How To Build a Back Porch aka Hot Water Tank Enclosure aka Tool Shed

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Pam wanted a propane hot water tank installed. A back porch would work as an enclosure and double as a tool shed. How to build such a thing? That should be simple enough–just copy the front porch I built last spring, except make it one foot wider. The front porch is eight feet long, or deep, but only seven feet wide due to space restrictions; the back porch could be a full eight feet square.

We live off grid. The solar hot water system I put together in 2012 works well enough…except that the water in the tank doesn’t get all that warm in midwinter, and it’s necessary to schedule baths and showers during late afternoon to make the most of it. With my wife’s disabilities, she’s been craving the ability to take a hot shower at any time of day or night to soothe her various pains a bit. I couldn’t argue with that, so the project was on.

At first, I’d thought to add an on demand, tankless heater–but those won’t work where the water has been preheated as it often is with the passive solar system. On demand units rely on cold incoming water; if it’s too warm, it thoroughly messes up their sensors.

That left only the standard, old school sort of heater, though I did end up finding one with some helpful features.

Of course, the building addition had to be built before the tank could be installed. Duh.

The back door of the Border Fort, prior to building the back porch.  The addition has to include the door and the incoming hot water piping (black insulation, to the right of the door) while leaving room to see out of both house windows.

The back door of the Border Fort, prior to building the back porch. The addition had to include the door and the incoming hot water piping (black insulation, to the right of the door) while leaving room to see out of both house windows.

As a first step, the ground had to be prepared for the pouring of a concrete pad. This is a little tricky at our place, due to the rock fill that covers the French drain; both those rocks and the adjoining dirt have to be scraped clear or otherwise removed to allow the porch’s footprint to be leveled.

Beginning the ground leveling process.

Beginning the ground leveling process.

The ground only needs to be “approximately” level. Perfection is not necessary due to the fact that I use 2″ x 6″ lumber for the forms but really only need a 4″ pad. There’s a good inch of squiggle room in the depth factor. Professionals would of course sneer at this, but for me, rough and ready (in this case) works just fine.

The 2" x 6" concrete forms are in place.

The 2″ x 6″ concrete forms are in place.

It was time to get a pallet of Maximizer premix concrete delivered from Home Depot, haul the concrete mixer out of the storage shed, and get to pouring. Unfortunately, I forgot the key lesson from the pours I’d done last spring for the front porch and the gazebo bird feeder: With Maximizer, mix it super-soupy or it’ll flash set on you. That’s a big no-no with other “normal” types of concrete, but with Maximizer it’s a must.

As a result of the memory glitch, this porch pad ended up being the worst pour I’ve done to date. The outer edges weren’t bad, but there was a big, ugly, swirly-lumpy dip in the center.

Gross.

On the flip side, the pad–ugly as it was–would do the job I needed it to do. In the area where the hot water tank will be located, the concrete is fairly level. And, as I did with the front porch after being dissatisfied with that pour, I know how to “fix” it later on: Come spring, when the weather is warm enough, I’ll fill in that dip with stucco, then paint the stucco…and no one (other than Pam, me, and the readers of this page) will ever know the difference.

I did this porch pad concrete pour in four hours flat, which was good--except that the pad ended up with a bit of a dip in the middle.

I did this porch pad concrete pour in four hours flat, which was good–except that the pad ended up with a bit of a dip in the middle.

Concrete needs to cure for a week or so before it’s ready for the next step, so we did that, then removed the forms. Now it was time to get going with the carpentry.

After the concrete is given a week to cure, it's time to remove the forms and begin the framing work.

After the concrete is given a week to cure, it’s time to remove the forms and begin the framing work.

Framing begins with the stud walls, erected one by one and braced in position, after which their footer boards are nailed to the concrete. This is done by drilling a 3/16″ hole through the footers and into the concrete (using a masonry bit). Then two 10d nails are hammered into each hole, side by side, which produces a firm bond between wood and concrete.

For the front wall, which uses larger 2″ x 6″ lumber, a 5/16″ bit and 16d nails were used.

The first stud wall is constructed, erected, and braced.

The first stud wall is constructed, erected, and braced.

10d nails hammered into predrilled holes secure wood to concrete.  (16d nails were used on the front wall, which was made of 2" x 6" lumber.)

