Installing the foam for a one coat stucco system is probably one of the easiest things to do, as far as lath in general is concerned. Roofing nails are used to fasten the foam to the wall but only about 4-6 are needed per piece of 4’x8′ foam.
Foam comes in 2’x8′ sheets or 4’x8′ sheets, just for reference, I am using 4’x8′ sheets in this example but both are installed the exact same way.
- Wire cutting snips
- Tape measure
- Foam knife
- Nails (1 1/2″ roofing will work)
- Pencil or pen (Sharpie)
Installing The First Run:
The first row of foam is going to start right at the bottom and should sit right on top of the weep screed, with the groove side down and the tongue side up. The foam will also have vertical lines on the backside that should face the black stucco paper, these are to allow water to drain.
The first thing to do is find a corner and line up the edge of the foam (4′ side) with the outside of the corner.
Whether you’re starting on an inside or outside corner, you need to make sure that the seam of the foam is in the middle of a stud.
You can simply measure the distance from your starting point to the center of the stud and carry that over to the foam, snap a line (with a chalkbox or straightedge) and cut the foam using a razor with a longer blade (2″ or longer).
Make sure the bottom of the foam is riding inside the weep screed track and straight with the bottom edge of the weep.
Make sure the bottom of the foam is riding inside the weep screed track and straight with the bottom edge of the weep. Then place a couple of nails in the top to hold it in place for now.
Now you can just continue on down the wall butting the vertical joints together while making sure that the bottom edge is inside the weep and straight as you go. Keep doing this for the entire length of the wall and measure the last piece because you may have to cut it.
You will want to tape the vertical joints as you go or you can do it after you have installed all of the foam on the entire building, it just needs to be done. This is just a simple brown tape that is fairly inexpensive and really just holds the seams in place a little better, nothing fancy.
The last step is to carry down the stud marks on the paper on to the foam, so we can use them when it comes time to staple off the wire.
Installing The Remaining Foam:
The foam has a tongue on one side and a groove on the other and are made to slide into one another. These make up the horizontal seams on a foam wall.
The Tongue And Groove Parts Of The Foam: The tongue and groove are on opposite ends of the foam that make up the horizontal joints. They fit together snug and form one solid piece of foam. These will be taped in this example, which I recommend because the rolls of tape are quite cheap and it’s quick and easy to do.
When hanging a sheet above another sheet, make sure the tongue and groove are in place and slide the foam down the wall until it is splitting the bottom seam by 4′, making sure that both ends of the new piece are centered on studs.
Once you have the first sheet staggered, in place and tacked on with a couple of nails then you can continue down the wall with full sheets. You will have to measure and cut the foam sheets that remain on the ends so they fit.
Now you can tape all of the horizontal seams, like we did for the vertical ones.
The last step is to mark the studs on the foam that are on the paper so we know where they are when it comes time to staple off the wire.
The outside corners are fairly easy to do but a couple of key tricks will make it easier to make them straight, which is essential for a professional looking stucco job.
The first thing to do is to line up THE FACTORY EDGE of the foam with the edge of the corner. The factory edge is straight and cut with a machine so it is very straight, we will use this to our advantage.
We will now cut the foam for our other side, making sure it will end on a stud’s center and make sure that the FACTORY EDGE is along the outside corner to keep it all straight and plumb.
Now just tape the vertical and horizontal joints on the edges of your foam and you’re done! Remember to carry your stud marks down and transfer them to the foam for the wire.
These are pretty self explanatory but I wanted to show the basic steps so I didn’t leave anything out and covered all the bases I could.
Pick a wall to start on (it doesn’t make any difference which one) and start by butting the foam into the wall and making sure it will end on a stud. Tape your joints before putting the next pieces on because you will cover a small portion of the piece with the other piece of foam.
Then put the adjacent piece of foam on the other wall and butt it into the foam that we installed previously.
Now you will have to tape the vertical seam that is left on the foam board. Don’t forget to mark your studs on your foam for stapling later on.