Building a Custom Portable Generator Shed

I went ahead and bought a second portable generator (CAT 7500) so I am stuck having 2 portable generators sitting in my garage (instead of my car). With winter approaching, I definitely want my car back in the garage so I need to come up with a storage solution.

One of the most popular way of storing portable generators was to re-purpose a plastic tool storage shed. Because it was relatively inexpensive and quick to assemble (and it looked like a standby generator when done), I saw tons of people going wit this method (you can read my Lifetime Horizontal Shed review here).

Another large segment of people constructed their own wood mini sheds but nothing really captured all the featured I wanted so I decided to just build my own.

Table of Contents

• Feature Wish list
• Building base
• Framing the Platform
• Framing the Walls / Roof
• Siding (coming soon)
• Roofing (coming soon)
• Heat Control (coming soon)
• Sound Control (coming soon)
• Refueling Safety (coming soon)

Portable Generator Shed Features – Wish list

I probably can’t satisfy them all but here is my wish list:

• Fire safety;
• Located on a high, dry ground to minimize water/moisture damage;
• Low center of gravity (to reduce the risk of tipping over during high-wind situations);
• Effective heat control;
• Minimize sound while running the generator;
• In-place service accessibility;
• Minimize water contamination during re-fueling;

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Building Base Choices

There are many options but it basically breaks down into 4 choices:

• Option # 1 – Place the generator shed on dirt or grass (direct contact). This is the easiest method where a shed sits on a pair of PT 4x4s. I prefer a location with plenty of ventilation and drainage, neither of which are provided by packed soil. Plus, packed soil can pool water during heavy down pour and I definitely dobn’t want to stand in it while working on a generator;
• Option # 3 – Place the generator shed on gravel;Situating a structure on gravel prevents direct contact with water due to drainage as well as allow ventilation underside, potentially reducing the risk of rot.
• Option # 4 – Place the generator shed on a concrete pad;This is the best option if your budget can support it and you know you will be living in your house long-term.

Although I liked the concrete pad idea, I wasn’t sure I would keep my generator in this particular location long term. So the thought of possibly moving a 1,500 lbs concrete pad (that’s how much it would weigh when creating a 6 ft length x 4 ft width x 8 in deep base) or .41 cubic yards of concrete (Sakrete has a nifty calculator – http://www.sakrete.com/product-calculators ), didn’t sound too appetizing.

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GROUND PREP

What I decided was to create a landing pad consisting of packed sand and 3/4″ driveway gravel to ensure level ground that will drain away water. I created a similar setup with my first shed (link here to read my article) with good success.

• STEP # 1 – The original location was on the corner of the deck so I decided to re-purpose the old sandbox play area which was directly adjacent to it;
• STEP # 2 – Remove sand (top layer) from the sandbox;
• STEP # 3 – Remove gravel (bottom layer) from the sandbox;
• STEP # 4 – Remove redwood sandbox frame;
• STEP # 5 – Clear debris;
• STEP # 6 – Mark 8 ft x 7 ft area with wood stakes / re-bar stakes;
• STEP # 7 – Remove rocks and do a rough clearing to level the ground;
• STEP # 8 – Lay down landscaping fabric (to prevent weeds from growing underneath);
• STEP # 9 – Lay down sand; tamper down; check level using 6 ft level;

• STEP # 10 – Lay down a second layer of landscaping fabric;
• STEP # 11 – Place 2 concrete footing blocks on each corner;

• STEP # 12 – Place 4 concrete footing blocks (2 stacked per corner) on each corner; 2 stacked concrete blocks are required due to elevation; use construction adhesive to bond two concrete blocks together;
• STEP # 13 – Lay down approximately 6 inches of gravel and tamper down;

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FRAMING THE FLOOR PLATFORM

One slight change from yesterday’s work is that I added two more concrete blocks in the middle of the frame to give it bit more stability. And using my awesome Dodge Grand Caravan, I lugged some 2x6x8 PR lumber.

With the gravel landing pad completed, I moved on to constructing the foundation.

• STEP # 1 – Position two, 2x6x8s and two, 2x6x4s on a rectangular shape and screw them in;
• STEP # 2 – Attach one center beam in the middle of the rectangle than measure to verify that the rectangle is square;
• STEP # 3 – Attach additional floor joists, 16″ O.C.;
• STEP # 4 – Install joist blocking between floor joists;
• STEP # 5 – Screw down 3/4″ 4×8 PT plywood;

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FRAMING WALLS

With base padding complete, time to head over to Home Depot for lumber to install walls and roof rafters (and picked up some T11 sidings as well);

• STEP # 1 – Much like base framing, I follow the same pattern except this time, I use 2 x 4s to create the back wall;
• STEP # 2 – Side walls will not be supporting any weight so the space between two studs were made them wider to anticipate installing an intake fan at the end;

• STEP # 3 – I installed 2 x 4 on its side, then a 2 x6 header to support the rafters;
• STEP # 4 – Because the footprint was fairly small, I decided to go with 2 x 4 rafters with bird-mouth cuts

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FINAL WORDS

I will be posting updates as I progress through the generator shed project.

If you found this article to be useful, can you do me a favor and sign up for my newsletter so that I can send you updates on my DIY projects?

Lastly, if you have any questions, please leave a comment below.

Thanks and good luck with your DIY project!

REFERENCES

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