The Generator House

Over the past few years, there have been several storms that have caused power outages that have lasted more than a few days, so many homes in the area have invested in generators to use as backup power. My client purchased a generator this summer and wanted it to be set-up outside, ready to be turned on at any time. The generator they purchased is a dual-power source generator, that can use a natural gas line from the house, or gas poured in from the top of the generator using a jerry can. It would need to be secured from theft, and also sheltered from the elements. I was asked to come up with a solution.

One thought was a yard bin that is often used for patio accessories or garbage cans. 

The issue with that is it can become inaccessible in the winter with snow and ice built-up. It also doesn't provide sufficient airflow for the generator. The recommended solution was a freestanding structure that would provide several benefits:

• sufficient fresh air intake
• clear path for the exhaust
• access to the natural gas line
• top access for filling with jerry can
• access to the power line that feeds the house
• easy access to the front instrument panel
• ability to use generator without snow/ice obstructions
• secured from theft

After taking measurements of the generator, a plan was designed on paper and transferred to Sketchup. It would meet all the requirements above, and also not look odd at the side the house. The structure would bring the generator up 4ft off the ground so that it would be convenient to access. The design would have a hinged roof so that the top can be opened to use a jerry can. To ensure the structure would have fresh air flow year round, there would be a mesh window at the back.

These were the Sketchup designs that were sent to the client for the project proposal. It was also used to generate the price quote, because the supplies could all be estimated from this model.

A big challenge was figuring out the appropriate footing for the structure. The wood was very heavy and the generator with fuel added even more weight. Due to the height of the structure, the footing would need to be secure, to ensure it wouldn't topple over. I consulted with folks at the hardware store, and several options were proposed, including cement deck blocks. 

These would allow the corner posts of the structure to stay above ground, but it would not secure the structure to the ground. If there were any pressure tipping the structure, the blocks wouldn't help. The best solution was determined to be digging deep post holes and driving the corners of the structure down into the ground. When the holes were filed, the structure would be completely immobilized. After some research, it was determined that 4ft depth was required to keep the posts from being moved by frost heave (when the ground freezes, it can push shallow posts upward each season, regardless of the their weight, so posts need to be deep enough to not be affected). 

A large amount of wood would be needed for this, and all of it would need to be sturdy - not only because of the weight of the generator and the structure itself, but it would also need to survive the elements (rain, ice, snow etc). The corner posts were 4x4 cedar, with cross beams made of 2x4 cedar. The panels were 3/4" plywood. With the corner posts being driven deep into the ground, the posts would need to be really long, so 10' posts were bought for the corners.

The first step was to build the sides, which would be connected with 2x4 cross beams. The tops of the posts were cut on the mitre saw at an angle, so the roof could be sloped. I would later learn that this wasn't the right angle so I would need to correct this after other assembly was done. The cross beams were cut to size and I connected them to the posts with pocket holes and exterior wood glue.

Once both sides were done, they were connected the same way - pocket holes and glue.

Throughout the build, the structure looked oddly tall and top-heavy, which it was. The posts would be buried in the ground once installed, so it would be much more reasonable then - but until that time, it looked odd in my driveway. It was also too tall to fit in my garage so all assembly was done outside. A tarp was used to cover it during rainy weather until it was protected with a roof and paint.

With the frame built, the floor and doors needed to be cut. I waited until the frame was assembled before measuring and cutting, to ensure that it would be the correct size. Corner notches were removed from the floor to fit around the corner posts.

Green tape was added to the ground level, to help visualize the exposed part of the posts.

The doors were cut and the sides of the panels were rounded with a router. To install the doors, I employed my son who would hold the doors in place while I screwed the hinges onto the posts.

the view from the back.

It was at this point that I realized that I had made a drastic error. The entire structure was too large. I checked my measurements of the generator again and noticed that when I made my Sketchup drawings, I had allotted too much extra space around the generator, which made the structure too big. This unit would be installed along the side of the clients' house, between their home and another property. There was a limited amount of space available to use and if my structure was too large, it would impede the access between the units. I needed to make the structure smaller in length and width....after already assembling it.

First step was to remove the doors and the floor board. Then I needed to mark almost the boards to be cut - removing almost 1 foot from the length and 8inches from the width. I removed the screws from the pocket holes, chopped a bunch off the board, re-drilled the pocket holes and re-assembled the structure. The doors were then re-cut and mounted back onto the frame. 

With the doors installed, it was time to cut the back boards. The back was going to be 2 parts. The bottom would be a solid piece, but the top section would have a hole cut into it. That hole would be filled with screen that would allow airflow to keep the generator from getting too humid in wet weather during storage.

The side doors of the structure would be held closed with barrel bolts from the inside. This would ensure that with only a pad-lock on the front doors, the whole structure would be secure. I added a piece of plywood to allow the bolt to reach further into floor board. 

