Green Building Forum - PassivHaus - Block / Brick Slip Wall Buildup

PassivHaus - Block / Brick Slip Wall Buildup

dsewell — Fri, 06 Nov 2015 18:21:54 +0000

Hello,

We are in the process of designing a New Build, hopefully to PassivHaus standards. We have a design which satisfies PHPP using insulated render (approx 260mm EPS externally with a 215 structural block).

We would like to look at incorporate brick slips but we are struggling to find a suitable system (we would like to use non-synthetic bricks to give a more authentic look). Again, the buildup of the wall would be 215 blocks, 250 - 280 EPS/XPS (or a natural equivalent) then slips externally.

Does anybody have any experience of building with slips and significant levels of insulation? Any views on EPS vs XPS, the need for a cavity, method for fixing slips to wall (ideally a grid / purpose panel) and solution for fixing the panel to the inner wall (obviously thermal bridge free if possible)?

I'm sure we are not the first to look into this, so any thoughts / guidance greatly appreciated.

Best

Dean

PassivHaus - Block / Brick Slip Wall Buildup

fostertom — Fri, 06 Nov 2015 19:04:08 +0000

It's an old and honourable, classic skill, to fake it render.

PassivHaus - Block / Brick Slip Wall Buildup

tony — Fri, 06 Nov 2015 22:26:58 +0000

I would recommend using system sheets of insulation on top of your insulation, mechanically fixed with plastic insulation fixings
Use pistol bricks up the corners and into window reveals.

Reckon xps rather than eps, sticking slips on is easy with products like tile cement available, bricks are then pointed,

If it was mine I would go render with yellowish sand and ashlar lines forget the birch slips.

PassivHaus - Block / Brick Slip Wall Buildup

PeterStarck — Sat, 07 Nov 2015 07:51:29 +0000

I used the Wetherby system for the dwarf wall brick slips on my house. Nobody has yet sussed that they are not full size bricks.

http://www.wbs-ltd.co.uk/external-wall-insulation/wetherby-systems/system-finishes/brick-slip-cladding/

PassivHaus - Block / Brick Slip Wall Buildup

fostertom — Sat, 07 Nov 2015 09:44:22 +0000

Pic no 2 and 6 on the Wetherby site are exactly how not to do it - so obviously sheets of wallpaper.

It's incredible that none of the various systems, whether fake render or brick slip, have yet got around to UK brick sizes - both current 75x225 module and trad 3"x9" module are needed.

PassivHaus - Block / Brick Slip Wall Buildup

dsewell — Sat, 07 Nov 2015 13:33:53 +0000

Many thanks for your comments.

I agree with the "wallpaper" comment, some of the slips do look very fake - I guess in some/many cases they are.

We definitely would like to use a system, does anybody know of any such system sheets. And Fostertom thats a very good point re 75x225 slip - does anybody know of a system for UK sizes?

We plan to use thermally broken insulation fixings and we can get some that will work with 260mm insulation, so thats all good.

Re XPS - some solutions we have seen have a cavity between the slip layer and XPS? Is this something that anybody can comment on? We were thinking EPS above DPM and XPS below. Again, any thoughts?

Thanks again. This is such valuable information.

PassivHaus - Block / Brick Slip Wall Buildup

jamesingram — Sat, 07 Nov 2015 14:37:13 +0000

why xps tony ? graphite EPS is going to be a bit cheaper and of similar R value, density isn't that much of an issue for sticking slips on.

PassivHaus - Block / Brick Slip Wall Buildup

PeterStarck — Sat, 07 Nov 2015 15:44:07 +0000

Posted By: fostertomPic no 2 and 6 on the Wetherby site are exactly how not to do it - so obviously sheets of wallpaper.

It's incredible that none of the various systems, whether fake render or brick slip, have yet got around to UK brick sizes - both current 75x225 module and trad 3"x9" module are needed.

Please bear with me because I don't understand what you mean. The slips I have used are 60x210mm which are the same size as the bricks I used on my previous house. The mortar thickness is 12mm in both cases.