10d nails hammered into predrilled holes secure wood to concrete. (16d nails were used on the front wall, which was made of 2″ x 6″ lumber.)

The second wall framing was completed by flashlight.

The second wall framing was completed by flashlight.

As readers of our other How To posts may already know, I build according to what makes sense to me. My techniques may look eccentric to others…but they work, and that’s the bottom line.

One of those eccentricities lies in the way I hang doors. Most builders put the house walls together, adding the doors after the rest of the framing is done. I reverse that, standing the pre-hung doors up on the footers of the stud walls with the framing lumber “hung loose” to the sides, secured at the bottoms only–and then pull the side pieces in tight before nailing the top boards in place.

This oddball procedure gives me two advantages:

    1. I don’t have to worry about getting the size wrong when building the doorframe.

    2. There’s no gap between the pre-hung doorframe and the wall doorframe, which makes for a stronger end product.

Few people think about entire doorframes being crunched loose from their moorings, but I do. If anything–a stray tornado, a rabid grizzly bear, a wannabe home invader, or an out of bounds SWAT team–hits a door I’ve hung, I want the door to be able to hit back.

The door is hung, my way.

The door is hung, my way.

Another eccentricity is the way I add wall sheathing boards. The standard method is to stand them up, four feet wide by eight feet tall. On a larger structure, I will do that, too–but for these smaller additions (and especially for a perfect 8′ x 8′ square), I lay them sideways, with the greater length running horizontally. This way, each board covers the entire length of the structure with no joints to consider. The weight of the second board, pressing down on the bottom board, seals the seam between the two boards quite firmly.

Sheathing board (OSB strand board) manufacturers recommend installing the boards with 1/8″ gaps between them and/or roof clips for the roof, and I don’t do that, either. Always, I jam them as tightly together as they will go. The pros will likely prophesy that my buildings will expand and contract themselves into oblivion, but we’ve been living in the Border Fort since May of 2010 and it hasn’t happened yet.

Why do I do it the way I do? Simple: My gut says spacing the boards makes everything weaker, and that’s unacceptable.

As for laying wall sheathing sideways, think of it as a vertical roof. Standard roof technique does lay boards that way.

Beginning to sheathe the walls.

Beginning to sheathe the walls.

It looks like a box, you say?  Why yes, yes it does.

It looks like a box, you say? Why yes, yes it does.

The Border Fort walls are anything but straight up and down, a result of based on earthbag walls (covered with stucco).  The addition's wall sheathing boards had to be cut in artistic curves to fit.

The Border Fort walls are anything but straight up and down, a result of being based on earthbag walls (covered with stucco). The addition’s wall sheathing boards had to be cut in artistic curves to fit.

Looking good.

Looking good.

After a pause to install the door locks, it was on to the upper level–i.e., roof trusses.

A pause to install the door locks, and then...

A pause to install the door locks, and then…

...on to the roof trusses, secured with hurricane ties to the wall framing.

…on to the roof trusses, secured with hurricane ties to the wall framing.

The roof trusses were up when I really began to worry. Something unforeseen had slipped into the building equation.

In every other building and/or addition I’ve ever built, a strong roof truss ran right over the top of the doorframe(s) providing plenty of strength to keep the roof aloft and level over the years. But this one was different. I was bringing the door out under the eaves. One of the trusses extended right out over the middle of the doorway, adding stress to the framing header in that area rather than keeping weight level all the way across the opening.

I didn’t like that one little bit.

Before long, though, I came up with a plan. Rather than explain that plan in advance, let’s go through it a step at a time.

First, it would be necessary to pour the concrete for the porch’s front step. I hadn’t originally planned to do that until next spring, but now it was essential…and this time, I remembered to super-soup the Maximizer.

The step came out a work of art.

This time, I remembered to super-soup the Maximizer.

This time, I remembered to super-soup the Maximizer.

Once the concrete step had cured enough to stand on without disturbing it (but still some days before the forms would be removed), my masterpiece was added: Two vertical two by fours supporting a tiny, four foot truss. Additional studs were installed inside the wall to match up with those exterior verticals, and the combination was nailed firmly together. The truss was nailed wherever framing lumber was present (behind the sheathing) to receive the nails, but especially along the central vertical piece. Since there was extra thickness (the sheathing board between the two pieces of lumber), 16d nails were used instead of the usual 10d size.

