Testing the limits of online self-education

So I'm building a pool. More precisely, I'm building a pool, a deck, supporting retaining walls, storage cupboards, privacy shield, garden beds, and lighting,

I won’t bore you with the detail of how I arrived here, suffice to say it was largely my own doing. I've decided to document the process mainly for my own records, to look back on someday, but also for family and friends to follow; and perhaps for some cathartic release when things are not progressing to plan (which may be more often than not given I have zero construction experience :).

So, first things first:

Location, location, location

The yard where the pool will be built is quite large with no shortage of potential locations, but it was decided early on to keep it close to the residence with easy access from the existing deck.

Given limited everything (money, labor, time), we decided to keep the existing stairs and put the pool on one side of them. But which side? Which orientation? What's the optimum size? The pool base needs to sit on natural earth - how high will the surface be? All good questions and all questions that I'd struggle to answer purely looking at the site.

Being the geek that I am, my first thought is to model. I enjoy modelling. For 3D, although I've used Fusion for widget style products and Blender for fun, I typically come back to SketchUp. Not because it's inherently better (I suspect it's not), but because it’s the tool I'm most comfortable in. As with programming languages, the best tool for the job is generally the one you know how to use well. So SketchUp it is. Professionals would likely reach for Revit or ArchiCAD, but such tools are well beyond what is necessary for a project like this.

Real-world models also allow accurate assessment of factors that would otherwise be challenging. Things like where the sun will be during summer/winter and thus where shadows will fall. If there’s line of sight between neighbors’ decks and people in the pool.

Accurate terrain

I knew early on that a core challenge would be the relatively steep slope of the yard. Getting the terrain right for the modelling was therefore critical. I was lucky enough to have a paper copy of the site plan from the original residence construction with a full set of contour lines. A quick web search revealed how to get this into SketchUp.

So after a quick scan and trace, I managed to generate the following:

Model of terrain

Original site terrain

Now this is the original terrain of the house block, prior to construction of the residence. During construction, the site was cut and filled to create a level area for the house. From the rear of the house to 10 meters or so downhill is fill (i.e filled with the dirt that was dug out from the uphill part of the block to make it level.

As some readers may have encountered, when you dig a hole, the dirt that comes out magically multiplies. You find yourself with a 1 meter deep hole and a 2 meter tall pile of dirt. This is because undisturbed earth has had a long time to settle. We’re talking millions of years. Put something heavy on it, and it's unlikely to move (within reason). Put that same fill back into the hole and it's a very different story. It's exceedingly difficult to pack that dirt back down and is the reason why things like this exist:

Soil roller

Soil roller

Although fill on our site would have been compacted, it is very unlikely to have been compacted sufficiently to form the base for sixty odd thousand kilograms of concrete, steel and pool water. The base of the pool and the footings of the walls that will surround it need to rest on material that will resist their weight without sinking or otherwise moving. This sort of fill is not that.

So the original terrain is a good start. Next we need to add the house and current rear deck:

House with terrain

House with terrain

With the addition of accurate geolocation (for realistic sun position and shadowing), the existing landscaping, plants, fencing, stairs, and some fancy rendering plugins, I produced the following renders of the two potential locations and designs:

Location A

The design here looks quite nice when viewed from outside, but from the pool deck itself, the view is directly towards the neighbours and quite barren. Because there's insufficient space in this position to orient the pool across the yard, it instead extends down the yard requiring it to be at a lower elevation to ensure it sits on undisturbed ground. This leads to a relatively high retaining wall at the rear of the pool, and poor visibility from the house.

Location B

The primary view from the pool deck is towards the forest, with the ocean poking out on the right side. Privacy is improved and the pool doesn’t extend down into your yard as far.

Given the clear advantages, this location was chosen.

Next up, the detailed design.