Outer Skin

[Big Neil]

Picture a cavity wall build with natural stone on the outside (main wall material and also headers and cills). Obviously in this system the inner and outer work together to form a  structure so you have thick bits of stone with normal mortar in between and the requisite wall ties. 

 

If you've got an ICF and want the same external look, how is it achieve? Obviously the structure is all in the ICF bit of things, so does one still use ties and still build the wall EXACTLY in the same fashion? Are those bits of stone less deep, so say 60mm front to back instead of say 120mm? Are they just stuck on with some sort of compound?

[AliG]

When I looked into ICF this was exactly my question.

 

The ICF companies I spoke to said that you would stick on thin stone slips, but I was not convinced this was the right way to go and it was one of the main reasons for not using ICF.

 

When I have looked at pictures of ICF houses they are mostly rendered right into the window reveals with little detailing, I have seen some with stone clad walls, but not the detailing I was looking for.

 

I would love to know if indeed you can do this with ICF.

[Declan52]

If you are using real stone then you could use the wall ties that you use on a timber frame. These will need drilled in to the concrete.

Or maybe as you build up you could put some expanding metal strips in between the blocks so they stick out 150mm with the rest inside the blocks, maybe 100mm. Once concreted in they won't move. 

When you come to build the stone there will be enough play in the strips to move up and down to account for the different stone sizes.

[Stones]

Years ago, we were looking for something to clad concrete piers to match the boundary stone dyke. After a lot of searching, I came across

 

https://www.fernhillstone.com

 

who could supply stone slips to match. They had quite a wide range IIRC, and fitting was with a cement based adhesive. If fixing directly to ICF, I would have thought the critical element would be the fixing medium.  Might be worth giving them a call?

[Declan52]

32 minutes ago, Stones said:

Years ago, we were looking for something to clad concrete piers to match the boundary stone dyke. After a lot of searching, I came across

 

https://www.fernhillstone.com

 

who could supply stone slips to match. They had quite a wide range IIRC, and fitting was with a cement based adhesive. If fixing directly to ICF, I would have thought the critical element would be the fixing medium.  Might be worth giving them a call?

I looked at them at the time but most of their range was stone effect made from concrete. 

Their are plenty of real stone cladding companies out there. The adhesive for mine was just tile adhesive that you would use in a swimming pool. 

[Big Neil]

does it still look like a "normal" house? I sort of have this preconception, probably from watching the Duckworth's cladding on Coronation Street years back, that cladding rarely looks like the think it is supposed to imitate (in this case full depth  natural limestone). For that matter is it any cheaper than just us having the wall built as normal. The biggest concern really is that it should look the same.

 

Any recommendations for real stone cladding companies?

[Declan52]

I used a company in co Donegal called mcmonagle stone. They do both the cladding type and normal stone.

I only have 2 pics on my phone.

The corners are L shaped so look more like real stone work.

Mine is silver and gold quartzite. I have the same silver quartzite flecks in my dash so when it's sunny they sparkle.

[Russell griffiths]

Have a look at the nudura vids on you tube, lots with real stone on the outside. 

[Big Neil]

Can't find any real stone cladding going onto ICF - at least not for the UK. Any further Ideas?

[vivienz]

I'm using Tier System panel cladding on my build. I'm afraid I don't know about ICF but it will onto timber frame, steel frame and traditional build.

 

Sydenhams are supplying mine at a decent price so it's worth a look. The manufacturer has been very helpful with the QS as well. I will post details later  - a bit tricky from my phone.

[Declan52]

If you really want stone cladding then would the simplest option be just to use a cement type board and attach this to the outside. This will give you a surface that the adhesive will stick to.

They aren't cheap and easy to man handle due to their weight though.

[Alexphd1]

We are using a 140mm and 40mm deep sandstone on a mix of concrete blocks and nudara ICF. I dont see a problem with doing around windows etc .

[ConorB]

On 03/10/2018 at 12:48, Declan52 said:

If you really want stone cladding then would the simplest option be just to use a cement type board and attach this to the outside. This will give you a surface that the adhesive will stick to.

They aren't cheap and easy to man handle due to their weight though.

Hi Paddy,

 

I'm wanting to apply real stone veneer onto my ICF. I've sort of come to the same conclusion here that the best method might be to screw cement board direct to ICF webs with a vapour control membrane in between. Then apply adhesive to stick 1.5" stone slips to the board. The stone is around 80kg/m2. Most of the stone companies will only stand over the manufactured stone (<25kg/m2) sticking direct to ICF. 