Why is this a masterpiece? Two reasons:

    1. There is now a supportive truss directly supporting the doorway-center down-pushing roof truss. The roof will not sag.

    2. Despite being first and foremost functional in nature, the new truss and its verticals look extremely decorative, as if done purely for the aesthetics of the thing.

The truss facing the camera now supports the down-pushing roof truss directly above it.

The truss facing the camera now supports the down-pushing roof truss directly above it.

When I told the manager at Southwest Truss my plan, he understood, laughed…and had the truss built for me for free. I really appreciated the gesture. Sure, I keep going back to Jim and his crew for every new roofing project I undertake, but he didn’t have to do that.

With the “safety truss” in place, I could go ahead with the roofing, which I’d not wanted to add until that area over the door was strengthened to my taste. As always, the roofing involved three layers: Sheathing (OSB strand boards) secured with 8d nails, 30# roofing felt pinned down with staples, and steel roofing panels screwed down tight with watertight roofing screws.

Roof sheathing boards being applied.

Roof sheathing boards being applied.

Roofing felt in place.

Roofing felt in place.

Steel roofing panels, getting there.

Steel roofing panels, getting there.

With the roofing done, there remained only the “piddly but important” tasks of finishing the sheathing process at the west end (covering the end truss) and under the eaves between the trusses. For the end covering, a single 8′ piece of OSB strand board was cut to fit the remaining opening and simply nailed in place.

For the fill-in spots between rafters, however, the process is a little trickier. First, a piece of 2″ x 4″ (or, in the case of the front wall, a piece of 2″ x 6″) is cut to fit each slot between the trusses above the stud wall header boards. It’s then nailed into place and serves as a base “wall” to which strand board pieces can be nailed after they are cut to fit vertically between the trusses on the exterior wall.

6d nails are used for this part of the project; anything larger makes it hard to keep the small pieces of wood in place without splitting or shifting out of position during the process.

There were a couple of holes left after the top wall board was installed, so a bit of silicone sealant was applied to keep out the weather for now.

There were a couple of holes left after the top wall board was installed, so a bit of silicone sealant was applied to keep out the weather for now.

Inside the porch/shed, short pieces of 2" x 4" (or 2" x 6") are nailed atop the header boards to fill the spaces between trusses.

Inside the porch/shed, short pieces of 2″ x 4″ (or 2″ x 6″) are nailed atop the header boards to fill the spaces between trusses.

On the outside, small cut-to-fit pieces of OSB strand board fill in the final gaps.

On the outside, small cut-to-fit pieces of OSB strand board fill in the final gaps.

This again marks a building eccentricity of mine. Rather than cover the ends of the rafters with fascia boards and such, I prefer to leave them exposed. My reasoning is simple: I detest fascia boards. I don’t like working with them in any way, shape, or form, and I’ve seen fascia board installations go very, very sour. They can trap moisture and rot with surprising quickness or, alternatively, wind up serving as nesting hidey holes for all sorts of critters the sane homeowner would prefer not to have nesting there.

Anyway, with the final little pieces in place, the new back porch aka hot water tank enclosure aka tool shed is now complete. Stucco will be added when the weather warms up, and paint both before and after, but that can wait until our household of three is luxuriating in endless city style hot water, off grid or no off grid.

Ah. One last image. I mentioned that the concrete step turned out to be “a work of art” but provided no photo of said step after the concrete forms were removed. The reason: Couldn’t find any in my files. Probably skipped over them.

To make amends, I just went out and took a picture of the step by photo flash.

The "work of art" concrete step.  Admittedly, it could use a hosing off....

The “work of art” concrete step. Admittedly, it could use a hosing off….

Oops. Here’s the picture I was looking for–had it all along, the final product, including the step.

The final product, lacking only stucco (which has to wait for warmer weather) and paint.

The final product, lacking only stucco (which has to wait for warmer weather) and paint.

4 thoughts on “How To Build a Back Porch aka Hot Water Tank Enclosure aka Tool Shed

  1. Looks good. I hope you kept the camera inside or in a ziplock bag while doing the concrete work. We would hate for you to have to get another camera.

  2. Thanks, Sha. The enclosure now has the hot water tank up and running, plus one of 3 corner stacks of shelves (7 shelves high) to help organize the tool storage. Two corners to go…and then maybe a few corners in the FRONT porch as well….

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