Wednesday, August 20, 2008

Constructing septic tank access covers

When our septic tank was installed, it was simply covered with sand, gravel, and dirt. This is no good when/if you need to get the tank pumped out as you have to find the access covers. This would be even worse if you had to find the covers when the ground was frozen or there was a lot of snow cover. We planned to finish this area with some flagstone that we have stashed away, but before we put that down we had a little project to find the access covers and create an easier access for them.

This photo story is from August 20th. David Reddekkopp came over and gave me a hand with the project. (David actually did most of the work as I had a raging migraine.) It took quite a while to find the first access cover. We initially used my memory to locate the first hole we dug, but after digging halfway through to Taiwan it was obvious that my memory was was worthless. :( So I went back to my photo library and found two photos that helped us locate the access covers.

This photo was taken after about 2 1/2 hours of work. David is standing on the first access cover.

The access covers are 30" (2 1/2 feet) across -- bigger than I had remembered. I thought the covers were about 2' across, which is what I used to calculate how much wood I needed. The covers were also deeper than I had expected - about 20" vs expected 12"... This meant I didn't have enough wood....

Digging is hard work, and David is relaxing a bit, taking a break.

Tawny was curious about the hole. I suspect that maybe she could smell a bit of the fumes from the septic tank, but she was a bit timid about jumping into the hole.

However, jump into the hole she did... Taz is curious but he's a bit more timid than Tawny is.

This is the box that we built to put over the access cover. This box is 3' square and has pressure treated fence boards on the exterior where the wood is in contact with the soil.

Because the big rock is slightly sticking out above the access cover, we had to make some adjustments to the box because of it.

David wasn't that comfortable using a circular saw but he got some practice in. Here David is cutting the angle on a piece of fence board for the side.

This is what the box looks like with the first piece of wood on the top. After this photo was taken, I pulled some landscape fabric through on the side with the customize boards to help keep the sand/gravel from washing in through any openings.

Here David is looking pretty pleased. Why, you ask? Well, it's because of this...

The first access cover is completed, including a custom notch for rock. Because of the gap around the box, Tawny was quite afraid to jump across to the top. Once I filled in the gap with sand and gravel so there wasn't any yawning chasm between the gravel and the box, neither Tawny nor Taz had any fears when stepping onto the top of the cover.

Freda and I had looked for some kind of manufactured stones to put on the cover, as the stone we have is irregular. In the end, we settled on 18" square rubber tiles (made from reycled tire crumb rubber). Although it is slightly more expensive, we think this would be better as it is not as heavy as concrete pavers, and also because the rubber is flexible, we don't have any worries about cracking.

If you're comparing prices, Home Depot charged ~$10 for a 12" round rubber circle, and Rona charged ~$7.75 for an 18" square rubber tile. On a per square foot basis, HD was over $10/sf and Rona was about $3.50/sf (18" square tile is 2 1/4 s.f.), or about 1/3 the price of HD...

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