The roof needed to built next. It would be heavy, but it needed the strength to hold any snow and ice that might build up on top. The frame of the roof would be made of 2x4 with half-lap joints. The boards were run over the table saw with dado blades to chew out the slots for the half-lap. 

cutting the rabbet into the end of the board for the half-lap

The channel in the middle of the board where the two boards will overlap

Dry fitting the boards before glue and screws were used.

The roof panel was added also. Note that the front of the roof has a tapered board - which gives clearance for the doors to open.

The roof is broad and hangs out over the front so that rain and snow won't fall into the structure when the doors are open. The hinges for the roof were attached to the corner posts in the back, which allows the top to tip open so that gas can be poured from the top. While filling the generator, the roof needs to stay open on it's own, so the client can pour the gas. I needed a way to prop the roof up, so a bar was cut with angles that would catch on the frame of the structure and the roof, and hold the roof up.

With all the assembly complete, it was time to start painting. First coat was primer, then acrylic exterior white paint - all applied with a paint sprayer for the first 2 coats. There are some areas that the sprayer wasn't ideal for, so I used a brush and roller to touch a few spots also.

Notice the mesh has been installed in the hole at the back of the structure.

The bottom of the corners posts weren't painted for a very particular reason. The posts would be buried in the holes in the ground, and those holes would be filled with an expanding foam product that would grab the posts and hold them secure. I wanted the foam to grab the wood and not the paint. Also, the cedar posts would be resistant to any rot regardless.

The roof would need more than just paint for it to be really weather resistant. I didn't want to use roofing shingles, because they are heavy and lifting the roof would be difficult. I decided corrugated aluminum would be best route to go. I consulted the experts at the hardware store, they referred me to a manufacturer who sent me down the road to a retailer. I gave them the specs and they ordered the metal roofing with some trim that would go around the 3/4" roof board. 

Special roofing screws were used that had built-in washers to press against the metal sheets. Unfortunately, the screws were longer than 3/4" so they protruded through the board. I needed to use my Dremel with the cutting wheel to cut the screws flush with the roof, so they wouldn't stick out and cut someone.

Here you can see the Dremel is about to cut the screw

This screw is almost cut through

The roof was left off the structure at this point (I obviously had to remove it to install the roofing metal). It would be too heavy to transport the structure with the roof installed anyways. The next thing I wanted to add were some sort of attachment that would keep the side doors open when the client wanted to run the generator. Ideally, when the generator was running, the side doors would be left open, to allow airflow in and out of the generator - but also to run the hoses out the left and right side of the generator for natural gas and the electrical power. I didn't want the doors to be flapping in the wind, so something needed to hold them open. I found something at the hardware store called a friction support arm, which is often used to keep chest lids open. I installed them on the side doors, and their friction or tightness can be adjusted by the client by tightening the screw. It prevents the doors from flapping entirely (so far!).

That was the last step in the build. Next was the installation at the home. This was complicated.

The structure was too large to fit into my van, and I didn't know anybody with a pickup truck that I could borrow. The client had actually rented a moving truck for their own work, so we used it to move the structure, with the help of his son and a friend. It was transported to his driveway safely.

To dig the holes for the posts, I needed to ensure that the ground was safe, so I ordered an inspection by the city (Call before you dig!). They checked to see if any utilities would be in the way. There was a gas line in the area where I would be digging, but the inspectors marked the location clearly, so I would be able to dig safely. I also needed to know where to dig the holes. I build a template of the footprint for the structure, and placed it at the installation site. The inside corners of the template were the locations where the posts would site.

My wife is an avid gardener, and loves planting tulips. To help her bury the tulips, I bought an auger bit for my drill. It can drill a hole for a tulip in seconds. It can also help drill a deep hole for my posts in just a couple minutes. Even buried rocks get removed with this handy accessory!

Once the holes were drilled, I needed to get the structure moved carefully over the holes and placed down straight, or else dirt would have filled the holes and the depth would have been different for each hole - and the whole structure wouldn't be sitting level. I asked the client's son and his friend to help move the structure - but between the 3 of us, it was still too heavy to move safely. It was very top heavy and wanted to tip over each time we were going to move it. The client wasn't home but he had a few buddies in the neighbourhood who came over and helped us get it done. It was stressful getting it in place safely.

Once the structure was down in the holes, I needed to work on filling the holes with the foam. The product is called Sika Post-Fix and it is a really nice product to use. A great alternative to cement (which is much messier to work with and takes longer to set).

Once the hole is ready to be filled, mix the product in the bag, snip the corner of the bag open and pour the product into the hole. It begins expanding instantly and fills the hole and grabs the post tightly. Once cured, the foam that rose above the hole can be trimmed with a blade. Weather resistant and permanent.

the green liquid foam was just poured and is about to start expanding

The foam was fully cured and expanded

The excess foam was cut with a saw and knife 

After the foam was cured and trimmed, the ground sheet was replaced and the river stone was shoveled back on top and around the posts. The job was done. Later, the client installed the generator into the structure and added a lock to the front latch. Now, all we need is for a power outage to truly test the setup!