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Installing Renderboard


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Hi all, I have a few questions if anyone can help me?

 

1) I am using 25 x 50 battens to attach my renderboard, on the ends of the boards can I use separate battens for each board or should I attach them to the same batten? Separate battens would be far easier but I am worried it may cause problems?

 

2) My SIP installer has told me there will be very little settlement / movement so would it be okay to run battens the full length or do I need to consider leaving gaps between the ground and first floor or anywhere else, is there anywhere I can go to get a plan / design?

 

3) I don’t know how I can finish above windows and doors to leave a ventilation gap to make it look good? Surely it would just be a gap with mesh which doesn’t look great?

 

Thanks!

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1.  You should use the same batten to join the 2 boards.  You may find that 25 x 75 give you a bit more meat.  If you use separate you may get cracking between the sheets.

 

2. The settlement tends to be in the floor zones, as timber shrinks a lot across the grain.  Not so bad with engineered joists but there is still often a 38mm locating plate and top plate, so could be 8mm shrinkage.  If it is only 2 storey you could just go straight over.

 

3. With the windows, run 25 x 50 batten round the perimeter.  Cut the vertical battens for the renderboard short of the opening by 100mm top and bottom so there is no dead zone for ventilation.  There are no gaps in the board.  The ventilation should be from the bottom and out through the top.  Mesh at the bottom and the top, unless it join into the roof vent void.

 

You should fix a fire stop between storeys but this would need to be intumescent so as not to interfere with the ventilation on the rainscreen.  Expensive and it often does not get installed on site.  As it is not Grenfell you don't have too much to worry about.

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Thank you for your advice.

 

This maybe ridiculous but if I used 25 x 50 battens then 25 x 75 to join the boards the 25 x 75 finished size is actually 22mm deep, would this be an issue?

 

I was going to vent the walls out through the roof void, it is a SIP roof and I was planning on 25 x 50 battens with 18mm ply on top before the metal covering, Will 25mm be a big enough space?

 

Is it a requirement to fit fire stops? Is it only between floors or anywhere else? What product is best to use?

 

Thanks,

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29 minutes ago, Ryan Bazeley said:

This maybe ridiculous but if I used 25 x 50 battens then 25 x 75 to join the boards the 25 x 75 finished size is actually 22mm deep, would this be an issue?

 

Yes.  You would need to pack to the same as the other batten.  I would either do all in 75 or all in 50.

 

31 minutes ago, Ryan Bazeley said:

I was going to vent the walls out through the roof void, it is a SIP roof and I was planning on 25 x 50 battens with 18mm ply on top before the metal covering, Will 25mm be a big enough space?

 

Should be but you need to get confirmed.  Often you also need some insulation 30mm? under the SIP roof.

 

33 minutes ago, Ryan Bazeley said:

Is it a requirement to fit fire stops? Is it only between floors or anywhere else? What product is best to use?

 

Probably yes, but does not happen.  I have used Envirograf in the past on 4 storey.  Expensive.

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  • 2 weeks later...

Hi, do you guys have any photos or drawings showing how to finish render board where it meets the soffit to keep a ventilation gap? My roof is standing seam with a metal soffit and I am struggling to know how to finish where these meet without it looking rubbish?

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On 14/06/2021 at 19:30, Mr Punter said:

 

Often a warranty is worthless.

 

Yes and no. If it's issued by the render manufacturer (Weber or Parex) then the installer needs to submit a design, which is approved, and there is some liability if the system fails.

 

You can also fall back on your latent defects policy if there is a materials issue later.

 

If it't not insurance backed or just issued by the installer then yes, likely worthless.

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6 hours ago, Ryan Bazeley said:

Hi, do you guys have any photos or drawings showing how to finish render board where it meets the soffit to keep a ventilation gap? My roof is standing seam with a metal soffit and I am struggling to know how to finish where these meet without it looking rubbish?

 

It you post up a detail someone could help.  If the soffit is vented, you could use this.  You will either take your render up to meet the soffit or render first, then butt the soffit up to this.

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On 14/06/2021 at 18:08, Ryan Bazeley said:

I was going to vent the walls out through the roof void, it is a SIP roof and I was planning on 25 x 50 battens with 18mm ply on top before the metal covering, Will 25mm be a big enough space?

 

No, you need minimum 50mm ventilation gap below the ply supporting a metal roof.

7 hours ago, Ryan Bazeley said:

My roof is standing seam with a metal soffit and I am struggling to know how to finish where these meet without it looking rubbish?

 

Speak to your metal roofing contractor for their recommended detail as there isn't necessarily a need to use soffit vents as you can 'hide' the ventilation behind/below certain overlaps in the roofing/fascia/soffit buildup, or alternatively use verge ventilation instead. All depends on the whole picture.

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