Green Building Forum - EWI Cladding v Silicone render Tue, 14 Apr 2026 10:52:10 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 EWI Cladding v Silicone render https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310258#Comment_310258 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310258#Comment_310258 Sat, 21 Feb 2026 21:37:47 +0000 Victorianeco
While I can appreciate it's quicker and lighter we feel we would possibly like vertical cladding.

I guess that would mean we'd need vertical battens followed by horizontal followed by the cladding...

What are the pros and cons of each? And are there any simpler methods of fixing vertical boards while ensuring drainage?]]> EWI Cladding v Silicone render https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310259#Comment_310259 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310259#Comment_310259 Sun, 22 Feb 2026 11:26:12 +0000 djh
Our lime render, faced with Beeck paint, hasn't shown any signs of growth, FWIW. That's on north, south, east and west facing.

Vertical cladding has the downside that if it starts to decay/rot at the bottom, you have to replace all the cladding. Horizontal cladding you just replace the planks at the bottom.]]> EWI Cladding v Silicone render https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310260#Comment_310260 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310260#Comment_310260 Sun, 22 Feb 2026 16:22:55 +0000 Victorianeco
But my house/project has all 4 elevations

The cladding proposal would be on the south facing elevation ie front of house
Undecided on vertical or horizontal but I think aesthetically vertical would look better.]]> EWI Cladding v Silicone render https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310261#Comment_310261 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310261#Comment_310261 Sun, 22 Feb 2026 16:43:10 +0000 Peter_in_Hungary
If you put cladding on the EWI then this will still need periodic maintenance and you will still need the top coat of adhesive + mesh on the EWI before the cladding (rodent protection) so probably considerably more expensive.

With vertical cladding there is the good chance that water will get into the joins and aid the process of rot whereas with horizontal cladding there is much less chance of water ingress due to the action of gravity.]]> EWI Cladding v Silicone render https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310262#Comment_310262 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310262#Comment_310262 Sun, 22 Feb 2026 17:01:20 +0000 djh
Using a rot-resistant timber is also important for cladding, of course.]]> EWI Cladding v Silicone render https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310263#Comment_310263 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310263#Comment_310263 Sun, 22 Feb 2026 17:13:45 +0000 Peter_in_Hungary Posted By: djhUsing a rot-resistant timber is also important for cladding, of course.
Another name for rot resistant timber is uPVC :bigsmile:]]> EWI Cladding v Silicone render https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310264#Comment_310264 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310264#Comment_310264 Sun, 22 Feb 2026 18:16:30 +0000 Victorianeco
Seems overkill to mesh and coat the EPS. Can you not clad direct through the EPS? Surely cladding systems don't ask need to be ventilated? Just thinking of say Catnic roof cladding, they don't have air gaps they just go over the roofing membrane and screw direct into OSB board.

Couldn't a similar approach be taken with the walls? A thinner system say 11mm OSB screwed through?

We like the Scandinavian style properties, can't seem to find any with silicone render style they all seem to be clad]]> EWI Cladding v Silicone render https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310266#Comment_310266 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310266#Comment_310266 Sun, 22 Feb 2026 19:26:39 +0000 djh Posted By: VictorianecoJust thinking of say Catnic roof cladding, they don't have air gaps they just go over the roofing membrane and screw direct into OSB board.Can't speak for Catnic roofs but our standing seam roof has a 'metal' membrane underneath it, which is like a regular roof membrane but with a polyproplyene mesh over the top to provide an airspace and drainage plane. As you say, the roof is screwed to the ply underneath by hidden fasteners.]]> EWI Cladding v Silicone render https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310267#Comment_310267 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310267#Comment_310267 Sun, 22 Feb 2026 19:51:32 +0000 Victorianeco EWI Cladding v Silicone render https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310269#Comment_310269 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310269#Comment_310269 Sun, 22 Feb 2026 21:06:29 +0000 Jonti EWI Cladding v Silicone render https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310270#Comment_310270 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310270#Comment_310270 Sun, 22 Feb 2026 21:56:45 +0000 Victorianeco EWI Cladding v Silicone render https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310272#Comment_310272 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310272#Comment_310272 Mon, 23 Feb 2026 06:43:59 +0000 Peter_in_Hungary Posted By: VictorianecoSeems overkill to mesh and coat the EPS.
The adhesive coat is to protect the EPS from mice which love to breakfast (and lunch and supper) on EPS. The mesh adds strength to the 3mm thick adhesive]]> EWI Cladding v Silicone render https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310276#Comment_310276 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310276#Comment_310276 Mon, 23 Feb 2026 09:15:07 +0000 djh Posted By: VictorianecoDid you fit it yourself on the roof?Do you mean me? I fitted the roof membrane. Specialist contractors fitted the standing seam roofing.]]> EWI Cladding v Silicone render https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310278#Comment_310278 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310278#Comment_310278 Mon, 23 Feb 2026 09:26:14 +0000 Peter_in_Hungary Posted By: djhI fitted the roof membrane. Specialist contractors fitted the standing seam roofing.
Do you find the standing seam roof noisy in rain or hail ?]]> EWI Cladding v Silicone render https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310279#Comment_310279 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310279#Comment_310279 Mon, 23 Feb 2026 09:30:26 +0000 WillInAberdeen EWI Cladding v Silicone render https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310280#Comment_310280 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310280#Comment_310280 Mon, 23 Feb 2026 10:09:24 +0000 fostertom Posted By: Peter_in_HungaryDo you find the standing seam roof noisy in rain or hail ?or particularly for profiled metal roofing, which isn't flat on a ply surface, but floats free like a drumskin. In my experience, yes it can make din if you hear it through a window above, but underneath is as inaudible as slate, tile etc, given all the layers of structure, insulation, airtightness etc which (at least in GBF-standard construction) we do nowadays. Therefore is fine, in my book.]]> EWI Cladding v Silicone render https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310282#Comment_310282 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18407&Focus=310282#Comment_310282 Mon, 23 Feb 2026 12:20:27 +0000 djh Posted By: Peter_in_Hungary
Posted By: djhI fitted the roof membrane. Specialist contractors fitted the standing seam roofing.

Do you find the standing seam roof noisy in rain or hail ?
Posted By: fostertom
Posted By: Peter_in_HungaryDo you find the standing seam roof noisy in rain or hail ?
or particularly for profiled metal roofing, which isn't flat on a ply surface, but floats free like a drumskin. In my experience, yes it can make din if you hear it through a window above, but underneath is as inaudible as slate, tile etc, given all the layers of structure, insulation, airtightness etc which (at least in GBF-standard construction) we do nowadays. Therefore is fine, in my book.

PiH, no but as Tom says we have the roof structure in between (18 mm ply on top, then 450 mm Warmcel, then Panelvent and plasterboard. Plus two membranes, glulams etc). We don't open windows when it's raining!
We hear helicopters from Wattisham when they fly overhead, but not much else unless we choose to listen for it.
edit: We don't get serious hail in the UK, just kid's stuff.]]>