But this assumes you can get a corner bead to give the right thickness of finish. There is also a good chance that you end up with a hairline crack developing where new render meets old.

What I did when I had my windows replaced last year was to cut some strips of wood and wedged them in around the reveal. Using a combination of mortar gun and finger trowels, filled the gap with render and left it to set. After removing the strips of timber, needed to fill a few voids that were present. A light sponging within 24 hours of the first lot of render being applied took care of any joints and blended the new in to the old.

stuart45

When you render a reveal you should fix the straight edges to the main wall first, and then render them. In your case it means you would have to fix it through the render, which is why the reveals used to get done first. For a small area like that you usually just get someone to hold the straight edge in place. Walls used to be rendered inside and out like that. I plastered the inside of my extension like that without using any angle beads.The
You need to rough up the render  below for a key, or use a bit of SBR/cement mix as a bonding agent.
If someone holds the straight edge in place for you, tell them to slide it back along the wall to take it away. 
Put it back in place to float it up.
Here's a few photos of doing reveals without beads.

ChilliBob

Thank you both, for some reason I wasn't given any notification on this so only just seen it by chance. The window fitter mentioned wood and taking it away but I didn't really get it! - Same as you are suggesting both of you..

I thought he meant basically putting a bit of wood in roughly the right size, screwing it in the rendering over it, clearly not. 

In effect are you saying get a straight edge bit of timber, hold against the existing reveal, perhaps even clamping somehow (perhaps almost making a frame within the reveals), full inside this frame..

What I don't get is surely the filler (or render) would either:

A. Stick to the wood
B. Slump when the wood is removed if not held in for long?

Cheers both. 

mi-key

You can fix the wood to the wall using no more nails type stuff. If the wood is nice and smooth the render won't stick to it, and leave it to dry for a decent time and it won't slump when you remove the wood. As long as it hasnt totally set you can use a damp sponge to smooth the new render into the old.

If you are planning on painting it, then the repair shouldn't show up

stuart45

If you've got a piece of 3 or 4 x 1 lying around, tack it to the wall with a couple of masonry nails. Don't drive them right home, unless they are double headed ones. Put it against the wall, not in the reveal.
The reveal only looks about an inch deep, so it won't take much mortar to do it. When it's gone into it's final set pull the nails and push the timber against the wall and slide it along the wall a bit away from the reveal. If you pull it out it some of the edge may come away with it. Even if it does it's easy enough to stick a bit more in.

FreeBear

mi-key said:

You can fix the wood to the wall using no more nails type stuff. If the wood is nice and smooth the render won't stick to it, and leave it to dry for a decent time and it won't slump when you remove the wood. As long as it hasnt totally set you can use a damp sponge to smooth the new render into the old.

About 24 hours should be enough time for the render to set. If it is too hard for a wet sponge, rub it down with a scrap of 3x2 wood. The longer the render is left, the harder it becomes.

Also worth priming the area with some SBR if you can lay your hands on a cup full.

ChilliBob

Okay so I'm still confused (been a long week lol).

So you're saying put a bit of wood, say 4 by 2, on the *face* of the building, exactly in line with the existing corner bead. Then fill up to this - so, the face on the front should be flat, but the reveal could be all over the shop?

For some reason I'd pictured this being against the reveal instead, 

Slide it away from the reveal, after a period I guess. I suppose rather than nailing I could brace it with another bit of wood against a small retaining wall nearby.

In terms of the SBR, I have a tin and a half of peel stop lined up for this - I did put some filler on some cracks on Thursday but it's peeling off - I think it'd be better to put the Peel Stop on  *first* to seal the slightly sandy surface, then the Tourpret will stick to it, hopefully!

stuart45

Not sure if this photo is clear enough. The straight edges are fixed on the main wall to do the reveals. They shouldn't be all over the shop as you are working to the straight edge. 
The reveals have been rendered here.
The 

stuart45

The straight edges have been removed on this one.

stuart45

Once the reveals are done, the straight edges are put into the reveals to form the edges for the main wall.