Creating the look of brick masonry without the cost and earthquake risk.
I decided to use acrylic rather than traditional cement stucco because it is very much lighter and so doesn't need a metal lathe to transfer its weight into the wall structure. Acrylic is applied in a much thinner layer and is naturally lighter so does not need a metal lathe. It also sticks well to the polystyrene surface. It is also somewhat rubbery so does not develop cracks.
The official term is "Textured acrylic finish system" (TAFS).
Make sure the TAFS products used are breathable so that water does not get trapped behind.
These are the two major products that I chose.
First apply the Garrison and then apply the Bastion.
The wall has EPS sheeting on the outside of the ICF. This leaves a uniform flat EPS surface, but with indents where the screws with big washers have been used to hold it on. The positioning of the screws is important to ensure that the screws are under the bricks.
To create the bricks, half inch thick EPS sheet is cut into brick sized rectangles.
In the UK, the usual size of a modern brick is 8-5⁄8 × 2-5⁄8 inches, which with a nominal 3⁄8 inch mortar joint, forms a unit size 9 × 3 inches.
In the In USA modern bricks are usually about 8 × 2 1⁄4 inches, which with a nominal 3⁄8 inch mortar joint, forms a unit size 8-3/8 × 2-5/8 inches.
My choice is to use the UK standard (slightly larger bricks) so my bricks are 8-5/8" x 2-5/8" and are installed on a 9" x 3" grid. Allowing for 1/8" stucco thickness round the edge, that means the EPS brick pieces are 8-3/8" x 2-3/8".
The brick pattern is offset by 4.5". So that means the brick depth is 4-1/8".
Brick look examples
These examples of brick styles are presented with what I consider the best look at the top.
The following has nice mortar color and nicely defined bricks. Possibly the brick color is a bit too pale...
In the following the bricks are a bit too beaten up...
In the following the mortar is a bit too yellowy...
The following has a nice brick color, but the mortar is a bit too flush with the surface. This style would be applicable if not using stick on EPS brick faces.
The following is a bit too multicolored. With different colors you need to be too careful to make the bricks look random...
This one is too pale...
This one is too loud...
The best color for mortar is "standard gray Type S mortar".
My window surround design
One of the nice things that come from applying stucco over a brick contoured surface is that the stucco is well supported and so there is no risk of a sheet of stucco breaking away and falling off the wall.
The following notes relate to straight flat stucco (rather than a simulated brick look).
There are a series of training videos (done by TotalWall) starting at https://www.youtube.com/watch?v=IfVKNK3IO1w
Also look at Dryvit.
To get it to stick well to the EPS and to get the layers to stuck together it is best to use latex stucco. You can make latex stucco by using Latex Concrete Additive instead of water when you mix regular type-s stucco.
Ideally don't add any water, ie just use the Latex Concrete Additive in the same quantity that would have been water (although it can get expensive). The Latex Concrete Additive is already about 75% water.
Another possibility is to buy stucco mix with the latex already added in dry form...
Stone veneer version is only a 50lb bag so cost is twice the unmodified.
Color is expensive because 10oz bottle only does 2 bags. May be best to leave the color natural. The color varies when using color additive depending on quantity.
Probably only the finish coat stucco is white.
Look at EIFS videos
Acrylall BASTION Exterior Texture Coating (Stucco alternative) http://acrylall.com/environmental-edge/
The Garrison covers an average of 135sf per 5gal pail. This is for the 1st coat to lay on the mesh and the 2nd coat to cover the mesh together. The Bastion covers an average of 135sf per 5 gal pail. This is for 2 coats finish.
Dryvit will stick to nearly anything and is a VERY forgiving coating. It is "elastomeric" which means it is not brittle and will withstand major temperature fluctuations. It can be sprayed with a hopper gun or brushed on. Dryvit is a brand name and there are many other similar products used by the stucco industry. The undercoating product known as "browncoat" is actually an excellent foam coating and can be sanded. It gives the foam the hardness that is needed before the Dryvit type products (latex stucco) are applied. Find your local stucco supplier...... Bonsal and Parex are common product names. Your local supplier will carry a complete brand "system" that includes the browncoat and stucco. Google up "Elastomeric Coatings" and you should find a wealth of info. Dryvit is just one of several brands. Browncoat.... which is also known as flex-base. Other national brands that compete with Dryvit and may have local distributor willing to sell to you. You can search their websites for closest distributor. www.parex.com and www.stocorp.com . This site looks good http://www.stocorp.com/index.php/en/200907083/Contractor/contractor/menu-id-3.html Distributors of StoCorp...
Miller Paint Company 13800 Bel-Red Road, Bellevue (425) 289-0096
Evergreen Building Products 11025 117th PL, NE, Kirkland (425) 828-6121 http://www.evergreenbp.com/
If it has more jets then it needs a bigger compressor. Ideally I just want 1 jet, but can use stoppers with the other jets to make a 3 jet into a 1 jet.
My existing sprayer is probably still the best bet.
It is a thin coat so would have to stick on half inch thick polystyrene bricks and then spray everything.
Form EPS details
Things such as window sills, drip edges, and the divider between backfill coated wall and above ground wall. Because in my case the windows are recessed into the wall I can use EPS to form a drip edge above the window rather than needing metal flashing.
There should be a 1/4" gap around the windows. This will later get filled with some closed cell polystyrene backer rod.
You can avoid expansion joints if the stucco length is less than 100 feet and the substrate is totally rigid, eg a concrete wall.
Prepare EPS surface
The wall has two layers of EPS sheeting. One of the things this means is that there will be no visible screws or washers as the top sheet is glued to the inner sheet (that is screwed).
After the EPS sheeting is all in place, the first job is to rasp off any high spots and any excess glue.
Cut fiberglass mesh
Fiberglass mesh is used over, and embedded in, the stucco base coat while the base coat is still wet. Because of the quick drying time you need to have the mesh cut to all the right sizes ahead of time.
Use 4oz mesh (4.5oz is fine).
The mesh is to provide reinforcement for an EPS surface so there is no need for mesh if stuccoing straight onto a concrete surface.
Apply base coat and fiberglass mesh
Use a flat mason's trowel to apply the base coat stucco. While the stucco is still wet for a particular wall section, apply the fiberglass mesh. Use the large flat trowel to push the mesh into the surface of the stucco. If you need to add some additional stucco base over the mesh then do so to cover the dry spots. No dry bits of mesh should be visible. Finally over the surface use a plastic stucco float trowel.
Make good the base coat surface
Using a large flat sanding rasp or block, make sure the stucco cement surface is free from any high spots or burrs.
Add backer rod around windows
Closed cell polystyrene backer rod is forced into the gap around the windows to form a secondary gasket seal. Push it in fully to leave a gap that will be filled with caulking.
Add some caulking sealant over the backer rod. Use some blue painter's making tape to avoid getting it on the face of the window frame.
This is optional. It help seal the wall and helps the finish layer to stick. It is only really needed for a very flat finish coat.
Apply finish stucco coat
The largest aggregate is the thing that sets the thickness of the coat.
Avoid doing it in direct hot sun or it will dry too quickly.
Before the finish coat has dried, use a plastic faced large float to smooth and polish the surface and remove any high spots and trowel marks. Keep the float slightly wet.