A Southern California spa tucked into the hillside with Catalina Island views while sitting on the sauna bench

Guest post series continues.

Welcome Jeff C. from Southern California.  We will revisit Jeff’s sauna build after completion.  For now, let’s take a look at his project.  Enter Jeff:

For the past year or so we’ve been planning to build an outdoor sauna.  We’re in Southern California rather than the shores of Lake Superior, but Sauna Times caught my attention and gave us some great ideas about what we could do.  Our lot is unique as the backyard consists of a series of terraces that rise up considerably from the street level out front.  You can see the Pacific Ocean and Catalina Island from up there, so we liked the idea of putting the sauna up the hill for both ambiance and to take advantage of the view.  We already have a spa on the hill so the changing room could do double duty for both the spa and the sauna.

To make it work we needed to locate the sauna close to the spa but we didn’t want to sacrifice a lot of flat space that is already in short supply on our lot.  We chose a small terrace located about ten feet beneath the spa that was unused.  It was a good location as far as proximity but we needed to overcome some challenges to make it work.  The three big ones were the slope of the terrace, a height limit on the sauna itself, and construction suitable to the extreme fire hazard zones of the Southern California hills.  Fortunately, we’ve been able to deal with all of them with some improvising and many trips to the local Home Depot.

Dealing with the slope

The chosen location slopes from left to right and from front to back when looking at the front of the sauna structure.  The front right corner is about three to four feet lower than the back left corner.  Another issue was that a concrete drainage culvert started right about where we planned the front of the sauna.  Clearly we were going to need a unique foundation.

We started by digging down the highest spot and installing a short mortar-less retaining wall to help flatten things a bit.  We still had a big slope differential so we installed concrete piers and used posts of various lengths to come up with a post and beam arrangement.  It took seven piers.  We used the pre-cast ones from Home Depot, each encased in two 50 pound bags of Quickrete.  Lugging 700 lbs of Quickrete up that hill was great exercise!

What’s nice about it is you can dump the Quickrete right into the hole, add water then mix it up with a shovel in the hole.  No cement mixer or special equipment needed.  I dumped in one bag and mixed in up, then placed the pre-cast pier on top of it and added the second bag in the hole around it.  Rock solid and cheap at about $20 each.  We don’t have to deal with frost heaving here so we can get away without making them very deep.

We wanted to limit the foundation height to keep the overall sauna height as low profile as possible (more on that in the next section).  Instead of placing the joists on top of the beam we attached them to the side of the beam at the back of the structure using Simpson Strong-Tie hangers.  Toward the front of the structure the lot had sloped down enough that we could place the beam below the joists.  This allowed us to cantilever the “front porch” out several feet from the front of the structure.  This solved the issue with the drainage culvert as it suspended the platform above it.

All in all, a solid and flat foundation on what was once an unusable sliver of land.

Limiting the Structure Height

Since the sauna structure is below the spa on our hillside, we needed to limit the structure height to prevent blocking the view from the spa.  We wanted to ensure those sitting in the spa didn’t have any impingement of the view of the Pacific and Catalina, or have the vista dominated by the sauna building.  This required that the sauna structure rise no more than 8 feet from the highest spot of the ground to the crown of the roof.  That includes the foundation, the walls, and the gable, and it took some unconventional approaches to keep it that short.

As mentioned, we attached the joists to the side of the beam to minimize foundation height.  The next thing we did was to utilize a very soft roof pitch, only a 1 foot 2 inch rise for a 5 foot run.  We can get away with this in Southern California as we don’t have to worry about snow load.  In fact, our house has a virtually identical roof pitch which the sauna structure compliments nicely.

Last off, we made the side walls only 6 feet 4 inches rather than the usual 7 feet.  Then instead of having a typical attic/loft, we gave the sauna a “cathedral” ceiling with a flat section in the middle.  The sauna ceiling starts at 6’4” on the side and rises to 6’10 for the first third.  It’s then level at 6’10” in the middle third, then sloping back down to 6’4” for the final third.  I’m only 5’10” and my wife is shorter so it shouldn’t be cramped at all.  If the Lakers pay us a visit we might be in trouble though.  We used 2 x 6 lumber for the rafters to accommodate R-19 ceiling insulation since we wouldn’t have an “attic” to place any additional insulation.

Making the Structure Fire Resistant

Wildfires are a real threat in the Southern California hills, every few years we have a disaster with dozens of homes burning down.  We’ve had a lot of rain this year so the hill is pretty green now.  However, we get virtually no rain from May through October, and that hill will be tinder dry by the end of Summer. These disasters rarely burn newer developments and they mostly happen in older 1960’s and 1970’s era construction with wood siding and shingles.  Using fire resistant exterior materials is a must for any new construction here.

We’d love to have a real wood sided sauna structure, but it really would be foolish here.  Instead, we’ll use cement fiber cladding.  Our local Lowes stocks Hardi plank, the cost is reasonable and it looks like it will work well.  Not only that, it can be stained and looks surprisingly like real wood when finished.

In addition, rather than lining the soffits with plywood, we’ll use concrete backer board cut to size.  Last off, the roof will be either asphalt shingles or perhaps tile in keeping with the dominant neighborhood architecture.  The spa deck and stairs leading to the sauna are already composite material for the same reason.  The sauna structure itself will have no exposed combustible material except the fascia.  It may not be authentic Finnish construction, but it’s the prudent move in our situation.

Conclusion

Our project has been a bit challenging as the unique nature of our lot and location led us to improvise from Glenn’s basic outdoor sauna plan.  Even with the challenges, it hasn’t been beyond our DIY capabilities and the most basic materials available at Big Orange.  Don’t let unusual terrain be a limitation, be creative, improvise, and use it to your advantage!

We’ll post a follow up article when the sauna is complete.