The Cedar Rain Bench

Ever since I moved into my new house I’ve been weighing the pros and cons of various different rainwater storage options (see also previous post).  There is the DIY 55-gallon drum setup that can include multiple drums connected together. Or the 500-1,500 gallon metal cistern option that would cost a minimum of $1,500 and be installed without any DIY required.  I have a very small yard that includes a narrow side yard on which I wanted to put the rainwater storage, so size/dimensions were also factors in my decision.  I ended up purchasing liners, a diverter to connect to the gutter downspout, and plans to build two cisterns/benches – one for a 300 gallon bench and the other for a 65 gallon bench. The products are called “300 gallon cedar rain bench DIY – 3 liners only kit” plus the “DIY diverter/combo kit” at http://www.secondrain.com/. The total cost was $258.78.  In total, I had four (4) 140-gallon liners, although the bench designs do not accommodate the full capacity of the liners. There were no reviews posted of this at the time but there were a few youtube videos about this product.  I took my chances!
With the two packages I purchased, I hoped to achieve ~500 gallons of storage in 1 long cedar rain bench and 1 small bench, assuming I would slightly modify the designs to take more advantage of the size of the liners. After reading through the plans for the long (300 gallon) bench, I quickly realized these are not easily modified. There is such little instruction provided I would basically have to start from scratch.  I wasn’t up for that so I decided to follow the plans as written.  Luckily my good friend Brian came over to help me out!  See http://www.secondrain.com/cedar-rain-bench-tiny-house-nation/ for images of the 300 gallon bench.
I took the materials list to my local box stores to purchase the cedar.  Of course, they did not have all the items I needed, but I was able to get the 2x4s, 1x2s, screws, and hinges.  Then I drove 45 miles to a lumber store that actually sells cedar tongue and groove (t&g).  This was extraordinarily expensive and only came in 10′ lengths (not 8′ as the plans specify).  I live in a major city but this was the only place that sells this type of material.  My total spending on lumber alone was just over $400.  WOW.  Not such a cost-effective option after all.
Brian and I cut down the pieces and then painted them with boiled linseed oil.  This helps to protect the cedar from the effects of weather and is very safe for the environment.  It is time consuming but worthwhile to extend the life of your wood.
I’m not a master carpenter by any stretch of the imagination, but I do some woodworking and have a nice inventory of tools available.  I was excited that this project had already been designed and all I needed to do was follow the set of plans.  I figured I’d be done before lunch!  I followed the instructions closely.  The first thing I noticed was how sparse the instructions for the bench are. Very important details were not mentioned at all, and others were vague.  For example, the bench is made from cedar tongue and groove and the instructions do not specify if you need to cut off the tongue from the top/bottom pieces (except for one particular piece).  This seems to be quite important as the tongue is absolutely essential on some pieces and must be removed on others. Also, working with rough-cut cedar, the dimensions are going to vary a bit.  My cedar was about 1/8-1/4 inch thicker than what the instructions describe, so nothing fit together during the assembly stage.  I had to take many pieces apart and cut them down and reassemble.
Here are a few photos of the construction/assembly process:
And here is the finished bench.  It is really too tall to sit on as a bench, but I’m thinking of adding some stepping stones in front of it to add height and make sitting more comfortable.
Next step: hooking up the plumbing components.
The DIY diverter/combo kit was supposed to come with all the plumbing fittings needed for the small bench, which I thought I could source locally for the 300 gallon bench.  However, I found this to be far from accurate.  Firstly, the plumbing fittings needed are highly specialized and not widely available.  I had to order almost everything I needed online.  I’m not a plumber so I had to spend a lot of time trying to figure out what parts were needed and what they are called. Secondly, the parts provided were far from sufficient for a single bench.  Specifically, the diverter comes with a hose connection, so you need to buy a hose to connect that to the bench. Also, the fittings to connect the hose to the bench were not provided, and I had to buy 3 adapters/fittings to connect a standard garden hose to the 1” ID tubing, which cost $28 total.  The 1” ID tubing is also not common and the two tiny pieces provided with the kit are completely inadequate to do anything with them. A 10′ roll of 1” ID tubing cost me $18, and 2 packs were needed for the 300 gallon bench.  In sum, all of the plumbing parts I needed to buy for the 300 gallon bench ran ~$90.
I still haven’t finished adding the overflow tubing but here is a picture with the liners in place:
The first test of this bench happened to be during Houston’s near 500-year flood event on Memorial Day 2015.  It started raining after dark and I went out to check on things. There was a large flow of water exceeding the capacity of the diverter and overflowing onto the ground.  Duh… a standard garden hose is not exactly capable of handling all of the flow from a gutter. This is another thing I hadn’t considered – that I would not be able to capture all of the flow during a heavy rain event.  I intend to connect another hose to the second location on the diverter, but this is another expense and will still not accommodate all the water during heavy rain events.
The next morning this is what I found:
The pressure of the 300 gallons burst apart the t&g wall of the bench. Back to the drawing board.  The 2” screws they have you use are simply not long enough.  Perhaps this was exacerbated by the fact that my rough cut 2x4s were slightly bigger than those per the design, so a smaller amount of the screw extended into the t&g.  I had to drain all the water I worked so hard to capture in order to repair the bench.  I cut down the t&g to allow for some expansion/contraction between boards and then screwed everything together from the front with 2 1/4” screws.  It was also necessary to adjust the liners.  Although the instructions tell you to do this, there isn’t a lot you can do when the liners are empty and since they filled up overnight, I wasn’t able to adjust them when they were partially filled.
All in all, I have now spent over $850 on the liners, diverter, and supplies for 300 gallons of water storage.  This is quite a bit more than what I had budgeted and also a lot more than the $1-$2/gallon that rainwater storage should cost.  I still need to buy the materials and build a second bench to accommodate the last liner.
This project was a lot of work and not so simple as assembling Ikea furniture.  Hopefully SecondRain provides more detailed instructions and recommendations for sourcing the fittings in the future.
8/8/15 Update:
I have now completed the second bench. The design plan for this one was far more simple and also easy to modify (I made it larger) than the 300 gallon bench. The design provided by SecondRain was for 65 gallons of water storage. Since the liner accommodates up to 140 gallons, I went ahead and built the bench a bit bigger.
In contrast to the 300 gallon bench, there are no hinges on this bench but the lid can be lifted on/off.  It is a very simple design using treated plywood and 2×2 framing.  Since I had leftover t&g from the 300 gallon bench, I simply screwed it over the plywood on the exposed sides to make it look nicer.  As you can see the t&g is oriented in different directions on the two sides shown below; this was simply the best way for me to utilize the leftover material.
I attached a second garden hose to the downspout diverter to capture flow into this bench. The overflow from this one can then be directed into the garden or into the 300 gallon bench.
Summary:
My total cost for both benches is just over $1,000.  Based on my limited use of them so far, I have found some difficulty using all the water because when it gets down to a depth of about 1 foot, it won’t flow out of the hose.  I understand some people might pump the water out. Also, because the screen on the diverter is not great, a lot of dirt has accumulated in the liners and there is some algae growth since the benches do not block 100% of the light.  Overall, I would not recommend this system for rainwater storage.
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