 

Do you anyone who's gone with this approach and had success or otherwise? Any other ideas for attaching real stone slips to ICF? 

 

Any thoughts from anybody appreciated. 

[JohnMo]

Woodcrete ICF, used exterior quality tile cement and real stone slips direct to the ICF. Photos were taken a couple of years apart.

 

[Russell griffiths]

 

im doing this, Cotswold stone cut down to form a stone slip. 

[ChrisJ]

Natural Stone for an ICF house is no different then conventional masonry, you can use a Brick Ledge (4.5" sculpted ICF form) form at the bottom to carry the stone, usually placed 150mm above finish grade or use an ICF form 4" wider (i.e. 10" below grade to 150mm above then switch to 6" ICF) the Brick Ledge form with proper rebar stirrups is designed to carry 27' (roughly 8.5m) of standard masonry bricks, I don't know that weight value but if you get that and your stone weight you can sort how high the stone can go

 

There are ways to allow you to go higher, I've done 6 storey buildings all masonry and we used an angle iron every 2nd floor to help break the weight load to the brick ledge form at the bottom

 

Brick Ties can be screwed directly into the ICF webs, most are rated for 450lb pull out depending on the screw fastener used (Sorry don't know the metric conversion for that). There is a 2 part brick tie that you embed part of it prior to placing concrete, it goes thru the polystyrene into the concrete void, probably have to import from North America and if I recall fairly expensive and not sure how well it would work since natural stone is various sizes. I did do a project in Los Gatos, California almost 20 years ago and the owner had very thick tie wire (think what was used for T-bar ceilings) cut in 800mm lengths, folded in half and then pushed though the foam into the cavity prior to concrete placement, this was engineer designed for the stone facade which exceeded 30' (9m+) in many areas

 

 

[WiltshireLink]

23 hours ago, Russell griffiths said:

 

im doing this, Cotswold stone cut down to form a stone slip. 

Did you use a carrier board? How much stone have you had to cut!? How did you go about cutting it? Ta

[Russell griffiths]

12 hours ago, WiltshireLink said:

Did you use a carrier board? How much stone have you had to cut!? How did you go about cutting it? Ta

No carrier board, waterproof render with mesh on the icf. 
exterior slip adhesive on the back of the stone onto the render, with stainless steel ties into the plastic webs. 
I cut the stone in half so only needed to buy half as much. 
 

if you can do this job yourself then all good, if you need to pay for it, it will be too expensive. 
you would need to go for one of the tile products. 
as labour will make the cost horrendous, I spent 5 days just cutting the stone down, clipper petrol brick saw. 

[FM2015]

No one seems to have mentioned cavity layer.  Nhbc and labc insist on cavity drainage behind brick and stone fascias.  Not sure if it applies to slips.

 

Stone, 100mm on the bed, with ties to webs at appropriate spacings.

 

Nearly everything we have ever done has had some stone faced element.

Icf brickledge isn't required but it can simplify things.  It can also complicate them.

[ConorB]

On 28/02/2024 at 20:16, JohnMo said:

Woodcrete ICF, used exterior quality tile cement and real stone slips direct to the ICF. Photos were taken a couple of years apart.

 

Any idea how thick that stone was or what weight it had per m2? 

[ConorB]

On 03/03/2024 at 11:45, FM2015 said:

No one seems to have mentioned cavity layer.  Nhbc and labc insist on cavity drainage behind brick and stone fascias.  Not sure if it applies to slips.

 

Stone, 100mm on the bed, with ties to webs at appropriate spacings.

 

Nearly everything we have ever done has had some stone faced element.

Icf brickledge isn't required but it can simplify things.  It can also complicate them.

Suppose the slip adhesive acts as water barrier in that system whereas standard building stone mortar is not technically a barrier. Eitherways, Any moisture would have to make its way through outer ICF plus 150mm concrete plus another 150mm inner ICF to cause any damage. 

Will probably still use a concrete board for peace of mind. The limestone slips I want to use are chunky enough so think it's best solution. Working out around €16 per sqm to buy plus fixings. 

[JohnMo]

8 hours ago, ConorB said:

Any idea how thick that stone was or what weight it had per m2? 

About 40 to 50mm thick, weight no idea per m2