Monday, October 8, 2012

Building A Well House #7: Prepping For Stucco

Once we got the plumbing and electrical hooked up in the well house
 we were ready to finish up the outside
 and the first step was insulating and wiring for the stucco.

This being a cement block building I wanted to try and refine some techniques
 I have been working on for applying stucco over rigid foam insulation.

Here is the complete series to date for those who may want to follow along:

The first step was to caulk all seams in the building
 where air infiltration could be a problem.

For me it is a loser's game trying to nail insulation onto a block wall
so instead for this small building I used masonry screws to attach 2x2's to each corner...

...and we cut the XPS (extruded polystyrene) foam board to fit between the 2x2s,
holding them firmly in place.

And the corner boards will also act as nailers for the stucco netting 
and diamond lathe.

Since the foam is 2" thick and the 2x2s are nominally 1 1/2" thick
 I added strips of 1/2" plywood to build out to the 2" foam board.

The 2x2s were recycled from pressure treated lumber 
we had removed as part of another project,
 and they have already been used as form boards for the footer and the two bond beams 
 so this is their final resting place.

The small 2x2 blocks set at 16" centers in the corner above 
will act as nailers as you will see below...

...and between them we added scraps of foam.

The square block you can see above is where the wall hydrant will come out
 and will provide a way to attach the hydrant;
otherwise it is very difficult to find anything to screw to.

Above you can see the north wall has been insulated, 
15# asphalt felt (leftover from the roof) has been added, 
and 17 gauge stucco netting with diamond lathe along the edges is in place,
all secured by the 2x2 corner boards.

We ran out of insulation for the east wall so the two walls give a nice contrast,
until we get more insulation to finish.

The black on the east wall above is asphalt emulsion
 for water proofing the below grade areas.

Once the stucco netting was on I applied a 3/4" board for a stop 
and thickness guide for the stucco using those small 2x2 blocks 
you saw a couple photos back as a nailer.

Once we finish the east wall I will complete the corner with another 3/4" board 
and after the stucco is done a trim board will cover the whole thing
 giving a nice finished look.

Corners are a weak point for stucco as the two intersecting planes of flat wall 
will move in opposition to each other causing cracking.

This technique helps to prevent that.

Let's take a look at the whole process again using the west wall (above).

The only difference here is that the rough door frame was installed
 so that it extended out 2" past the block to match the corner revel.

An all weather box (above) for an electrical outlet has been installed and covered with tape,
 and the rigid foam insulation has been put up.

The flat piece of foam on the ground covers the foundation footer
 and will be covered with soil when the final grade is established.

Again the 15# asphalt felt paper, stucco netting, and diamond lathe along the edges 
have been nailed to the corner boards
and the next layer of corner board has been nailed on to the small blocks.

We will use a traditional stucco method of scratch coat (app. 3/8" thick),
brown coat (app. 1/4" thick), and color coat (app. 1/8" thick),
which ends up being a total of 3/4" thick, 
so the corner boards you see above being 3/4" will act as a nice guide.

There are lots of stucco systems available, both cement based and synthetic,
but we decided to stick with what we know best.

This last section of wall above shows the same process...

...except at the bottom I have added a temporary stop for the bottom of the stucco.

Again, the finished grade will come up to this point.

We are just about ready to start mixing our stucco.

Coming up in the next couple of weeks will be posts on 
applying the stucco, the solar Trombe wall, 
and a brief look at the plywood door that you see above.

The whole series to date is: