Window reveal bead

[Mr Blobby]

Finally, finally we will be getting the house rendered in the next few weeks.  If it stops raining before we run out of time this year.

 

Build is block cavity, alu-clad windows in check reveals.  In the reveal between window and check is the vertical DPC.  Most windows are tight at the front against the check reveal but some have up to 5mm gap.  I am told by the builder that reveals will be rendered to window frame and hence this gap will be fixed.  Which leaves me naturally concerned that this is crap weatherproofing as render and frame will  obviously crack.  When I asked about using a bead against the window he said its not needed.

 

A very long time ago @Iceverge helpfully suggested a window reveal bead to provide a more durable seal between render and window frame.  Like this:

 

 

.. which I like the look of very much.  My builder is, however, going to roll his eyes when I suggest this.  Why on earth would I need to use a bead here anyway, when there's vertical DPC, right?

 

So, just to confirm, can a stop bead like this be used at the window/reveal junction and is it a good idea?  This product seems to be marketed at EWI applications, which my house is not.

 

If this is the best way to do it (my builder prefers to do things the quickest and cheapest way unless I intervene) then is the image above of the right product?  And what about the vertical dpc in the way?

 

What colour bead? White to match the render I guess.  Or grey to match the window frames?

 

 

Edited Monday at 12:17 by Mr Blobby

[Mr Punter]

Can you speak to the plasterer and see what they like to use?  I thought you would just have angle beads and maybe mastic where the render meets the ali frame.

[Mr Blobby]

35 minutes ago, Mr Punter said:

I thought you would just have angle beads and maybe mastic where the render meets the ali frame.

I'll check with the render guy but talking to trades on site the only way it's done here is to render up to the vertical dpc against the window frame and then trim the dpc after rendering.  No bead at the window frame. 

Silicon in the crack later if you want.  The vertical dpc, I'm told, will stop water ingress so why would I want to change it?

No concern for wind blowing into the cavity because air tight tape inside 🤷

Edited Monday at 13:12 by Mr Blobby

[Nickfromwales]

There’s going to be movement, so I’d rather manage it and ensure it doesn’t then migrate further out, at a weak point in that complex bead.

 

If you do as he says, and stop the render at the frame, then all you need is a decent “mastic man” to put the flexible seal at that point to allow the movement to happen behind it.

 

Somethings gotta give, and you’re trying to remove the ‘give’. 

[nod]

It is needed It also makes it much easier for the renderer 

Mesh first then bead on top unlike the photo 

[Nick Laslett]

@Mr Blobby, talked about it in this thread. A couple of us used this product. 
 

This link is in the thread above, to a blog with video discussing the render reveal bead. 
 

https://www.beconstructiveltd.com/why-use-external-wall-insulation-reveal-bead/

[Mr Blobby]

Thanks all.  Stop beads look neater and make sense to me.

 

This afternoon the joiners on site gave me that look (the rolling eyes shaky head look) when I asked about using a stop bead at the window frame/reveal junction.  Said they'd never seen anything like it and the vertical DPC is there to keep it weatherproof and nothing else is needed.  I can see this is going to be an impossible task to convince anyone that there is a another way of finshing the render at the reveal 🙄

 

Just to be clear, our windows are aluclad upvc, not aluclad timber.  Our walls are block cavity, to be rendered, no EWI. Is stop bead still relevant? On line examples look to be for EWI.

 

[nod]

11 hours ago, Mr Blobby said:

Thanks all.  Stop beads look neater and make sense to me.

 

This afternoon the joiners on site gave me that look (the rolling eyes shaky head look) when I asked about using a stop bead at the window frame/reveal junction.  Said they'd never seen anything like it and the vertical DPC is there to keep it weatherproof and nothing else is needed.  I can see this is going to be an impossible task to convince anyone that there is a another way of finshing the render at the reveal 🙄

 

Just to be clear, our windows are aluclad upvc, not aluclad timber.  Our walls are block cavity, to be rendered, no EWI. Is stop bead still relevant? On line examples look to be for EWI.

 

I run a render company and would never run the render directly against a ally window 

Joiners or builders for that matter wouldn’t really know 

If you contact K or Webber or who ever is supplying your render They will all spec a stop bead where the render meets another material 

[dpmiller]

42 minutes ago, nod said:

would never run the render directly against a ally window

that's the point, we *don't* put the render against the window, we already have the upright DPC there as a barrier...

 

edit: and remember also it's a check reveal so there's less exposed frame to work to

Edited yesterday at 06:01 by dpmiller