PassivHaus - Block / Brick Slip Wall Buildup

dsewell — Sat, 07 Nov 2015 18:13:09 +0000

Sorry, re the point from fostertom we would ideally like to find a system that uses a standard uk brick size (so 215x65 or as near as possible) and will work with 260mm insulation.

PassivHaus - Block / Brick Slip Wall Buildup

tony — Sat, 07 Nov 2015 23:58:51 +0000

James, xps is much led likely to delaminate and there are rotational forces at work. Xps is firmer and more commonly used in brick slips applications. Better with mechanical fixings, possibly not quits so good at clinging to adhesive but clearly works as we don't hear of drink slips falling off.

PassivHaus - Block / Brick Slip Wall Buildup

PeterStarck — Sun, 08 Nov 2015 08:54:15 +0000

Posted By: dsewellSorry, re the point from fostertom we would ideally like to find a system that uses a standard uk brick size (so 215x65 or as near as possible) and will work with 260mm insulation.

I'm sorry but the information Tom is giving regarding Wetherby brick slips is misleading. My measurements were wrong and the slips are standard UK brick size and the thickness of the slips I used is 15mm. The relevant information is in the attached BBA certificate. You can use the complete system of insulation and mesh and slips or you can use just the mesh and slips as I did. The thickness of insulation is not tied to the slip system and different types and thicknesses of insulation can be used.
I have no connection with Wetherby other than to use their system which I found easy to install.

PassivHaus - Block / Brick Slip Wall Buildup

PeterStarck — Sun, 08 Nov 2015 08:55:21 +0000

A picture of my installation.

PassivHaus - Block / Brick Slip Wall Buildup

tony — Sun, 08 Nov 2015 09:14:57 +0000

Does the insulation have ridges? Nice pistol bricks

Module size and brick size and block size are all metric now, bricks approx 215 X 65 and blocks 435 X 215 setting out courses at 75mm and 225.

Old money bricks worked on four to the foot. And block courses at 9"

PassivHaus - Block / Brick Slip Wall Buildup

PeterStarck — Sun, 08 Nov 2015 09:40:57 +0000

Posted By: tonyDoes the insulation have ridges? Nice pistol bricks

My slips are fixed directly to calcium silicate board with the mesh attached to the board. It's the mesh that has the ridges so it can be fixed to any insulation.

PassivHaus - Block / Brick Slip Wall Buildup

dsewell — Sun, 08 Nov 2015 10:16:40 +0000

Many thanks for the BBA Cert and photograph.

I have looked at Wetherby, it looks good. My only real concern with the system is the use of the metal WBS Brick Slip starter track (may not be required) and the steel fixings which will cause a sizeable thermal bridge. I have contacted Weatherby regarding the starter track and use of alternative thermally broken fixings and will report back. Sugject to addressing thermal bridging through the track and fixings it looks like a good option.

PassivHaus - Block / Brick Slip Wall Buildup

fostertom — Sun, 08 Nov 2015 11:13:18 +0000

Looks like Wetherby and UK EWI cos have provided UK 75x225 module slips - good.

I'm pretty sure all the bricks faked in render systems don't do UK size. if anyone knows different, I'd like to know too.

PassivHaus - Block / Brick Slip Wall Buildup

passivhausfan — Wed, 11 Nov 2015 19:05:42 +0000

I like the pistols. Do they have "headers"? It would look much better in a more interesting bond.

PassivHaus - Block / Brick Slip Wall Buildup

PeterStarck — Thu, 12 Nov 2015 08:01:40 +0000

Posted By: passivhausfanI like the pistols. Do they have "headers"? It would look much better in a more interesting bond.

There aren't headers as far as I know, but nothing to stop you cutting them in half, if that's what you want.

PassivHaus - Block / Brick Slip Wall Buildup

tony — Thu, 12 Nov 2015 19:25:27 +0000

Smet have a simple system that uses rugged xps, mechanical fixings, looks expensive but is said to be a dry process.